SD2-775 - Null reference exception when creating a new folder. When a project directory is renamed/created the code now handles the case where there are IViewContents open with null filenames.

git-svn-id: svn://svn.sharpdevelop.net/sharpdevelop/branches/2.0@1325 1ccf3a8d-04fe-1044-b7c0-cef0b8235c61

src/Main/Base/Project/Src/Gui/Workbench/DefaultWorkbench.cs

@@ -380,7 +380,7 @@ namespace ICSharpCode.SharpDevelop.Gui
 		{
 			if (e.IsDirectory) {
 				foreach (IViewContent content in ViewContentCollection) {
-					if (content.FileName.StartsWith(e.SourceFile)) {
+					if (content.FileName != null && content.FileName.StartsWith(e.SourceFile)) {
 						content.FileName = e.TargetFile + content.FileName.Substring(e.SourceFile.Length);
 					}
 				}