c# 实现richTextBox带行号 问题严重 请求帮助
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();}