出于不明原因，使用TextRange方法出错

Question

我试图在wpf中的richtextbox中突出显示一个TextRange，但是我不断得到关于无效参数的错误，即使我非常有信心这个参数是不正确的。我理解如何阻止程序崩溃，但是如果抛出这个ArgumentException，那么我的程序不会按照我的意愿行事。

下面是GetAllWordRanges方法的代码。

private static IEnumerable<TextRange> GetAllWordRanges(FlowDocument document, List<string> keywords)
{
    foreach (string keyword in keywords)
    {
        TextPointer pointer = document.ContentStart;
        while (pointer != null)
        {
            if (pointer.GetPointerContext(LogicalDirection.Forward) == TextPointerContext.Text)
            {
                string textRun = pointer.GetTextInRun(LogicalDirection.Forward);
                MatchCollection matches = Regex.Matches(textRun, keyword);
                foreach (Match match in matches)
                {
                    int startIndex = match.Index;
                    int length = match.Length;
                    TextPointer start = pointer.GetPositionAtOffset(startIndex);
                    TextPointer end = start.GetPositionAtOffset(length);
                    yield return new TextRange(start, end);
                }
            }

            pointer = pointer.GetNextContextPosition(LogicalDirection.Forward);
        }
    }
}

例外细节：

System.ArgumentException was unhandled
  HResult=-2147024809
  Message='SolidBrush' parameter type is not valid for formatting property 'Background'.
Parameter name: value
  Source=PresentationFramework
  ParamName=value
  StackTrace:
       at System.Windows.Documents.TextRange.ApplyPropertyValue(DependencyProperty formattingProperty, Object value, Boolean applyToParagraphs, PropertyValueAction propertyValueAction)
       at System.Windows.Documents.TextRange.ApplyPropertyValue(DependencyProperty formattingProperty, Object value)
       at EmailCheckerWPF.TextAnalyser.turnTextRed(RichTextBox TextBox, List`1 Keywords) in c:\Users\Luke\Documents\Caimbridge comp\EmailCheckerWPF\TextAnalyser.cs:line 138
       at EmailCheckerWPF.MainWindow.AnalyseButton_Click(Object sender, RoutedEventArgs e) in c:\Users\Luke\Documents\Caimbridge comp\EmailCheckerWPF\MainWindow.xaml.cs:line 50
       at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
       at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
       at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
       at System.Windows.UIElement.RaiseEvent(RoutedEventArgs e)
       at System.Windows.Controls.Primitives.ButtonBase.OnClick()
       at System.Windows.Controls.Button.OnClick()
       at System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e)
       at System.Windows.UIElement.OnMouseLeftButtonUpThunk(Object sender, MouseButtonEventArgs e)
       at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
       at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
       at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
       at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
       at System.Windows.UIElement.ReRaiseEventAs(DependencyObject sender, RoutedEventArgs args, RoutedEvent newEvent)
       at System.Windows.UIElement.OnMouseUpThunk(Object sender, MouseButtonEventArgs e)
       at System.Windows.Input.MouseButtonEventArgs.InvokeEventHandler(Delegate genericHandler, Object genericTarget)
       at System.Windows.RoutedEventArgs.InvokeHandler(Delegate handler, Object target)
       at System.Windows.RoutedEventHandlerInfo.InvokeHandler(Object target, RoutedEventArgs routedEventArgs)
       at System.Windows.EventRoute.InvokeHandlersImpl(Object source, RoutedEventArgs args, Boolean reRaised)
       at System.Windows.UIElement.RaiseEventImpl(DependencyObject sender, RoutedEventArgs args)
       at System.Windows.UIElement.RaiseTrustedEvent(RoutedEventArgs args)
       at System.Windows.UIElement.RaiseEvent(RoutedEventArgs args, Boolean trusted)
       at System.Windows.Input.InputManager.ProcessStagingArea()
       at System.Windows.Input.InputManager.ProcessInput(InputEventArgs input)
       at System.Windows.Input.InputProviderSite.ReportInput(InputReport inputReport)
       at System.Windows.Interop.HwndMouseInputProvider.ReportInput(IntPtr hwnd, InputMode mode, Int32 timestamp, RawMouseActions actions, Int32 x, Int32 y, Int32 wheel)
       at System.Windows.Interop.HwndMouseInputProvider.FilterMessage(IntPtr hwnd, WindowMessage msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at System.Windows.Interop.HwndSource.InputFilterMessage(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at MS.Win32.HwndWrapper.WndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam, Boolean& handled)
       at MS.Win32.HwndSubclass.DispatcherCallbackOperation(Object o)
       at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
       at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
       at System.Windows.Threading.Dispatcher.LegacyInvokeImpl(DispatcherPriority priority, TimeSpan timeout, Delegate method, Object args, Int32 numArgs)
       at MS.Win32.HwndSubclass.SubclassWndProc(IntPtr hwnd, Int32 msg, IntPtr wParam, IntPtr lParam)
       at MS.Win32.UnsafeNativeMethods.DispatchMessage(MSG& msg)
       at System.Windows.Threading.Dispatcher.PushFrameImpl(DispatcherFrame frame)
       at System.Windows.Threading.Dispatcher.PushFrame(DispatcherFrame frame)
       at System.Windows.Threading.Dispatcher.Run()
       at System.Windows.Application.RunDispatcher(Object ignore)
       at System.Windows.Application.RunInternal(Window window)
       at System.Windows.Application.Run(Window window)
       at System.Windows.Application.Run()
       at EmailCheckerWPF.App.Main() in c:\Users\Luke\Documents\Caimbridge comp\EmailCheckerWPF\obj\Debug\App.g.cs:line 0
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: 

Answer 1

在winforms的旧时代，我们有GDI +类型用于渲染UI。

然后是WPF。这是对桌面应用程序的UI堆栈的完全重写。除了创建不同版本的UI元素（System.Windows.Forms.Window与System.Windows.Controls.Window）之外，还重写了渲染堆栈和相关类。明智与否，许多以前的模式都是在这次重写中复制的。

Winforms将继续留在不明智的框架中，偶然发现并导致自己的恶作剧。由于我们现在有两个（不兼容）版本的相同模式在框架中共存，我们也可能遗憾地陷入神层WPF开发人员。

最常见的陷阱之一是导入System.Drawing命名空间。 WPF开发人员的等效实际上是System.Windows.Media。两个名称空间都包含许多非常相似但不兼容的类型。如果你不小心（如果你没有得到好的异常消息，告诉你所需的效果类型的命名空间与你实际使用的mothereffign类型的命名空间），你将using错误的命名空间并开始围绕GDI +画笔。

小心，WPF开发人员。确保你总是使用WPF堆栈！ Winforms适用于穷人和未受过教育的人。我们现在不想与这些人交往吗？