Form1.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace FileDrag
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        /// <summary>
        /// 拖动到控件区域
        /// </summary>
        private void Form1_DragEnter(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.FileDrop))
            {
                e.Effect = DragDropEffects.Link;
            }
            else
            {
                e.Effect = DragDropEffects.None;
            }
        }

        /// <summary>
        /// 拖动到控件区域并松开鼠标
        /// </summary>
        private void Form1_DragDrop(object sender, DragEventArgs e)
        {
            label1.Text=
                ((System.Array)e.Data.GetData(DataFormats.FileDrop)).GetValue(0).ToString();
        }
    }
}