将按钮放在字符串前面

Question

如何将button放置在设置标记的行的前面？ button应放置在字符串之前。如果用户移动标记，那么button将移动到另一个字符串。如图所示。

此刻，button显示在click发生的行的对面。

 private void richTextBox1_MouseClick(object sender, MouseEventArgs e) 
    { 
     buttonaddmenu.Visible = true; 

     int index = richTextBox1.SelectionStart; 
     int line = richTextBox1.GetLineFromCharIndex(index); 
     buttonaddmenu.Visible = true; 
     int x = richTextBox1.Location.X - 10; 
     int y = 25; 

     for (int i = 0; i < richTextBox1.Lines.Length; i++) 
     { 
      buttonaddmenu.Location = new Point(3, Cursor.Position.Y - 170); 
     } 
    } 

Answer 1

您可以通过增加或减少的X和Y改变基于按钮的大小（我的按钮大小的21，23）的新位置（例如：locationOnForm.X-20）试试这个：

 private void richTextBox1_SelectionChanged(object sender, EventArgs e) 
     { 
     var pos = richTextBox1.GetPositionFromCharIndex(richTextBox1.SelectionStart); 
     Point locationOnForm = richTextBox1.FindForm().PointToClient(richTextBox1.Parent.PointToScreen(richTextBox1.Location)); 
     Point newLocation = new Point(locationOnForm.X-20, 
          pos.Y + locationOnForm.Y); 
     button2.Location = newLocation; 
     } 

更新

 Point locationOnForm = panel1.FindForm().PointToClient(panel1.Parent.PointToScreen(richTextBox1.Location));