C# 控件 RichTextBox 顯示行號，並且與Panel相互聯動

我們在使用到WINFORM窗體工作中，要求RichTextBox 加入行號；

之前有看到大牛們寫的，但是太復雜繁多，而且有用雙TextBox進行聯動，非常不錯，今天我們嘗試RichTextBox +Panel相互聯動如下效果.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

左側灰色為Panel，右側為RichTextBox 控件

 

1：准備Panel畫布如下代碼，當接到文件字符后進行坐標解析，繪制行號。

private void showLineNo()
        {
            //獲得當前坐標信息
            Point p = this.txtFileView.Location;
            int crntFirstIndex = this.txtFileView.GetCharIndexFromPosition(p);

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

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

            p.Y += this.txtFileView.Height;

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

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

            //准備畫圖
            Graphics g = this.panel2.CreateGraphics();

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

            SolidBrush brush = new SolidBrush(Color.Green);

            //畫圖開始

            //刷新畫布

            Rectangle rect = this.panel2.ClientRectangle;
            brush.Color = this.panel2.BackColor;

            g.FillRectangle(brush, 0, 0, this.panel2.ClientRectangle.Width, this.panel2.ClientRectangle.Height);

            brush.Color = Color.White;//重置畫筆顏色

            //繪制行號

            int lineSpace = 0;

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

            }

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

            }
            int brushX = this.panel2.ClientRectangle.Width - Convert.ToInt32(font.Size * 3);

            int brushY = crntLastPos.Y + Convert.ToInt32(font.Size * 0.21f);
            for (int i = crntLastLine; i >= crntFirstLine; i--)
            {

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

                brushY -= lineSpace;
            }

            g.Dispose();

            font.Dispose();

            brush.Dispose();
        }

 

2：事件准備（啟用）如下事件

控件加載事件

private void txtFileView_TextChanged(object sender, EventArgs e)
        {
            showLineNo();
        }

控件滾動事件（當算出的行數大於本控件長度）

private void txtFileView_VScroll(object sender, EventArgs e)
        {
            showLineNo();
        }

完成后，直接啟用運行，Demo事例中的效果就出來，方便大家用於各種應用上.