Use XAML serialization instead of DataContractSerializer.

XAML serialization works better:
- it calls the object constructor, thus using the correct default value for new properties
- it can add to existing collections (created by constructor) and does not require a setter for collection properties
- it does not serialize options that were not changed from the [DefaultValue]

src/Main/Core/Project/ICSharpCode.Core.csproj

@@ -57,8 +57,8 @@
     <Reference Include="System.Core">
       <RequiredTargetFramework>3.5</RequiredTargetFramework>
     </Reference>
-    <Reference Include="System.Runtime.Serialization">
-      <RequiredTargetFramework>3.0</RequiredTargetFramework>
+    <Reference Include="System.Xaml">
+      <RequiredTargetFramework>4.0</RequiredTargetFramework>
     </Reference>
     <Reference Include="System.Xml" />
     <Reference Include="System.Xml.Linq">

src/Main/Core/Project/Src/Services/PropertyService/Properties.cs

@@ -6,15 +6,12 @@ using System.Collections;
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Diagnostics;
-using System.Globalization;
-using System.IO;
 using System.Linq;
 using System.Runtime.Serialization;
-using System.Text;
 using System.Threading;
+using System.Xaml;
 using System.Xml;
 using System.Xml.Linq;
-using System.Xml.Serialization;
 
 namespace ICSharpCode.Core
 {
@@ -232,7 +229,7 @@ namespace ICSharpCode.Core
 								array[i] = (T)Deserialize(serializedArray[i], typeof(T));
 							}
 							return array;
-						} catch (SerializationException ex) {
+						} catch (XamlObjectWriterException ex) {
 							LoggingService.Warn(ex);
 						}
 					} else {
@@ -317,9 +314,8 @@ namespace ICSharpCode.Core
 			if (key != null) {
 				element.Add(new XAttribute("key", key));
 			}
-			var s = new DataContractSerializer(sourceType);
 			using (var xmlWriter = element.CreateWriter()) {
-				s.WriteObject(xmlWriter, value);
+				XamlServices.Save(xmlWriter, value);
 			}
 			return element;
 		}
@@ -330,12 +326,11 @@ namespace ICSharpCode.Core
 				return null;
 			XElement element = serializedVal as XElement;
 			if (element != null) {
-				var s = new DataContractSerializer(targetType);
 				using (var xmlReader = element.CreateReader()) {
 					xmlReader.MoveToContent();
 					xmlReader.Read(); // skip <SerializedObject>
 					xmlReader.MoveToContent();
-					return s.ReadObject(xmlReader);
+					return XamlServices.Load(xmlReader);
 				}
 			} else {
 				string text = serializedVal as string;