如何在Richtextbox的每一行的开头添加一个字符

Question

我正在做一个应用程序，如果你点击按钮，它会为每个选定的行添加一个特定的字符。例如在Richtextbox中的每一行中添加“//”并将文本着色为红色，这就像Visual Studio中的注释功能

我试过了，但是没用

private void toolStripButton1_Click(object sender, EventArgs e)
    {
        int firstCharPosition = richTextBox1.GetFirstCharIndexOfCurrentLine();
        int lineNumber = richTextBox1.GetLineFromCharIndex(firstCharPosition);
        int lastCharPosition = richTextBox1.GetFirstCharIndexFromLine(lineNumber + 1);

        if (richTextBox1.SelectionLength > 0)
        {
            richTextBox1.SelectionColor = Color.Red;
            richTextBox1.SelectedText = "//" + richTextBox1.SelectedText.ToString();
        }
        else
        {
            richTextBox1.Select(firstCharPosition, lastCharPosition - firstCharPosition);
            richTextBox1.SelectionColor = Color.Red;
            richTextBox1.SelectedText = "//" + richTextBox1.SelectedText.ToString();
        }
    }

请大家帮帮我，谢谢！

Answer 1

if (richTextBox1.Text.Length > 0 && richTextBox1.SelectionLength >= 0)
    {
        string[] lines = richTextBox1.Text.Split(new string[] { Environment.NewLine, "\n", "\r", "\r\n" }, StringSplitOptions.RemoveEmptyEntries);
        Color normalColor = Color.Black, commentColor = Color.Red;
        int selStart = richTextBox1.SelectionStart, selEnd = selStart + richTextBox1.SelectionLength,
        startLine = -1, endLine = -1, lineSum = 0, k = 0;

        for (k = 0; k < lines.Length; k++)
            if (startLine == -1)
            {
                if ((lineSum += lines[k].Length + 1) > selStart)
                {
                    startLine = k;
                    if (selEnd <= lineSum) endLine = k;
                }
            }
            else if (endLine == -1)
            {
                if ((lineSum += lines[k].Length + 1) >= selEnd)
                    endLine = k;
            }
            else break;

        for (int i = 0; i < lines.Length; i++)
            lines[i] = (i >= startLine && i <= endLine ? "//" : "") + lines[i];

        richTextBox1.Text = "";
        richTextBox1.SelectionStart = 0;
        for (int i = 0; i < lines.Length; i++)
        {
            richTextBox1.SelectionStart = richTextBox1.Text.Length;
            richTextBox1.SelectionColor = lines[i].TrimStart().StartsWith("//") ? commentColor : normalColor;
            richTextBox1.SelectedText = lines[i] += (i == lines.Length - 1 ? "" : "\r\n");
        }

        int selectStarIndx = richTextBox1.GetFirstCharIndexFromLine(startLine), selectEndIndx = richTextBox1.GetFirstCharIndexFromLine(endLine + 1);
        if (selectEndIndx == -1) selectEndIndx = richTextBox1.Text.Length;

        richTextBox1.Select(selectStarIndx, selectEndIndx - selectStarIndx);
        richTextBox1.Focus();
    }

Answer 2

正确操作RichTextBox比更改Text要复杂一些。这是一个可以帮助您的代码示例。

请注意，它永远不会直接更改 Text，因此它不会弄乱以前的格式，并且它会尝试恢复选择。

它允许您独立注释掉几个部分。它从TextBox 获取注释字符串进行测试，然后恢复为Black..

// get all line numbers that belong to the selection
List<int> getSelectedLines(RichTextBox RTB)
{
    List<int> lines = new List<int>();

    int sStart = RTB.SelectionStart;
    int sEnd = RTB.SelectionLength + sStart;

    int line1 = RTB.GetLineFromCharIndex(sStart);
    int line2 = RTB.GetLineFromCharIndex(sEnd);

    for (int l = line1; l <= line2; l++) lines.Add(l);
    return lines;

}

// prefix a line with a string
void prependLine(RichTextBox RTB, int line, string s)
{
    int sStart = RTB.SelectionStart;
    int sLength = RTB.SelectionLength;

    RTB.SelectionStart = RTB.GetFirstCharIndexFromLine(line);
    RTB.SelectionLength = 0;
    RTB.SelectedText = s;

    RTB.SelectionStart = sStart;
    RTB.SelectionLength = sLength;
}

// color one whole line
void colorLine(RichTextBox RTB, int line, Color c)
{
    int sStart = RTB.SelectionStart;
    int sLength = RTB.SelectionLength;

    RTB.SelectionStart = RTB.GetFirstCharIndexFromLine(line);
    RTB.SelectionLength = RTB.Lines[line].Length; ;
    RTB.SelectionColor = c;

    RTB.SelectionStart = sStart;
    RTB.SelectionLength = sLength;

}

// additional function, may come handy..
void trimLeftLine(RichTextBox RTB, int line, int length)
{
    int sStart = RTB.SelectionStart;
    int sLength = RTB.SelectionLength;

    RTB.SelectionStart = RTB.GetFirstCharIndexFromLine(line);
    RTB.SelectionLength = length;
    RTB.Cut();

    RTB.SelectionStart = sStart;
    RTB.SelectionLength = 0;
}

// remove a string token from the start of a line
void trimLeftLine(RichTextBox RTB, int line, string token)
{
    int sStart = RTB.SelectionStart;
    int sLength = RTB.SelectionLength;

    RTB.SelectionStart = RTB.GetFirstCharIndexFromLine(line);
    RTB.SelectionLength = token.Length;
    if (RTB.SelectedText == token) RTB.Cut();

    RTB.SelectionStart = sStart;
    RTB.SelectionLength = 0;
}

这是评论按钮：

private void button1_Click(object sender, EventArgs e)
{
    List<int> lines = getSelectedLines(richTextBox1);

    foreach (int l in lines) prependLine(richTextBox1, l, tb_comment.Text);
    foreach (int l in lines) colorLine(richTextBox1, l, Color.Firebrick);

}

这是取消注释按钮：

private void button2_Click(object sender, EventArgs e)
{
    List<int> lines = getSelectedLines(richTextBox1);

    foreach (int l in lines) trimLeftLine(richTextBox1, l, tb_comment.Text);
    foreach (int l in lines) colorLine(richTextBox1, l, Color.Black);

}

Answer 3

这可能会做的工作

if (richTextBox1.SelectionLength >= 0 && richTextBox1.Text.Length > 0)
{
    int firstCharIndex = richTextBox1.GetFirstCharIndexOfCurrentLine();
    if (richTextBox1.SelectionLength == 0)
    {
        int lineNumber = richTextBox1.GetLineFromCharIndex(firstCharIndex);
        int lastCharIndex = richTextBox1.GetFirstCharIndexFromLine(lineNumber + 1);
        if (lastCharIndex == -1) lastCharIndex = richTextBox1.Text.Length;
        richTextBox1.Select(firstCharIndex, lastCharIndex - firstCharIndex);
        richTextBox1.SelectionColor = Color.Red;
        richTextBox1.SelectedText = "//" + richTextBox1.SelectedText;
        richTextBox1.Select(firstCharIndex--, lastCharIndex - firstCharIndex);
        richTextBox1.Focus();
    }
    else
    {
        int selStart = richTextBox1.SelectionStart;
        int selLen = richTextBox1.SelectionLength;
        richTextBox1.SelectionStart = selStart + selLen;
        int lastLineFirstChar = richTextBox1.GetFirstCharIndexOfCurrentLine();
        int lastLineNumber = richTextBox1.GetLineFromCharIndex(lastLineFirstChar);
        int lastLineLastChar = richTextBox1.GetFirstCharIndexFromLine(lastLineNumber + 1);
        if (lastLineLastChar == -1) lastLineLastChar = richTextBox1.Text.Length;

        string beforeSelection = richTextBox1.Text.Substring(0, firstCharIndex);
        string afterSelection = richTextBox1.Text.Substring(lastLineLastChar, richTextBox1.Text.Length - lastLineLastChar);
        string selectionText = richTextBox1.Text.Substring(firstCharIndex, lastLineLastChar - firstCharIndex);

        string[] lines = selectionText.Split(new string[] { Environment.NewLine, "\r", "\n", "\r\n" }, StringSplitOptions.RemoveEmptyEntries);
        string commentedText = "";
        for (int i = 0; i < lines.Length; i++) commentedText += "//" + lines[i] + "\r\n";

        richTextBox1.Text = beforeSelection + afterSelection;
        richTextBox1.SelectionStart = firstCharIndex;
        richTextBox1.SelectedText = commentedText;
        richTextBox1.Select(firstCharIndex, lastLineLastChar - firstCharIndex + (lines.Length * 2));
        richTextBox1.SelectionColor = Color.Red;
        richTextBox1.Focus();
    }
}