using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Text;
using System.Windows.Forms;
using System.IO;

namespace Common
{
    public partial class UserControl1 : UserControl
    {
        public UserControl1()
        {
            InitializeComponent();
        }

        private void UserControl1_DragEnter(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.FileDrop))//表示此时为文件拖拽
                e.Effect = DragDropEffects.Copy;
        }

        private void UserControl1_DragDrop(object sender, DragEventArgs e)
        {
            string fileName = ((string[])e.Data.GetData(DataFormats.FileDrop))[0];
            try
            {
                Image image = Image.FromFile(fileName);
                this.pictureBox1.Image = image;
            }
            catch
            {
                MessageBox.Show("当前拖拽的文件不是有效的图像文件");
                return;
            }
        }
    }
}

------解决方案--------------------
事件过滤,
由这两个事件,触发U控件的事件.

------解决方案--------------------
楼主再说明白一点吧。

------解决方案--------------------

[Quote=引用:]
C# code
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Text;
using System.Windows.Forms;
using System.IO;

namespace Common
{
    public partial class UserControl1 : UserControl
    {
        public UserControl1()
        {
            InitializeComponent();
        }

        private void UserControl1_DragEnter(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.FileDrop))//表示此时为文件拖拽
                e.Effect = DragDropEffects.Copy;
        }

        private void UserControl1_DragDrop(object sender, DragEventArgs e)
        {
            string fileName = ((string[])e.Data.GetData(DataFormats.FileDrop))[0];
            try
            {
                Image image = Image.FromFile(fileName);
                this.pictureBox1.Image = image;
            }
            catch
            {
                MessageBox.Show("当前拖拽的文件不是有效的图像文件");
                return;
            }
        }
    }
}