如何检测鼠标滚轮方向(向前或向后)

Question

我需要知道如何在MouseWheel事件上确定滚动是向前还是向后(不是垂直或水平).

panel1.MouseWheel += ZoomIn

public void ZoomIn(object sender, EventArgs e)
{
     // Need to know whether the wheel is scrolled forwards or backwards
}

Answer 1

而不是EventArgs使用MouseEventArgs暴露Delta财产.向下滚动为负,向上滚动为正.

panel1.MouseWheel += ZoomIn;

public void ZoomIn(object sender, MouseEventArgs e)
{
    if(e.Delta > 0)
    {
        // The user scrolled up.
    }
    else
    {
        // The user scrolled down.
    }
}