Merge pull request #25 from thenderson21/master

Added validation property to SetProperty<T>()
jamesmontemagno · Feb 5, 2018 · 8d5622a · 8d5622a
2 parents ff4e24d + f0653cd
commit 8d5622a
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Showing 3 changed files with 68 additions and 11 deletions.
diff --git a/MvvmHelpers.Tests/ObservableObjectTests.cs b/MvvmHelpers.Tests/ObservableObjectTests.cs
@@ -46,7 +46,6 @@ public void OnDidntChange()
             person.FirstName = "James";
 
 
-
             Assert.IsNull(updated, "Property changed was raised, but shouldn't have been");
         }
 
@@ -64,6 +63,55 @@ public void OnChangedEvent()
 
             Assert.IsTrue(triggered, "OnChanged didn't raise");
         }
+
+		[Test()]
+		public void ValidateEvent()
+		{
+            var contol = "Motz";
+			var triggered = false;
+            person.Validate = (oldValue, newValue) =>
+			{
+                triggered = true;
+                return oldValue != newValue;
+			};
+
+			person.FirstName = contol;
+
+			Assert.IsTrue(triggered, "ValidateValue didn't raise");
+            Assert.AreEqual(person.FirstName, contol, "Value was not set correctly.");
+
+		}
+
+		[Test()]
+		public void NotValidateEvent()
+		{
+            var contol = person.FirstName;
+			var triggered = false;
+			person.Validate = (oldValue, newValue) =>
+			{
+				triggered = true;
+                return false;
+			};
+
+			person.FirstName = "Motz";
+
+			Assert.IsTrue(triggered, "ValidateValue didn't raise");
+			Assert.AreEqual(person.FirstName, contol, "Value should not have been set.");
+
+		}
+
+		[Test()]
+		public void ValidateEventException()
+		{
+			person.Validate = (oldValue, newValue) =>
+			{
+                throw new ArgumentOutOfRangeException();
+				return false;
+			};
+
+            Assert.Throws<ArgumentOutOfRangeException>(() => person.FirstName = "Motz", "Should throw ArgumentOutOfRangeException");
+
+		}
     }
 }
 
diff --git a/MvvmHelpers.Tests/Person.cs b/MvvmHelpers.Tests/Person.cs
@@ -9,16 +9,19 @@ public class PersonViewModel : BaseViewModel
 
     }
 
-    public class Person : ObservableObject
-    {
+   public class Person : ObservableObject
+   {
         public Action Changed { get; set; }
+
+        public Func<string, string, bool> Validate {get;set;}
+
         string firstName;
         public string FirstName
         {
             get { return firstName; }
             set
             {
-                SetProperty(ref firstName, value, onChanged: Changed);
+            SetProperty(ref firstName, value, onChanged: Changed, validateValue: Validate);
             }
         }
         string lastName;
@@ -27,9 +30,11 @@ public string LastName
             get { return lastName; }
             set
             {
-                SetProperty(ref lastName, value, onChanged: Changed);
+                SetProperty(ref lastName, value, onChanged: Changed, validateValue: Validate);
             }
         }
+
+
         public string SortName
         {
             get { return FirstName[0].ToString().ToUpperInvariant(); }

diff --git a/MvvmHelpers/ObservableObject.cs b/MvvmHelpers/ObservableObject.cs
@@ -16,15 +16,18 @@ public class ObservableObject : INotifyPropertyChanged
         /// <returns><c>true</c>, if property was set, <c>false</c> otherwise.</returns>
         /// <param name="backingStore">Backing store.</param>
         /// <param name="value">Value.</param>
+        /// <param name="validateValue">Validates value.</param>
         /// <param name="propertyName">Property name.</param>
         /// <param name="onChanged">On changed.</param>
         /// <typeparam name="T">The 1st type parameter.</typeparam>
         protected virtual bool SetProperty<T>(
             ref T backingStore, T value,
             [CallerMemberName]string propertyName = "",
-            Action onChanged = null)
+            Action onChanged = null,
+            Func<T, T, bool> validateValue = null)
         {
-            if (EqualityComparer<T>.Default.Equals(backingStore, value))
+         if ((validateValue == null && EqualityComparer<T>.Default.Equals(backingStore, value)) ||
+             (validateValue != null && !validateValue(backingStore, value)))
                 return false;
 
             backingStore = value;
@@ -33,10 +36,11 @@ protected virtual bool SetProperty<T>(
             return true;
         }
 
-        /// <summary>
-        /// Occurs when property changed.
-        /// </summary>
-        public event PropertyChangedEventHandler PropertyChanged;
+
+      /// <summary>
+      /// Occurs when property changed.
+      /// </summary>
+      public event PropertyChangedEventHandler PropertyChanged;
 
         /// <summary>
         /// Raises the property changed event.