c# - 通过拖放移动

Question

我正在尝试PictureBox使用拖放来移动 a。使用我的代码，PictureBox克隆了。但我需要能够移动它。我怎样才能做到这一点？

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        this.AllowDrop = true;
        this.pictureBox1.MouseDown += pictureBox1_MouseDown;
    }
    private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
    {
        if (e.Button == MouseButtons.Left)
        {
            var dragImage = (Bitmap)pictureBox1.Image;
            IntPtr icon = dragImage.GetHicon();
            Cursor.Current = new Cursor(icon);
            DoDragDrop(pictureBox1.Image, DragDropEffects.Copy);
            DestroyIcon(icon);
        }
    }
    protected override void OnGiveFeedback(GiveFeedbackEventArgs e)
    {
        e.UseDefaultCursors = false;
    }
    protected override void OnDragEnter(DragEventArgs e)
    {
        if (e.Data.GetDataPresent(typeof(Bitmap))) e.Effect = DragDropEffects.Copy;
    }
    protected override void OnDragDrop(DragEventArgs e)
    {
        var bmp = (Bitmap)e.Data.GetData(typeof(Bitmap));
        var pb = new PictureBox();
        pb.Image = (Bitmap)e.Data.GetData(typeof(Bitmap));
        pb.Size = pictureBox1.Size;
        pb.Location = this.PointToClient(new Point(e.X - pb.Width / 2, e.Y - pb.Height / 2));
        this.Controls.Add(pb);
    }

    [System.Runtime.InteropServices.DllImport("user32.dll")]
    extern static bool DestroyIcon(IntPtr handle);
}

Answer 1

无需创建新的 PictureBox，只需将旧的位置更新为放置位置。也就是说，而不是：

protected override void OnDragDrop(DragEventArgs e)
{
    var bmp = (Bitmap)e.Data.GetData(typeof(Bitmap));
    var pb = new PictureBox();
    pb.Image = (Bitmap)e.Data.GetData(typeof(Bitmap));
    pb.Size = pictureBox1.Size;
    pb.Location = this.PointToClient(new Point(e.X - pb.Width / 2, e.Y - pb.Height / 2));
    this.Controls.Add(pb);
}

就用这个：

protected override void OnDragDrop(DragEventArgs e)
{
    pictureBox1.Location = this.PointToClient(new Point(e.X - pictureBox1.Width / 2, e.Y - pictureBox1.Height / 2));
}

Answer 2

这是一个扩展方法，它将为任何 WinForms 控件执行此操作：http: //www.codeproject.com/Tips/178587/Draggable-WinForms-Controls? display=Print