在C#中快速实现拖放操作

文章出处：http://www.gispower.org/article/dev/2008/1030/081030112125ADC77IGB7A4EI0847H71.html

拖放操作是一个我比较喜欢的用户体验，但实现起来稍显麻烦，这里我将它的常用方式简单的集合了一下，作为扩展方法，以便快速调用：

static class DrapDropExtend
{
    public static void SimpleDrapDrop<T>(this Control c, string dataformat, Action<T> hanlder) where T : class
    {
        c.AllowDrop = true;
        c.DragEnter += (s, e) =>
            {
                if (e.Data.GetDataPresent(dataformat))
                    e.Effect = DragDropEffects.Copy;
                else
                    e.Effect = DragDropEffects.None;
            };

        c.DragDrop += (s, e) =>
            {
                var data = e.Data.GetData(dataformat) as T;
                hanlder(data);
            };
    }

    public static void SimpleDrapDrop(this Control c, Action<DragEventArgs> enterHanlder, Action<DragEventArgs> dropHanlder)
    {
        c.AllowDrop = true;
        c.DragEnter += (s, e) => enterHanlder(e);
        c.DragDrop += (s, e) => enterHanlder(e);
    }

    public static void SimpleDrapDrop(this Control c, DragEventHandler enterHanlder, DragEventHandler dropHanlder)
    {
        c.AllowDrop = true;
        c.DragEnter += enterHanlder;
        c.DragDrop += dropHanlder;
    }
}

该类使得实现拖放更加简单了，一个简单的示例如下：

public Form1()
{
    InitializeComponent();
    this.SimpleDrapDrop<string>(DataFormats.Text, x => this.Text = x);
}

这比通过IDE来实现要简洁得多。