在code本可以得到一个有点复杂，但本质上则需要捕捉到你的窗体上的MouseDown，的MouseMove，和MouseUp事件。事情是这样的：

The code for this can get a bit complex, but essentially you will need to capture the MouseDown, MouseMove, and MouseUp events on your form. Something like this:

public void Form1_MouseDown(object sender, MouseEventArgs e)
{
    if(e.Button != MouseButton.Left)
        return;

    // Might want to pad these values a bit if the line is only 1px,
    // might be hard for the user to hit directly
    if(e.Y == myControl.Top)
    {
        if(e.X >= myControl.Left && e.X <= myControl.Left + myControl.Width)
        {
            _capturingMoves = true;
            return;
        }
    }

    _capturingMoves = false;
}

public void Form1_MouseMove(object sender, MouseEventArgs e) 
{
    if(!_capturingMoves)
        return;

    // Calculate the delta's and move the line here
}

public void Form1_MouseUp(object sender, MouseEventArgs e) 
{
    if(_capturingMoves)
    {
        _capturingMoves = false;
        // Do any final placement
    }
}