winform中文本框添加拖拽功能

对一个文本框添加拖拽功能：

 private void txtFolder_DragEnter(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.FileDrop))
            {
                e.Effect = DragDropEffects.Link;
                this.txtFolder.Cursor = System.Windows.Forms.Cursors.Arrow;//指定鼠标形状   
            }
            else
            {
                e.Effect = DragDropEffects.None;
            }
        }

        private void txtFolder_DragDrop(object sender, DragEventArgs e)
        {
            //DataFormats 数据的格式，下有多个静态属性都为string型，除FileDrop格式外还有Bitmap,Text,WaveAudio等格式    
            string path = ((System.Array)e.Data.GetData(DataFormats.FileDrop)).GetValue(0).ToString();
            this.txtFolder.Text = path;
            this.txtFolder.Cursor = System.Windows.Forms.Cursors.IBeam; //还原鼠标形状 
        }