c#写带行号的richTextBox

这个功能要添加两个控件：Panel/RichTextBox

 

//方法

private void showLineNo()

{

//获得当前坐标信息

Point p = this.richTextBox1.Location;
int crntFirstIndex = this.richTextBox1.GetCharIndexFromPosition(p);

int crntFirstLine = this.richTextBox1.GetLineFromCharIndex(crntFirstIndex);

Point crntFirstPos = this.richTextBox1.GetPositionFromCharIndex(crntFirstIndex);

//
p.Y += this.richTextBox1.Height;

//

     int crntLastIndex = this.richTextBox1.GetCharIndexFromPosition(p);

     int crntLastLine = this.richTextBox1.GetLineFromCharIndex(crntLastIndex);
     Point crntLastPos = this.richTextBox1.GetPositionFromCharIndex(crntLastIndex);

     //

     //

     //准备画图
     Graphics g = this.panel1.CreateGraphics();

     Font font = new Font(this.richTextBox1.Font,this.richTextBox1.Font.Style);

     SolidBrush brush = new SolidBrush(Color.Green);

     //
     //

     //画图开始

     //刷新画布

     Rectangle rect = this.panel1.ClientRectangle;
     brush.Color = this.panel1.BackColor;

g.FillRectangle(brush, 0, 0, this.panel1.ClientRectangle.Width,this.panel1.ClientRectangle.Height);

     brush.Color = Color.Green;//重置画笔颜色

     //
     //绘制行号

     int lineSpace = 0;

     if (crntFirstLine != crntLastLine)

     {
          lineSpace = (crntLastPos.Y - crntFirstPos.Y) / (crntLastLine - crntFirstLine);

     }

     else

     {
          lineSpace = Convert.ToInt32(this.richTextBox1.Font.Size);

     }

     int brushX = this.panel1.ClientRectangle.Width - Convert.ToInt32(font.Size * 3);

     int brushY = crntLastPos.Y+ Convert.ToInt32(font.Size*0.21f);//惊人的算法啊！！
     for (int i = crntLastLine; i >= crntFirstLine;i-- )

     {

           g.DrawString((i + 1).ToString(), font, brush, brushX, brushY);

           brushY -= lineSpace;
     }

     g.Dispose();

     font.Dispose();

     brush.Dispose();
}

 以上方法为绘制行号的方法，将其放在panel的paint方法中