Fixed SD2-1082: Adding a user control to a form throws exception if the control's code doesn't have a constructor without arguments.

Prevent ParserService.AllProjectContents from returning project contents multiple times.

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/trunk@2151 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/AddIns/DisplayBindings/FormsDesigner/Project/Src/Gui/CustomComponentsSideTab.cs

@@ -56,6 +56,13 @@ namespace ICSharpCode.FormsDesigner.Gui
 						continue;
 				}
 				foreach (IClass c in pc.Classes) {
+					if (!c.Methods.Exists(delegate (IMethod method) {
+					                      	return method.IsConstructor && method.IsPublic && method.Parameters.Count == 0;
+					                      }))
+					{
+						// do not include classes that don't have a public parameterless constructor
+						continue;
+					}
 					foreach (IClass subClass in c.ClassInheritanceTree) {
 						if (subClass.FullyQualifiedName == "System.Windows.Forms.Form") {
 							break; // is not a design component

src/Main/Base/Project/Src/Services/ParserService/ParserService.cs

@@ -86,12 +86,7 @@ namespace ICSharpCode.SharpDevelop
 		/// </summary>
 		public static IEnumerable<IProjectContent> AllProjectContentsWithReferences {
 			get {
-				foreach (IProjectContent pc in AllProjectContents) {
-					yield return pc;
-				}
-				foreach (IProjectContent pc in defaultProjectContentRegistry.GetLoadedProjectContents()) {
-					yield return pc;
-				}
+				return Linq.Distinct(Linq.Concat(AllProjectContents, defaultProjectContentRegistry.GetLoadedProjectContents()));
 			}
 		}
 		

src/Main/Base/Project/Src/Util/Linq.cs

@@ -104,5 +104,41 @@ namespace ICSharpCode.SharpDevelop
 			}
 			return count;
 		}
+		
+		/// <summary>
+		/// Concatenates the specified enumerables.
+		/// </summary>
+		public static IEnumerable<T> Concat<T>(params IEnumerable<T>[] inputs)
+		{
+			return Concat(inputs as IEnumerable<IEnumerable<T>>);
+		}
+		
+		/// <summary>
+		/// Concatenates the specified enumerables.
+		/// </summary>
+		public static IEnumerable<T> Concat<T>(IEnumerable<IEnumerable<T>> inputs)
+		{
+			foreach (IEnumerable<T> input in inputs) {
+				foreach (T element in input) {
+					yield return element;
+				}
+			}
+		}
+		
+		/// <summary>
+		/// Outputs distinct elements only, filtering all duplicates.
+		/// </summary>
+		public static IEnumerable<T> Distinct<T>(IEnumerable<T> input)
+		{
+			// store elements already seen
+			Dictionary<T, object> elements = new Dictionary<T, object>();
+			
+			foreach (T element in input) {
+				if (!elements.ContainsKey(element)) {
+					elements.Add(element, null);
+					yield return element;
+				}
+			}
+		}
 	}
 }