private void Form1_DragEnter(object sender, System.Windows.Forms.DragEventArgs e)
{
if (e.Data.GetDataPresent(DataFormats.FileDrop))
e.Effect = DragDropEffects.Link;
else e.Effect = DragDropEffects.None;
}

private void Form1_DragDrop(object sender, System.Windows.Forms.DragEventArgs e)
{
//其中label1.Text显示的就是拖进文件的文件名；
label1.Text = ((System.Array)e.Data.GetData(DataFormats.FileDrop)).GetValue(0).ToString();
}