在 WinForms RichTextBox 中重置 RTF 格式而不丢弃其文本？

我正在尝试“重置” RichTextBox（WinForms，而不是 WPF）中的格式。我以前使用过

richTextBox.Text = richTextBox.Text;

然而，这似乎突然让我失望了。现在无论我设置什么richTextBox.Text到，它保留了一些 rtf 格式。

我试过了

richTextBox.Rtf = richTextBox.Text;

然而，这抱怨格式不正确。一定有更好的方法来做到这一点。 （当然，选择整个内容，然后重置背景颜色、前景色和字体是可行的，但这会导致闪烁，因为选择整个内容然后取消选择，而且速度较慢并且需要更多代码。）任何想法？

编辑： 我已经让它工作了：

string tempTxt = richTextBox.Text;
richTextBox.Clear();
richTextBox.Text = tempTxt;

但一定有更好的方法，对吗？

编辑2： 需要明确的是，我希望删除所有格式，同时保留文本。看起来第一次编辑中的代码将会发布，除非其他人有更有效/更好的编码方式。

Edit 3:

richTextBox.Text = richTextBox.Text.ToString();

似乎不起作用，因为它仍然没有清除所有格式。我不喜欢上面第一个编辑中的方法的原因是，当它清除文本框然后重新输入文本时，它会使文本框“闪烁”。似乎应该简单地有一个 richTextBox.ResetFormatting() 方法，或者某种访问相同功能的方法，因为 Clear() 方法显然（没有双关语）除了简单地清除所有文本之外还执行某种格式重置。

总结一下：

有没有一种方法（如果是的话，它是什么）可以重置 RichTextBox 中文本的格式，而无需像上面的示例那样清除文本（因为这会产生不需要的闪烁）？

遗憾的是，我已尽最大努力将其精简为仅所需的代码。它仍然很大，但它会起作用。 .Net 中的 RichTextBox api 非常有限，要做任何事情你几乎都必须进入 Win32 库。我围绕这个东西构建了一个完整的库，这样我就可以切换粗体并确定粗体是否确实在整个选择中设置。

Usage:

RichTextBox te = ...;
te.ClearAllFormatting(new Font("Microsoft Sans Serif", 8.25f));

大量代码：

static class RichTextExtensions
{
    public static void ClearAllFormatting(this RichTextBox te, Font font)
    {
        CHARFORMAT2 fmt = new CHARFORMAT2();

        fmt.cbSize = Marshal.SizeOf(fmt);
        fmt.dwMask = CFM_ALL2;
        fmt.dwEffects = CFE_AUTOCOLOR | CFE_AUTOBACKCOLOR;
        fmt.szFaceName = font.FontFamily.Name;

        double size = font.Size;
        size /= 72;//logical dpi (pixels per inch)
        size *= 1440.0;//twips per inch

        fmt.yHeight = (int)size;//165
        fmt.yOffset = 0;
        fmt.crTextColor = 0;
        fmt.bCharSet = 1;// DEFAULT_CHARSET;
        fmt.bPitchAndFamily = 0;// DEFAULT_PITCH;
        fmt.wWeight = 400;// FW_NORMAL;
        fmt.sSpacing = 0;
        fmt.crBackColor = 0;
        //fmt.lcid = ???
        fmt.dwMask &= ~CFM_LCID;//don't know how to get this...
        fmt.dwReserved = 0;
        fmt.sStyle = 0;
        fmt.wKerning = 0;
        fmt.bUnderlineType = 0;
        fmt.bAnimation = 0;
        fmt.bRevAuthor = 0;
        fmt.bReserved1 = 0;

        SendMessage(te.Handle, EM_SETCHARFORMAT, SCF_ALL, ref fmt);
    }

    private const UInt32 WM_USER = 0x0400;
    private const UInt32 EM_GETCHARFORMAT = (WM_USER + 58);
    private const UInt32 EM_SETCHARFORMAT = (WM_USER + 68);
    private const UInt32 SCF_ALL = 0x0004;
    private const UInt32 SCF_SELECTION = 0x0001;

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
    static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, UInt32 wParam, ref CHARFORMAT2 lParam);

    [StructLayout(LayoutKind.Sequential, Pack = 4, CharSet = CharSet.Auto)]
    struct CHARFORMAT2
    {
        public int cbSize;
        public uint dwMask;
        public uint dwEffects;
        public int yHeight;
        public int yOffset;
        public int crTextColor;
        public byte bCharSet;
        public byte bPitchAndFamily;
        [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 32)]
        public string szFaceName;
        public short wWeight;
        public short sSpacing;
        public int crBackColor;
        public int lcid;
        public int dwReserved;
        public short sStyle;
        public short wKerning;
        public byte bUnderlineType;
        public byte bAnimation;
        public byte bRevAuthor;
        public byte bReserved1;
    }

    #region CFE_
    // CHARFORMAT effects 
    const UInt32 CFE_BOLD = 0x0001;
    const UInt32 CFE_ITALIC = 0x0002;
    const UInt32 CFE_UNDERLINE = 0x0004;
    const UInt32 CFE_STRIKEOUT = 0x0008;
    const UInt32 CFE_PROTECTED = 0x0010;
    const UInt32 CFE_LINK = 0x0020;
    const UInt32 CFE_AUTOCOLOR = 0x40000000;            // NOTE: this corresponds to 
    // CFM_COLOR, which controls it 
    // Masks and effects defined for CHARFORMAT2 -- an (*) indicates
    // that the data is stored by RichEdit 2.0/3.0, but not displayed
    const UInt32 CFE_SMALLCAPS = CFM_SMALLCAPS;
    const UInt32 CFE_ALLCAPS = CFM_ALLCAPS;
    const UInt32 CFE_HIDDEN = CFM_HIDDEN;
    const UInt32 CFE_OUTLINE = CFM_OUTLINE;
    const UInt32 CFE_SHADOW = CFM_SHADOW;
    const UInt32 CFE_EMBOSS = CFM_EMBOSS;
    const UInt32 CFE_IMPRINT = CFM_IMPRINT;
    const UInt32 CFE_DISABLED = CFM_DISABLED;
    const UInt32 CFE_REVISED = CFM_REVISED;

    // CFE_AUTOCOLOR and CFE_AUTOBACKCOLOR correspond to CFM_COLOR and
    // CFM_BACKCOLOR, respectively, which control them
    const UInt32 CFE_AUTOBACKCOLOR = CFM_BACKCOLOR;
    #endregion
    #region CFM_
    // CHARFORMAT masks 
    const UInt32 CFM_BOLD = 0x00000001;
    const UInt32 CFM_ITALIC = 0x00000002;
    const UInt32 CFM_UNDERLINE = 0x00000004;
    const UInt32 CFM_STRIKEOUT = 0x00000008;
    const UInt32 CFM_PROTECTED = 0x00000010;
    const UInt32 CFM_LINK = 0x00000020;         // Exchange hyperlink extension 
    const UInt32 CFM_SIZE = 0x80000000;
    const UInt32 CFM_COLOR = 0x40000000;
    const UInt32 CFM_FACE = 0x20000000;
    const UInt32 CFM_OFFSET = 0x10000000;
    const UInt32 CFM_CHARSET = 0x08000000;

    const UInt32 CFM_SMALLCAPS = 0x0040;            // (*)  
    const UInt32 CFM_ALLCAPS = 0x0080;          // Displayed by 3.0 
    const UInt32 CFM_HIDDEN = 0x0100;           // Hidden by 3.0 
    const UInt32 CFM_OUTLINE = 0x0200;          // (*)  
    const UInt32 CFM_SHADOW = 0x0400;           // (*)  
    const UInt32 CFM_EMBOSS = 0x0800;           // (*)  
    const UInt32 CFM_IMPRINT = 0x1000;          // (*)  
    const UInt32 CFM_DISABLED = 0x2000;
    const UInt32 CFM_REVISED = 0x4000;

    const UInt32 CFM_BACKCOLOR = 0x04000000;
    const UInt32 CFM_LCID = 0x02000000;
    const UInt32 CFM_UNDERLINETYPE = 0x00800000;        // Many displayed by 3.0 
    const UInt32 CFM_WEIGHT = 0x00400000;
    const UInt32 CFM_SPACING = 0x00200000;      // Displayed by 3.0 
    const UInt32 CFM_KERNING = 0x00100000;      // (*)  
    const UInt32 CFM_STYLE = 0x00080000;        // (*)  
    const UInt32 CFM_ANIMATION = 0x00040000;        // (*)  
    const UInt32 CFM_REVAUTHOR = 0x00008000;

    const UInt32 CFE_SUBSCRIPT = 0x00010000;        // Superscript and subscript are 
    const UInt32 CFE_SUPERSCRIPT = 0x00020000;      //  mutually exclusive           

    const UInt32 CFM_SUBSCRIPT = (CFE_SUBSCRIPT | CFE_SUPERSCRIPT);
    const UInt32 CFM_SUPERSCRIPT = CFM_SUBSCRIPT;

    // CHARFORMAT "ALL" masks
    const UInt32 CFM_EFFECTS = (CFM_BOLD | CFM_ITALIC | CFM_UNDERLINE | CFM_COLOR |
                         CFM_STRIKEOUT | CFE_PROTECTED | CFM_LINK);
    const UInt32 CFM_ALL = (CFM_EFFECTS | CFM_SIZE | CFM_FACE | CFM_OFFSET | CFM_CHARSET);

    const UInt32 CFM_EFFECTS2 = (CFM_EFFECTS | CFM_DISABLED | CFM_SMALLCAPS | CFM_ALLCAPS
                        | CFM_HIDDEN | CFM_OUTLINE | CFM_SHADOW | CFM_EMBOSS
                        | CFM_IMPRINT | CFM_DISABLED | CFM_REVISED
                        | CFM_SUBSCRIPT | CFM_SUPERSCRIPT | CFM_BACKCOLOR);

    const UInt32 CFM_ALL2 = (CFM_ALL | CFM_EFFECTS2 | CFM_BACKCOLOR | CFM_LCID
                        | CFM_UNDERLINETYPE | CFM_WEIGHT | CFM_REVAUTHOR
                        | CFM_SPACING | CFM_KERNING | CFM_STYLE | CFM_ANIMATION);
    #endregion
}

你还问更多吗？

我通过一个小型实用程序类使用其中的大部分内容，该实用程序类包装了所有样式和字体更改。这样您可以更改字体大小而不更改字体名称等。

class RichTextStyle
{   
    private readonly Control _textEdit;
    private readonly CHARFORMAT2 _charFormat;

    public RichTextStyle(RichTextBox te)
    {
        _textEdit = te;
        _charFormat = new CHARFORMAT2();
        _charFormat.cbSize = Marshal.SizeOf(_charFormat);
        SendMessage(te.Handle, EM_GETCHARFORMAT, SCF_SELECTION, ref _charFormat);
    }

    private void SetEffect(UInt32 mask, UInt32 effect, bool valid)
    {
        CHARFORMAT2 fmt = new CHARFORMAT2();
        fmt.cbSize = Marshal.SizeOf(fmt);
        fmt.dwMask = mask;
        fmt.dwEffects = valid ? effect : 0;
        SendMessage(_textEdit.Handle, EM_SETCHARFORMAT, SCF_SELECTION, ref fmt);
    }

    private bool GetEffect(UInt32 mask, UInt32 effect)
    {
        return (0 != (_charFormat.dwMask & mask)) && (0 != (_charFormat.dwEffects & effect));
    }

    public bool Bold { get { return GetEffect(CFM_BOLD, CFE_BOLD); } set { SetEffect(CFM_BOLD, CFE_BOLD, value); } }
    public bool Italic { get { return GetEffect(CFM_ITALIC, CFE_ITALIC); } set { SetEffect(CFM_ITALIC, CFE_ITALIC, value); } }

    // ... etc ... etc ... you get the idea.