C# 控件 RichTextBox 显示行号，并且与Panel相互联动

我们在使用到WINFORM窗体工作中，要求RichTextBox 加入行号；

之前有看到大牛们写的，但是太复杂繁多，而且有用双TextBox进行联动，非常不错，今天我们尝试RichTextBox +Panel相互联动如下效果.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

左侧灰色为Panel，右侧为RichTextBox 控件

 

1：准备Panel画布如下代码，当接到文件字符后进行坐标解析，绘制行号。

 1 private void showLineNo()
 2         {
 3             //获得当前坐标信息
 4             Point p = this.txtFileView.Location;
 5             int crntFirstIndex = this.txtFileView.GetCharIndexFromPosition(p);
 6 
 7             int crntFirstLine = this.txtFileView.GetLineFromCharIndex(crntFirstIndex);
 8 
 9             Point crntFirstPos = this.txtFileView.GetPositionFromCharIndex(crntFirstIndex);
10 
11             p.Y += this.txtFileView.Height;
12 
13             int crntLastIndex = this.txtFileView.GetCharIndexFromPosition(p);
14 
15             int crntLastLine = this.txtFileView.GetLineFromCharIndex(crntLastIndex);
16             Point crntLastPos = this.txtFileView.GetPositionFromCharIndex(crntLastIndex);
17 
18             //准备画图
19             Graphics g = this.panel2.CreateGraphics();
20 
21             Font font = new Font(this.txtFileView.Font, this.txtFileView.Font.Style);
22 
23             SolidBrush brush = new SolidBrush(Color.Green);
24 
25             //画图开始
26 
27             //刷新画布
28 
29             Rectangle rect = this.panel2.ClientRectangle;
30             brush.Color = this.panel2.BackColor;
31 
32             g.FillRectangle(brush, 0, 0, this.panel2.ClientRectangle.Width, this.panel2.ClientRectangle.Height);
33 
34             brush.Color = Color.White;//重置画笔颜色
35 
36             //绘制行号
37 
38             int lineSpace = 0;
39 
40             if (crntFirstLine != crntLastLine)
41             {
42                 lineSpace = (crntLastPos.Y - crntFirstPos.Y) / (crntLastLine - crntFirstLine);
43 
44             }
45 
46             else
47             {
48                 lineSpace = Convert.ToInt32(this.txtFileView.Font.Size);
49 
50             }
51             int brushX = this.panel2.ClientRectangle.Width - Convert.ToInt32(font.Size * 3);
52 
53             int brushY = crntLastPos.Y + Convert.ToInt32(font.Size * 0.21f);
54             for (int i = crntLastLine; i >= crntFirstLine; i--)
55             {
56 
57                 g.DrawString((i + 1).ToString(), font, brush, brushX, brushY);
58 
59                 brushY -= lineSpace;
60             }
61 
62             g.Dispose();
63 
64             font.Dispose();
65 
66             brush.Dispose();
67         }

View Code

 

2：事件准备（启用）如下事件

控件加载事件

1 private void txtFileView_TextChanged(object sender, EventArgs e)
2         {
3             showLineNo();
4         }

View Code

控件滚动事件（当算出的行数大于本控件长度）

1 private void txtFileView_VScroll(object sender, EventArgs e)
2         {
3             showLineNo();
4         }

View Code

完成后，直接启用运行，Demo事例中的效果就出来，方便大家用于各种应用上.