Fix argument exception when using File->Save As and changing a file to a ASP.NET file extension when it was not previously.

src/AddIns/BackendBindings/AspNet.Mvc/Project/Src/Folding/CSharpRazorLanguageBinding.cs

@@ -13,5 +13,9 @@ namespace ICSharpCode.AspNet.Mvc.Folding
 				new RazorFoldGeneratorFactory(".cshtml"))
 		{
 		}
+		
+		public override string HighlightingSyntaxName {
+			get { return "C#/Razor"; }
+		}
 	}
 }

src/AddIns/BackendBindings/AspNet.Mvc/Project/Src/Folding/FoldGenerator.cs

@@ -20,6 +20,7 @@ namespace ICSharpCode.AspNet.Mvc.Folding
 			this.textEditor = textEditor;
 			this.foldParser = foldParser;
 			IsParseInformationFoldingEnabled = false;
+			this.textEditor.InstallFoldingManager();
 		}
 		
 		bool IsParseInformationFoldingEnabled {

src/AddIns/BackendBindings/AspNet.Mvc/Project/Src/Folding/HtmlLanguageBinding.cs

@@ -8,7 +8,7 @@ using ICSharpCode.SharpDevelop.Editor;
 
 namespace ICSharpCode.AspNet.Mvc.Folding
 {
-	public class HtmlLanguageBinding : DefaultLanguageBinding
+	public abstract class HtmlLanguageBinding : DefaultLanguageBinding
 	{
 		ITextEditorWithParseInformationFoldingFactory textEditorFactory;
 		IFoldGeneratorFactory foldGeneratorFactory;
@@ -30,6 +30,8 @@ namespace ICSharpCode.AspNet.Mvc.Folding
 			get { return LanguageProperties.None; }
 		}
 		
+		public abstract string HighlightingSyntaxName { get; }
+		
 		public override void Attach(ITextEditor editor)
 		{
 			Attach(textEditorFactory.CreateTextEditor(editor));
@@ -38,6 +40,7 @@ namespace ICSharpCode.AspNet.Mvc.Folding
 		void Attach(ITextEditorWithParseInformationFolding editor)
 		{
 			foldGenerator = foldGeneratorFactory.CreateFoldGenerator(editor);
+			editor.UpdateSyntaxHighlighting(HighlightingSyntaxName);
 		}
 		
 		public override void Detach()

src/AddIns/BackendBindings/AspNet.Mvc/Project/Src/Folding/ITextEditorWithParseInformationFolding.cs

@@ -13,6 +13,8 @@ namespace ICSharpCode.AspNet.Mvc.Folding
 		bool IsParseInformationFoldingEnabled { get; set; }
 		
 		void UpdateFolds(IEnumerable<NewFolding> folds);
+		void InstallFoldingManager();
 		string GetTextSnapshot();
+		void UpdateSyntaxHighlighting(string highlightingSyntaxName);
 	}
 }

src/AddIns/BackendBindings/AspNet.Mvc/Project/Src/Folding/TextEditorWithParseInformationFolding.cs

@@ -6,6 +6,7 @@ using System.Collections.Generic;
 using ICSharpCode.AvalonEdit;
 using ICSharpCode.AvalonEdit.AddIn;
 using ICSharpCode.AvalonEdit.Folding;
+using ICSharpCode.AvalonEdit.Highlighting;
 using ICSharpCode.SharpDevelop.Editor;
 using ICSharpCode.SharpDevelop.Editor.AvalonEdit;
 
@@ -20,10 +21,9 @@ namespace ICSharpCode.AspNet.Mvc.Folding
 		public TextEditorWithParseInformationFolding(ITextEditor textEditor)
 		{
 			this.textEditor = textEditor;
-			InstallFoldingManager();
 		}
 		
-		void InstallFoldingManager()
+		public void InstallFoldingManager()
 		{
 			var textEditorAdapter = textEditor as AvalonEditTextEditorAdapter;
 			if (textEditorAdapter != null) {
@@ -73,5 +73,26 @@ namespace ICSharpCode.AspNet.Mvc.Folding
 		{
 			FoldingManager.Uninstall(foldingManager);
 		}
+		
+		public void UpdateSyntaxHighlighting(string name)
+		{
+			if (!IsUsingSyntaxhighlighting(name)) {
+				ChangeSyntaxHighlighting(name);
+			}
+		}
+		
+	    bool IsUsingSyntaxhighlighting(string name)
+		{
+			IHighlightingDefinition highlighting = CodeEditorView.SyntaxHighlighting;
+			if (highlighting != null) {
+				return highlighting.Name == name;
+			}
+			return false;
+		}
+		
+		void ChangeSyntaxHighlighting(string name)
+		{
+			CodeEditorView.SyntaxHighlighting =	HighlightingManager.Instance.GetDefinition(name);
+		}
 	}
 }

src/AddIns/BackendBindings/AspNet.Mvc/Project/Src/Folding/VisualBasicRazorLanguageBinding.cs

@@ -13,5 +13,9 @@ namespace ICSharpCode.AspNet.Mvc.Folding
 				new RazorFoldGeneratorFactory(".vbhtml"))
 		{
 		}
+		
+		public override string HighlightingSyntaxName {
+			get { return "VBNET/Razor"; }
+		}
 	}
 }

src/AddIns/BackendBindings/AspNet.Mvc/Project/Src/Folding/WebFormsLanguageBinding.cs

@@ -21,5 +21,9 @@ namespace ICSharpCode.AspNet.Mvc.Folding
 			: base(textEditorFactory, foldGeneratorFactory)
 		{
 		}
+		
+		public override string HighlightingSyntaxName {
+			get { return "ASP/XHTML"; }
+		}
 	}
 }

src/AddIns/BackendBindings/AspNet.Mvc/Test/Src/Folding/FoldGeneratorTests.cs

@@ -76,6 +76,29 @@ namespace AspNet.Mvc.Tests.Folding
 			Assert.IsTrue(fakeTextEditor.IsParseInformationFoldingEnabled);
 		}
 		
+		[Test]
+		public void Constructor_TextEditor_InstallFoldingManagerIsInstalled()
+		{
+			CreateFakeTextEditor();
+			CreateFoldGenerator();
+			
+			fakeTextEditor.AssertWasCalled(textEditor => textEditor.InstallFoldingManager());
+		}
+		
+		[Test]
+		public void Constructor_TextEditor_InstallFoldingManagerIsInstalledAfterParseInfoIsDisabled()
+		{
+			CreateFakeTextEditor();
+			fakeTextEditor.IsParseInformationFoldingEnabled = true;
+			bool parseInfoEnabled = true;
+			fakeTextEditor
+				.Stub(t => t.InstallFoldingManager())
+				.Do((Action)delegate { parseInfoEnabled = fakeTextEditor.IsParseInformationFoldingEnabled; });
+			CreateFoldGenerator();
+			
+			Assert.IsFalse(parseInfoEnabled);
+		}
+		
 		[Test]
 		public void GenerateFolds_MethodCalled_FoldsFromFoldParserUsedToUpdateTextEditor()
 		{