Fixed NullReferenceException when implicit reference (like Microsoft.VisualBasic in VB projects) cannot be loaded for code-completion.

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/trunk@1938 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/AddIns/BackendBindings/Boo/BooBinding/Project/Src/BooProject.cs

@@ -82,9 +82,9 @@ namespace Grunwald.BooBinding
 		{
 			ParseProjectContent pc = base.CreateProjectContent();
 			ReferenceProjectItem systemItem = new ReferenceProjectItem(this, "System");
-			pc.ReferencedContents.Add(ParserService.GetProjectContentForReference(systemItem));
+			pc.AddReferencedContent(ParserService.GetProjectContentForReference(systemItem));
 			ReferenceProjectItem booLangItem = new ReferenceProjectItem(this, typeof(Boo.Lang.Builtins).Assembly.Location);
-			pc.ReferencedContents.Add(ParserService.GetProjectContentForReference(booLangItem));
+			pc.AddReferencedContent(ParserService.GetProjectContentForReference(booLangItem));
 			if (BooCompilerPC == null) {
 				ReferenceProjectItem booCompilerItem = new ReferenceProjectItem(this, typeof(Boo.Lang.Compiler.AbstractAstAttribute).Assembly.Location);
 				BooCompilerPC = ParserService.GetProjectContentForReference(booCompilerItem);

src/AddIns/BackendBindings/VBNetBinding/Project/Src/Project/VBNetProject.cs

@@ -65,7 +65,7 @@ namespace VBNetBinding
 			ParseProjectContent pc = base.CreateProjectContent();
 			ReferenceProjectItem vbRef = new ReferenceProjectItem(this, "Microsoft.VisualBasic");
 			if (vbRef != null) {
-				pc.ReferencedContents.Add(ParserService.GetProjectContentForReference(vbRef));
+				pc.AddReferencedContent(ParserService.GetProjectContentForReference(vbRef));
 			}
 			MyNamespaceBuilder.BuildNamespace(this, pc);
 			return pc;

src/AddIns/Misc/MonoAddIn/Project/Src/MonoProjectContentRegistry.cs

@@ -24,7 +24,11 @@ namespace ICSharpCode.MonoAddIn
 			if (assemblyName != null && assemblyName.FileName != null) {
 				return CecilReader.LoadAssembly(assemblyName.FileName, this);
 			} else {
-				HostCallback.ShowAssemblyLoadError(itemFileName, itemInclude, "");
+				if (MonoToolLocationHelper.IsMonoInstalled) {
+					HostCallback.ShowAssemblyLoadError(itemFileName, itemInclude, "Could not find assembly in Mono's GAC.");
+				} else {
+					HostCallback.ShowAssemblyLoadError(itemFileName, itemInclude, "Could not find assembly in Mono's GAC - Mono is not installed.");
+				}
 				return null;
 			}
 		}

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

@@ -22,9 +22,7 @@ namespace ICSharpCode.SharpDevelop
 			newProjectContent.Language = project.LanguageProperties;
 			newProjectContent.initializing = true;
 			IProjectContent mscorlib = ParserService.GetRegistryForReference(new ReferenceProjectItem(project, "mscorlib")).Mscorlib;
-			if (mscorlib != null) {
-				newProjectContent.ReferencedContents.Add(mscorlib);
-			}
+			newProjectContent.AddReferencedContent(mscorlib);
 			return newProjectContent;
 		}
 		
@@ -67,10 +65,7 @@ namespace ICSharpCode.SharpDevelop
 		{
 			lock (ReferencedContents) {
 				ReferencedContents.Clear();
-				IProjectContent mscorlib = ParserService.GetRegistryForReference(new ReferenceProjectItem(project, "mscorlib")).Mscorlib;
-				if (mscorlib != null) {
-					ReferencedContents.Add(mscorlib);
-				}
+				AddReferencedContent(ParserService.GetRegistryForReference(new ReferenceProjectItem(project, "mscorlib")).Mscorlib);
 			}
 			// prevent adding event handler twice
 			ProjectService.ProjectItemAdded   -= OnProjectItemAdded;
@@ -98,12 +93,7 @@ namespace ICSharpCode.SharpDevelop
 		void AddReference(ReferenceProjectItem reference, bool updateInterDependencies)
 		{
 			try {
-				IProjectContent referencedContent = ParserService.GetProjectContentForReference(reference);
-				if (referencedContent != null) {
-					lock (this.ReferencedContents) {
-						this.ReferencedContents.Add(referencedContent);
-					}
-				}
+				AddReferencedContent(ParserService.GetProjectContentForReference(reference));
 				if (updateInterDependencies) {
 					UpdateReferenceInterDependencies();
 				}

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

@@ -501,7 +501,7 @@ namespace ICSharpCode.SharpDevelop
 			LoggingService.Info("Creating default project content");
 			//LoggingService.Debug("Stacktrace is:\n" + Environment.StackTrace);
 			defaultProjectContent = new DefaultProjectContent();
-			defaultProjectContent.ReferencedContents.Add(defaultProjectContentRegistry.Mscorlib);
+			defaultProjectContent.AddReferencedContent(defaultProjectContentRegistry.Mscorlib);
 			Thread t = new Thread(new ThreadStart(CreateDefaultProjectContentReferences));
 			t.IsBackground = true;
 			t.Priority = ThreadPriority.BelowNormal;
@@ -514,12 +514,7 @@ namespace ICSharpCode.SharpDevelop
 			IList<string> defaultReferences = AddInTree.BuildItems<string>("/SharpDevelop/Services/ParserService/SingleFileGacReferences", null, false);
 			foreach (string defaultReference in defaultReferences) {
 				ReferenceProjectItem item = new ReferenceProjectItem(null, defaultReference);
-				IProjectContent pc = ParserService.GetProjectContentForReference(item);
-				if (pc != null) {
-					lock (defaultProjectContent.ReferencedContents) {
-						defaultProjectContent.ReferencedContents.Add(pc);
-					}
-				}
+				defaultProjectContent.AddReferencedContent(ParserService.GetProjectContentForReference(item));
 			}
 			if (WorkbenchSingleton.Workbench != null) {
 				WorkbenchSingleton.Workbench.ActiveWorkbenchWindowChanged += delegate {

src/Main/ICSharpCode.SharpDevelop.Dom/Project/Src/ProjectContent/DefaultProjectContent.cs

@@ -898,6 +898,15 @@ namespace ICSharpCode.SharpDevelop.Dom
 		}
 		#endregion
 		
+		public void AddReferencedContent(IProjectContent pc)
+		{
+			if (pc != null) {
+				lock (this.ReferencedContents) {
+					this.ReferencedContents.Add(pc);
+				}
+			}
+		}
+		
 		public event EventHandler ReferencedContentsChanged;
 		
 		protected virtual void OnReferencedContentsChanged(EventArgs e)