diff --git a/dotnet/dist/AbortMultiPartsUpload.cs b/dotnet/dist/AbortMultiPartsUpload.cs
index b337c97..441463f 100644
--- a/dotnet/dist/AbortMultiPartsUpload.cs
+++ b/dotnet/dist/AbortMultiPartsUpload.cs
@@ -31,8 +31,8 @@ public class AbortMultiPartsUploadModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -112,4 +112,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/AppendObject.cs b/dotnet/dist/AppendObject.cs
new file mode 100644
index 0000000..68e89a2
--- /dev/null
+++ b/dotnet/dist/AppendObject.cs
@@ -0,0 +1,104 @@
+using COSXML.Common;
+using COSXML.CosException;
+using COSXML.Model;
+using COSXML.Model.Object;
+using COSXML.Model.Tag;
+using COSXML.Model.Bucket;
+using COSXML.Model.Service;
+using COSXML.Utils;
+using COSXML.Auth;
+using COSXML.Transfer;
+using System;
+using COSXML;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using System.Net;
+
+using System.Net.Security;
+using System.Security.Cryptography.X509Certificates;
+using COSXML.Log;
+using System.Net.Cache;
+using System.Collections;
+
+
+namespace COSSnippet
+{
+    public class AppendObjectModel {
+
+      private static CosXml cosXml;
+      private static int count = 0;
+
+      AppendObjectModel() {
+        CosXmlConfig config = new CosXmlConfig.Builder()
+          .SetRegion("") //设置一个默认的存储桶地域
+          .Build();
+        
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
+        long durationSecond = 600;          //每次请求签名有效时长，单位为秒
+        QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
+          secretKey, durationSecond);
+        
+        cosXml = new CosXmlServer(config, qCloudCredentialProvider);
+      }
+
+      /// 简单上传对象
+      public void AppendObject()
+      {
+        //.cssg-snippet-body-start:[Append-object]
+        try
+        {
+          string bucket = "examplebucket-1250000000"; //存储桶，格式：BucketName-APPID
+          string key = "exampleobject"; //对象键
+	        string srcPath = @"temp-source-file";//本地文件绝对路径
+       
+          //首次append上传,追加位置传0,创建一个appendable对象 
+          long next_append_position = 0;
+          AppendObjectRequest request = new AppendObjectRequest(bucket, key, srcPath, next_append_position);
+          //设置进度回调
+          request.SetCosProgressCallback(delegate (long completed, long total)
+          {
+            Console.WriteLine(String.Format("progress = {0:##.##}%", completed * 100.0 / total));
+          });
+          AppendObjectResult result = cosXml.AppendObject(request);
+          //获取下次追加位置
+          next_append_position = result.nextAppendPosition;
+          Console.WriteLine(result.GetResultInfo());
+          
+          //执行追加,传入上次获取的对象末尾
+          request = new AppendObjectRequest(bucket, key, srcPath, next_append_position);
+          request.SetCosProgressCallback(delegate (long completed, long total)
+          {
+            Console.WriteLine(String.Format("progress = {0:##.##}%", completed * 100.0 / total));
+          });
+          result = cosXml.AppendObject(request);
+          Console.WriteLine(result.GetResultInfo());
+        }
+        catch (COSXML.CosException.CosClientException clientEx)
+        {
+          //请求失败
+          Console.WriteLine("CosClientException: " + clientEx);
+        }
+        catch (COSXML.CosException.CosServerException serverEx)
+        {
+          //请求失败
+          Console.WriteLine("CosServerException: " + serverEx.GetInfo());
+        }
+        
+        //.cssg-snippet-body-end
+      }
+
+      // .cssg-methods-pragm
+
+      static void Main(string[] args)
+      {
+        AppendObjectModel m = new AppendObjectModel();
+        m.AppendObject();
+      }
+    }
+}
diff --git a/dotnet/dist/BucketACL.cs b/dotnet/dist/BucketACL.cs
index 6f126a2..0328cf2 100644
--- a/dotnet/dist/BucketACL.cs
+++ b/dotnet/dist/BucketACL.cs
@@ -29,8 +29,8 @@ public class BucketACLModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -111,4 +111,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/BucketCORS.cs b/dotnet/dist/BucketCORS.cs
index 6190805..3f00f1b 100644
--- a/dotnet/dist/BucketCORS.cs
+++ b/dotnet/dist/BucketCORS.cs
@@ -29,8 +29,8 @@ public class BucketCORSModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -186,4 +186,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/BucketDomain.cs b/dotnet/dist/BucketDomain.cs
index f59b10b..bc29eb9 100644
--- a/dotnet/dist/BucketDomain.cs
+++ b/dotnet/dist/BucketDomain.cs
@@ -29,8 +29,8 @@ public class BucketDomainModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -124,4 +124,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/BucketInventory.cs b/dotnet/dist/BucketInventory.cs
index 31a2163..818ed10 100644
--- a/dotnet/dist/BucketInventory.cs
+++ b/dotnet/dist/BucketInventory.cs
@@ -29,8 +29,8 @@ public class BucketInventoryModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -152,4 +152,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/BucketLifecycle.cs b/dotnet/dist/BucketLifecycle.cs
index b9a9cc0..c9b999b 100644
--- a/dotnet/dist/BucketLifecycle.cs
+++ b/dotnet/dist/BucketLifecycle.cs
@@ -29,8 +29,8 @@ public class BucketLifecycleModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -148,4 +148,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/BucketLogging.cs b/dotnet/dist/BucketLogging.cs
index e49539e..90f40a6 100644
--- a/dotnet/dist/BucketLogging.cs
+++ b/dotnet/dist/BucketLogging.cs
@@ -29,8 +29,8 @@ public class BucketLoggingModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -109,4 +109,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/BucketPolicy.cs b/dotnet/dist/BucketPolicy.cs
index d759c19..4b2dc54 100644
--- a/dotnet/dist/BucketPolicy.cs
+++ b/dotnet/dist/BucketPolicy.cs
@@ -29,8 +29,8 @@ public class BucketPolicyModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -77,4 +77,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/BucketReplication.cs b/dotnet/dist/BucketReplication.cs
index 24ad004..ea33efa 100644
--- a/dotnet/dist/BucketReplication.cs
+++ b/dotnet/dist/BucketReplication.cs
@@ -29,8 +29,8 @@ public class BucketReplicationModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -139,4 +139,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/BucketTagging.cs b/dotnet/dist/BucketTagging.cs
index 961f3e3..60673f4 100644
--- a/dotnet/dist/BucketTagging.cs
+++ b/dotnet/dist/BucketTagging.cs
@@ -29,8 +29,8 @@ public class BucketTaggingModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -143,4 +143,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/BucketVersioning.cs b/dotnet/dist/BucketVersioning.cs
index 6867207..7a75edd 100644
--- a/dotnet/dist/BucketVersioning.cs
+++ b/dotnet/dist/BucketVersioning.cs
@@ -29,8 +29,8 @@ public class BucketVersioningModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -101,4 +101,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/BucketWebsite.cs b/dotnet/dist/BucketWebsite.cs
index 85f2f1f..b0f5f9d 100644
--- a/dotnet/dist/BucketWebsite.cs
+++ b/dotnet/dist/BucketWebsite.cs
@@ -29,8 +29,8 @@ public class BucketWebsiteModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -136,4 +136,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/CopyObject.cs b/dotnet/dist/CopyObject.cs
index 151a6b9..eafe386 100644
--- a/dotnet/dist/CopyObject.cs
+++ b/dotnet/dist/CopyObject.cs
@@ -29,8 +29,8 @@ public class CopyObjectModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -132,4 +132,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/CustomCredentialProvider.cs b/dotnet/dist/CustomCredentialProvider.cs
index 11a844b..1075cfd 100644
--- a/dotnet/dist/CustomCredentialProvider.cs
+++ b/dotnet/dist/CustomCredentialProvider.cs
@@ -17,8 +17,8 @@ public CustomQCloudCredentialProvider(): base(null, null, 0L, null) {
       public override void Refresh()
       {
         //... 这里通过腾讯云请求临时密钥
-        string tmpSecretId = "COS_SECRETID"; //"临时密钥 SecretId";
-        string tmpSecretKey = "COS_SECRETKEY"; //"临时密钥 SecretKey";
+        string tmpSecretId = "SECRET_ID"; //"临时密钥 SecretId";
+        string tmpSecretKey = "SECRET_KEY"; //"临时密钥 SecretKey";
         string tmpToken = "COS_TOKEN"; //"临时密钥 token";
         long tmpStartTime = 1546861202;//临时密钥有效开始时间，精确到秒
         long tmpExpiredTime = 1546862502;//临时密钥有效截止时间，精确到秒
@@ -34,4 +34,4 @@ public void init() {
     }
   }
 
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/DeleteBucket.cs b/dotnet/dist/DeleteBucket.cs
index 01a3d6a..33715de 100644
--- a/dotnet/dist/DeleteBucket.cs
+++ b/dotnet/dist/DeleteBucket.cs
@@ -29,8 +29,8 @@ public class DeleteBucketModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -76,4 +76,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/DeleteObject.cs b/dotnet/dist/DeleteObject.cs
index 53d169e..e74cfa5 100644
--- a/dotnet/dist/DeleteObject.cs
+++ b/dotnet/dist/DeleteObject.cs
@@ -29,8 +29,8 @@ public class DeleteObjectModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -171,4 +171,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/GetAuthorization.cs b/dotnet/dist/GetAuthorization.cs
index 5931d36..1590fcf 100644
--- a/dotnet/dist/GetAuthorization.cs
+++ b/dotnet/dist/GetAuthorization.cs
@@ -29,8 +29,8 @@ public class GetAuthorizationModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -57,4 +57,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/GetObject.cs b/dotnet/dist/GetObject.cs
index be24ab8..ac689e1 100644
--- a/dotnet/dist/GetObject.cs
+++ b/dotnet/dist/GetObject.cs
@@ -29,8 +29,8 @@ public class GetObjectModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -116,4 +116,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/GetService.cs b/dotnet/dist/GetService.cs
index 50f601b..5e3ab35 100644
--- a/dotnet/dist/GetService.cs
+++ b/dotnet/dist/GetService.cs
@@ -29,8 +29,8 @@ public class GetServiceModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -114,4 +114,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/HeadBucket.cs b/dotnet/dist/HeadBucket.cs
index 0678d77..850e3e7 100644
--- a/dotnet/dist/HeadBucket.cs
+++ b/dotnet/dist/HeadBucket.cs
@@ -29,8 +29,8 @@ public class HeadBucketModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -76,4 +76,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/HeadObject.cs b/dotnet/dist/HeadObject.cs
index 279c31d..134164b 100644
--- a/dotnet/dist/HeadObject.cs
+++ b/dotnet/dist/HeadObject.cs
@@ -29,8 +29,8 @@ public class HeadObjectModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -77,4 +77,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/ListObjects.cs b/dotnet/dist/ListObjects.cs
index edfed65..c335d40 100644
--- a/dotnet/dist/ListObjects.cs
+++ b/dotnet/dist/ListObjects.cs
@@ -30,8 +30,8 @@ public class ListObjectsModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -146,4 +146,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/ListObjectsVersioning.cs b/dotnet/dist/ListObjectsVersioning.cs
index 0dc19e2..4a9f1a3 100644
--- a/dotnet/dist/ListObjectsVersioning.cs
+++ b/dotnet/dist/ListObjectsVersioning.cs
@@ -31,8 +31,8 @@ public class ListObjectsVersioningModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -124,4 +124,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/ModifyObjectProperty.cs b/dotnet/dist/ModifyObjectProperty.cs
index a1e2b43..0a46e77 100644
--- a/dotnet/dist/ModifyObjectProperty.cs
+++ b/dotnet/dist/ModifyObjectProperty.cs
@@ -29,8 +29,8 @@ public class ModifyObjectPropertyModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -130,4 +130,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/MoveObject.cs b/dotnet/dist/MoveObject.cs
index 4f2b105..1ee3dde 100644
--- a/dotnet/dist/MoveObject.cs
+++ b/dotnet/dist/MoveObject.cs
@@ -29,8 +29,8 @@ public class MoveObjectModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -88,4 +88,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/MultiPartsCopyObject.cs b/dotnet/dist/MultiPartsCopyObject.cs
index 90b8355..43e9a81 100644
--- a/dotnet/dist/MultiPartsCopyObject.cs
+++ b/dotnet/dist/MultiPartsCopyObject.cs
@@ -31,8 +31,8 @@ public class MultiPartsCopyObjectModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -161,4 +161,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/MultiPartsUploadObject.cs b/dotnet/dist/MultiPartsUploadObject.cs
index d031d94..e226dd9 100644
--- a/dotnet/dist/MultiPartsUploadObject.cs
+++ b/dotnet/dist/MultiPartsUploadObject.cs
@@ -31,8 +31,8 @@ public class MultiPartsUploadObjectModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -217,4 +217,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/ObjectACL.cs b/dotnet/dist/ObjectACL.cs
index a9261b9..e7e8371 100644
--- a/dotnet/dist/ObjectACL.cs
+++ b/dotnet/dist/ObjectACL.cs
@@ -29,8 +29,8 @@ public class ObjectACLModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -115,4 +115,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/ObjectPresignUrl.cs b/dotnet/dist/ObjectPresignUrl.cs
index 578b157..5c18fc2 100644
--- a/dotnet/dist/ObjectPresignUrl.cs
+++ b/dotnet/dist/ObjectPresignUrl.cs
@@ -29,8 +29,8 @@ public class ObjectPresignUrlModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -148,4 +148,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/ObjectTagging.cs b/dotnet/dist/ObjectTagging.cs
index 912c49e..307b0d5 100644
--- a/dotnet/dist/ObjectTagging.cs
+++ b/dotnet/dist/ObjectTagging.cs
@@ -29,8 +29,8 @@ public class ObjectTaggingModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -77,4 +77,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/PictureOperation.cs b/dotnet/dist/PictureOperation.cs
index fc266f4..73547f5 100644
--- a/dotnet/dist/PictureOperation.cs
+++ b/dotnet/dist/PictureOperation.cs
@@ -32,8 +32,8 @@ public class PictureOperationModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -188,4 +188,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/PostObject.cs b/dotnet/dist/PostObject.cs
index 2eae089..23e4a0c 100644
--- a/dotnet/dist/PostObject.cs
+++ b/dotnet/dist/PostObject.cs
@@ -29,8 +29,8 @@ public class PostObjectModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -83,4 +83,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/PutBucket.cs b/dotnet/dist/PutBucket.cs
index 03400df..edf45fb 100644
--- a/dotnet/dist/PutBucket.cs
+++ b/dotnet/dist/PutBucket.cs
@@ -29,8 +29,8 @@ public class PutBucketModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -110,4 +110,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/PutObject.cs b/dotnet/dist/PutObject.cs
index 4e7d0a2..446db72 100644
--- a/dotnet/dist/PutObject.cs
+++ b/dotnet/dist/PutObject.cs
@@ -29,8 +29,8 @@ public class PutObjectModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -84,4 +84,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/PutObjectCSE.cs b/dotnet/dist/PutObjectCSE.cs
index 1081aed..afe294d 100644
--- a/dotnet/dist/PutObjectCSE.cs
+++ b/dotnet/dist/PutObjectCSE.cs
@@ -29,8 +29,8 @@ public class PutObjectCSEModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -67,4 +67,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/PutObjectSSE.cs b/dotnet/dist/PutObjectSSE.cs
index ecf5afe..7e6a8ff 100644
--- a/dotnet/dist/PutObjectSSE.cs
+++ b/dotnet/dist/PutObjectSSE.cs
@@ -29,8 +29,8 @@ public class PutObjectSSEModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -92,4 +92,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/QrcodeRecognition.cs b/dotnet/dist/QrcodeRecognition.cs
index 13160af..5b493d8 100644
--- a/dotnet/dist/QrcodeRecognition.cs
+++ b/dotnet/dist/QrcodeRecognition.cs
@@ -32,8 +32,8 @@ public class QrcodeRecognitionModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -96,4 +96,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/RestoreObject.cs b/dotnet/dist/RestoreObject.cs
index fc075a0..1e3ded6 100644
--- a/dotnet/dist/RestoreObject.cs
+++ b/dotnet/dist/RestoreObject.cs
@@ -29,8 +29,8 @@ public class RestoreObjectModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -81,4 +81,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/SelectObject.cs b/dotnet/dist/SelectObject.cs
index d0c0eba..d84ee0d 100644
--- a/dotnet/dist/SelectObject.cs
+++ b/dotnet/dist/SelectObject.cs
@@ -29,8 +29,8 @@ public class SelectObjectModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -90,4 +90,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/SetCustomDomain.cs b/dotnet/dist/SetCustomDomain.cs
index 193076a..45bee52 100644
--- a/dotnet/dist/SetCustomDomain.cs
+++ b/dotnet/dist/SetCustomDomain.cs
@@ -29,8 +29,8 @@ public class SetCustomDomainModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -106,4 +106,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/SetCustomHeaders.cs b/dotnet/dist/SetCustomHeaders.cs
index b1c3705..35eabcb 100644
--- a/dotnet/dist/SetCustomHeaders.cs
+++ b/dotnet/dist/SetCustomHeaders.cs
@@ -29,8 +29,8 @@ public class SetCustomHeadersModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -66,4 +66,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/TransferCopyObject.cs b/dotnet/dist/TransferCopyObject.cs
index 14d7f0d..feed7e6 100644
--- a/dotnet/dist/TransferCopyObject.cs
+++ b/dotnet/dist/TransferCopyObject.cs
@@ -29,8 +29,8 @@ public class TransferCopyObjectModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -83,4 +83,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/TransferDownloadObject.cs b/dotnet/dist/TransferDownloadObject.cs
index b82aef9..0601332 100644
--- a/dotnet/dist/TransferDownloadObject.cs
+++ b/dotnet/dist/TransferDownloadObject.cs
@@ -29,8 +29,8 @@ public class TransferDownloadObjectModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -134,7 +134,7 @@ public async void DownloadObjectTrafficLimit()
       }
 
       /// 设置支持断点下载
-      public void TransferDownloadResumable()
+      public async void TransferDownloadResumable()
       {
         TransferConfig transferConfig = new TransferConfig();
         
@@ -150,8 +150,17 @@ public void TransferDownloadResumable()
                 cosPath, localDir, localFileName);
         //.cssg-snippet-body-start:[transfer-download-resumable]
         COSXMLDownloadTask downloadTask = new COSXMLDownloadTask(request);
+        //开启断点续传，当本地存在未下载完成文件时，追加下载到文件末尾
+        //本地文件已存在部分内容可能导致下载失败，请删除重试
         downloadTask.SetResumableDownload(true);
-        
+        try {
+          COSXML.Transfer.COSXMLDownloadTask.DownloadTaskResult result = await 
+            transferManager.DownloadAsync(downloadTask);
+          Console.WriteLine(result.GetResultInfo());
+          string eTag = result.eTag;
+        } catch (Exception e) {
+            Console.WriteLine("CosException: " + e);
+        }
         //.cssg-snippet-body-end
       }
 
@@ -178,4 +187,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}
diff --git a/dotnet/dist/TransferUploadObject.cs b/dotnet/dist/TransferUploadObject.cs
index 8594641..307dced 100644
--- a/dotnet/dist/TransferUploadObject.cs
+++ b/dotnet/dist/TransferUploadObject.cs
@@ -29,8 +29,8 @@ public class TransferUploadObjectModel {
           .SetRegion("COS_REGION") //设置一个默认的存储桶地域
           .Build();
         
-        string secretId = "COS_SECRETID";   //云 API 密钥 SecretId
-        string secretKey = "COS_SECRETKEY"; //云 API 密钥 SecretKey
+        string secretId = "SECRET_ID";   //云 API 密钥 SecretId
+        string secretKey = "SECRET_KEY"; //云 API 密钥 SecretKey
         long durationSecond = 600;          //每次请求签名有效时长，单位为秒
         QCloudCredentialProvider qCloudCredentialProvider = new DefaultQCloudCredentialProvider(secretId, 
           secretKey, durationSecond);
@@ -245,4 +245,4 @@ static void Main(string[] args)
         // .cssg-methods-pragma
       }
     }
-}
\ No newline at end of file
+}