使用Windows范围的Beta UTF-8支持功能时，在Winforms中调整RTF的错误

Question

我想我已经在Windows或.NET中发现了一个错误，正在寻找解决方法。

要重现该问题，请首先启用Windows功能“ Beta：使用Unicode UTF-8进行全球语言支持”。

您可能需要重启机器。

现在，只需在Winforms / C＃中创建两个RichTextBox组件，然后添加事件：

    private void richTextBox1_TextChanged(object sender, EventArgs e)
    {
        string s = richTextBox1.Rtf;
        richTextBox2.Rtf = s;
    }

最后，运行该程序，只需在第一个RichTextBox中键入一些内容，当它尝试写入时就会崩溃，并显示消息“文件格式无效” richTextBox2.Rtf。如果Windows功能“测试版：将Unicode UTF-8用于全球语言支持”被禁用，则不会崩溃。

我在这里考虑两个潜在的解决方法：

1：以某种方式在C＃应用程序中禁用了整个“测试版：使用Unicode UTF-8进行全球语言支持”功能，并假装从未启用过该功能。

2：在调整另一个RichTextBox的RTF之前，以某种方式编辑RTF字符串以符合新RTF应该具有的未知要求。考虑到第一个RichTextBox应该具有完全相同的RTF，这似乎是违反直觉的，但是无论如何...

---

************* Exception Text **************
System.ArgumentException: File format is not valid.
at System.Windows.Forms.RichTextBox.StreamIn(Stream data, Int32 flags)
at System.Windows.Forms.RichTextBox.StreamIn(String str, Int32 flags)
at System.Windows.Forms.RichTextBox.set_Rtf(String value)
at unicodeTesting.Form1.richTextBox1_TextChanged(Object sender, EventArgs e) in D:\Code\c#\_tests\unicodeTesting\Form1.cs:line 30
at System.Windows.Forms.Control.OnTextChanged(EventArgs e)
at System.Windows.Forms.TextBoxBase.OnTextChanged(EventArgs e)
at System.Windows.Forms.TextBoxBase.WmReflectCommand(Message& m)
at System.Windows.Forms.TextBoxBase.WndProc(Message& m)
at System.Windows.Forms.RichTextBox.WmReflectCommand(Message& m)
at System.Windows.Forms.RichTextBox.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

Answer 1

Microsoft开源了WinForms库，因此您可以自己深入研究源代码：

https://github.com/dotnet/winforms/tree/master/src/System.Windows.Forms/src/System/Windows/Forms

StreamIn方法位于https://github.com/dotnet/winforms/blob/master/src/System.Windows.Forms/src/System/Windows/Forms/RichTextBox.cs的第3140行：

 private void StreamIn(string str, int flags)
    {
        if (str.Length == 0)
        {
            // Destroy the selection if callers was setting
            // selection text
            //
            if ((RichTextBoxConstants.SFF_SELECTION & flags) != 0)
            {
                SendMessage(Interop.WindowMessages.WM_CLEAR, 0, 0);
                ProtectedError = false;
                return;
            }
            // WM_SETTEXT is allowed even if we have protected text
            //
            SendMessage(Interop.WindowMessages.WM_SETTEXT, 0, "");
            return;
        }

        // Rather than work only some of the time with null characters,
        // we're going to be consistent and never work with them.
        int nullTerminatedLength = str.IndexOf((char)0);
        if (nullTerminatedLength != -1)
        {
            str = str.Substring(0, nullTerminatedLength);
        }

        // get the string into a byte array
        byte[] encodedBytes;
        if ((flags & RichTextBoxConstants.SF_UNICODE) != 0)
        {
            encodedBytes = Encoding.Unicode.GetBytes(str);
        }
        else
        {
            encodedBytes = Encoding.Default.GetBytes(str);
        }
        editStream = new MemoryStream(encodedBytes.Length);
        editStream.Write(encodedBytes, 0, encodedBytes.Length);
        editStream.Position = 0;
        StreamIn(editStream, flags);
    }

    private void StreamIn(Stream data, int flags)
    {
        // clear out the selection only if we are replacing all the text
        //
        if ((flags & RichTextBoxConstants.SFF_SELECTION) == 0)
        {
            NativeMethods.CHARRANGE cr = new NativeMethods.CHARRANGE();
            UnsafeNativeMethods.SendMessage(new HandleRef(this, Handle), Interop.EditMessages.EM_EXSETSEL, 0, cr);
        }

        try
        {
            editStream = data;
            Debug.Assert(data != null, "StreamIn passed a null stream");

            // If SF_RTF is requested then check for the RTF tag at the start
            // of the file.  We don't load if the tag is not there
            // 
            if ((flags & RichTextBoxConstants.SF_RTF) != 0)
            {
                long streamStart = editStream.Position;
                byte[] bytes = new byte[SZ_RTF_TAG.Length];
                editStream.Read(bytes, (int)streamStart, SZ_RTF_TAG.Length);
                string str = Encoding.Default.GetString(bytes);
                if (!SZ_RTF_TAG.Equals(str))
                {
                    throw new ArgumentException(SR.InvalidFileFormat);
                }

                // put us back at the start of the file
                editStream.Position = streamStart;
            }

            int cookieVal = 0;
            // set up structure to do stream operation
            NativeMethods.EDITSTREAM es = new NativeMethods.EDITSTREAM();
            if ((flags & RichTextBoxConstants.SF_UNICODE) != 0)
            {
                cookieVal = INPUT | UNICODE;
            }
            else
            {
                cookieVal = INPUT | ANSI;
            }
            if ((flags & RichTextBoxConstants.SF_RTF) != 0)
            {
                cookieVal |= RTF;
            }
            else
            {
                cookieVal |= TEXTLF;
            }
            es.dwCookie = (IntPtr)cookieVal;
            es.pfnCallback = new NativeMethods.EditStreamCallback(EditStreamProc);

            // gives us TextBox compatible behavior, programatic text change shouldn't
            // be limited...
            //
            SendMessage(Interop.EditMessages.EM_EXLIMITTEXT, 0, int.MaxValue);



            // go get the text for the control
            // Needed for 64-bit
            if (IntPtr.Size == 8)
            {
                NativeMethods.EDITSTREAM64 es64 = ConvertToEDITSTREAM64(es);
                UnsafeNativeMethods.SendMessage(new HandleRef(this, Handle), Interop.EditMessages.EM_STREAMIN, flags, es64);

                //Assign back dwError value
                es.dwError = GetErrorValue64(es64);
            }
            else
            {
                UnsafeNativeMethods.SendMessage(new HandleRef(this, Handle), Interop.EditMessages.EM_STREAMIN, flags, es);
            }

            UpdateMaxLength();

            // If we failed to load because of protected
            // text then return protect event was fired so no
            // exception is required for the the error
            if (GetProtectedError())
            {
                return;
            }

            if (es.dwError != 0)
            {
                throw new InvalidOperationException(SR.LoadTextError);
            }

            // set the modify tag on the control
            SendMessage(Interop.EditMessages.EM_SETMODIFY, -1, 0);

            // EM_GETLINECOUNT will cause the RichTextBoxConstants to recalculate its line indexes
            SendMessage(Interop.EditMessages.EM_GETLINECOUNT, 0, 0);


        }
        finally
        {
            // release any storage space held.
            editStream = null;
        }
    }

它看起来确实像是个错误，并且由于它是测试版，因此最好的做法是将其记录在Microsoft的https://developercommunity.visualstudio.com上。

如果用库中的代码替换RichTextBox控件类，则可以在以下位置查看发生错误的行：

System.Windows.Forms.RichTextBox.StreamIn(Stream data, Int32 flags)

更新：

这实际上是一个已知问题， https://social.msdn.microsoft.com/Forums/en-US/28940162-5f7b-4687-af19-1eeef90d3963/richtextboxrtf-setter-throwing-systemargumentexception-file-format-is-not -valid-in-windows-forum = winforms

已经向Microsooft报告过：https : //developercommunity.visualstudio.com/content/problem/544623/issue-caused-by-unicode-utf-8-for-world-wide-langu.html

MSFT的Kyle Wang已将其范围缩小到一个操作系统问题：

PC1（OS Build .437可以重现该问题）：

信封：

测试：

PC2（操作系统内部版本.348无法重现该问题）：

信封：

测试：