System.Windows.Forms.FileDialog.AddFilterExtension C# (CSharp) Method

		bool AddFilterExtension (string fileName)
		{
			if (fileDialogType == FileDialogType.OpenFileDialog) {
				if (DefaultExt.Length == 0)
					return true;

				if (checkFileExists) {
					// if CheckFileExists is true, only add filter extension if
					// file with DefaultExt does not exist
					string fullFileName = fileName + "." + DefaultExt;
					return !File.Exists (fullFileName);
				} else {
					// if CheckFileExists is false, only add filter extension
					// if specified file does not exist
					return !File.Exists (fileName);
				}
			}

			return true;
		}