AutoScaleing RichTextBox

Question

我正在尝试使用只读RichTextBoxes来显示用户生成的文本。文本框和控件的高度应取决于内容，并限制为一定的最大值，超出此点的任何内容都将使用滚动条。

[AutoSize似乎不适用于RTB

public void Rescale()
{
    Point pt = rtbComment.GetPositionFromCharIndex(rtbComment.Text.Length);
    int height = rtbComment.GetPositionFromCharIndex(rtbComment.Text.Length).Y + (int)rtbComment.SelectionFont.GetHeight();
    if (height > 250)
        height = 250;
    this.Size = new System.Drawing.Size(616, height + 50);
    rtbComment.Size = new System.Drawing.Size(614, height);
}

这对于简短的注释或带有少量文本和许多换行符的注释绝对适用，但对于分成约4行的较长的一线代码，我从GetPositionFromCharIndex得到的要点全都是错误的-函数将其放置在向下105px处在y轴上实际上接近60时，使文本框大约是预期的两倍。

宽度在这里似乎不是问题，因为该框以我将其设置为的宽度开始，再次读取该点会产生相同的结果。

Answer 1

已解决。

我使用了TextRenderer.MeasureText方法。

由于此方法忽略了很长的行将在RichTextBox中接收一个或多个自动换行符的事实，因此我编写了一个函数，该函数可以通过换行符将文本手动拆分为任意长度的行，然后测量每行以检查实时出价会使用多少行。

这里是功能，万一有人需要它：

public int getLines(string comment)
{
    int height_ln = 0;

    string[] lines;

    //split into lines based on linebreaks
    if (comment.Contains("\n"))
    {
        lines = comment.Split('\n');
    }
    else
    {
        lines = new string[1];
        lines[0] = comment;
    }

    //check each line to see if it'll receive automatic linebreaks
    foreach(string line in lines)
    {
        int text_width = TextRenderer.MeasureText(line, rtbKommentar.Font).Width;
        double text_lines_raw = (double)text_width / 1400; //1400 is the width of my RichTextBox

        int text_lines = 0;

        if (line.Contains("\r")) //Please don't call me out on this, I'm already feeling dirty
            text_lines = (int)Math.Floor(text_lines_raw);
        else
            text_lines = (int)Math.Ceiling(text_lines_raw);
        if (text_lines == 0)
            text_lines++;

        height_ln += text_lines;
    }
    return height_ln; //this is the number of lines required, to adjust the height of the RichTextBox I need to multiply it by 15, which is the font's height.
}

Answer 2

WinForm RichtextBox公开了ContentsResized Event，当与MinimumSize Property和MaximumSize Property结合使用时，可以自动调整大小。

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        rtbComment.MinimumSize = new Size(250, 200);
        rtbComment.MaximumSize = new Size(250, 400);
        rtbComment.ScrollBars = System.Windows.Forms.RichTextBoxScrollBars.Vertical;
        rtbComment.ContentsResized += rtbComment_ContentResized;

    }

    private void rtbComment_ContentResized(object sender, ContentsResizedEventArgs e)
    {
        rtbComment.Size = e.NewRectangle.Size;
    }
}