拖放图像

本文关键字：图像 拖放 | 更新日期: 2023-09-27 18:01:36

使用此代码，我可以将图像拖放到标签上，但现在我想将该图像从标签拖放到另一个标签上。我该怎么做呢?

namespace WindowsFormsApplication1
{
    public partial class Form2 : Form
    {
        public Form2()
        {
            InitializeComponent();
            Image img = Image.FromFile(@"D:'test'test.png");
            this.btnImage.Image = img;
            Image img1 = Image.FromFile(@"C:'Documents and Settings'SAURABH'Desktop'Green.ico");
            this.btnImage1.Image = img1;
        }
        private void button1_MouseDown(object sender, MouseEventArgs e)
        {
            Button btnPic = (Button)sender;
            btnPic.DoDragDrop(btnPic.Image, DragDropEffects.Copy);
        }
        private void button2_MouseDown(object sender, MouseEventArgs e)
        {
            Button btnPic = (Button)sender;
            btnPic.DoDragDrop(btnPic.Image, DragDropEffects.Copy);
        }
        private void button3_MouseDown(object sender, MouseEventArgs e)
        {
            Button btnPic = (Button)sender;
            btnPic.DoDragDrop(btnPic.Image, DragDropEffects.Copy);
        }
        private void label1_DragEnter(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.Bitmap))
            {
                e.Effect = DragDropEffects.Copy;
            }
            else
            {
                e.Effect = DragDropEffects.None;
            }
        }
        private void label10_DragEnter(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.Bitmap))
            {
                e.Effect = DragDropEffects.Copy;
            }
            else
            {
                e.Effect = DragDropEffects.None;
            }
        }
        private void label10_DragDrop(object sender, DragEventArgs e)
        {
            Label picbox = (Label)sender;
            //PictureBox picbox = (PictureBox)sender;
            Graphics g = picbox.CreateGraphics();
            g.DrawImage((Image)e.Data.GetData(DataFormats.Bitmap), new Point(0, 0));
        }
        private void label1_DragDrop(object sender, DragEventArgs e)
        {
            Label picbox = (Label)sender;
            //PictureBox picbox = (PictureBox)sender;
            Graphics g = picbox.CreateGraphics();
            g.DrawImage((Image)e.Data.GetData(DataFormats.Bitmap), new Point(0, 0));
        }
    }
}

拖放图像

问题是在您的Label s'拖放处理程序。你可以直接复制拖放操作的'payload'，代码如下:

private void Label_DragDrop(object sender, DragEventArgs e) {
    if (e.Data.GetDataPresent(typeof(Bitmap))) {
        ((Label)sender).Image = (Image)e.Data.GetData(DataFormats.Bitmap);
    }
}

你可能会发现这篇关于拖放的MSDN文章很有用。

我还注意到在你的代码中，MouseDown, DragEnter和DragDrop事件处理程序是相同的多个Button和Label控件。您可以通过编写每个处理程序一次，然后将多个控件的事件注册到每个处理程序来稍微重构一些东西。例如，您可以将Label1和Label10的DragDrop事件注册到我上面提供的处理程序。在设计器中或通过代码执行:

label1.DragDrop += Label_DragDrop;
label10.DragDrop += Label_DragDrop;
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