拖放显示带线的圆圈

Question

我想我的设置是准确的，但是每当我尝试将文件拖到我的表单上时，它只会显示一个带有一条线的圆圈。哪个部分设置不正确？

private void Form1(object sender, EventArgs e)
{
  this.AllowDrop = true;
  this.DragDrop += new DragEventHandler(Form1_DragDrop);
  this.DragEnter += new DragEventHandler(Form1_DragEnter);
}
private void Form1_DragDrop(object sender, DragEventArgs e)
{
  if (!e.Data.GetDataPresent(DataFormats.FileDrop)) return;
  string[] files = (string[])e.Data.GetData(DataFormats.FileDrop);
  foreach (var file in files)
  {
    var ext = Path.GetExtension(file);
    if (ext.Equals(".xlsx", StringComparison.CurrentCultureIgnoreCase))
    {
        e.Effect = DragDropEffects.Copy;
        MessageBox.Show(sender.ToString());
        return;
    }
    else { MessageBox.Show("This filetype is not allowed");
  }
}
private void Form1_DragEnter(object sender, DragEventArgs e)
{
  if (!e.Data.GetDataPresent(DataFormats.FileDrop)) return;
  string[] files = (string[])e.Data.GetData(DataFormats.FileDrop);
  foreach (var file in files)
  {
    var ext = Path.GetExtension(file);
    if (ext.Equals(".xlsx", StringComparison.CurrentCultureIgnoreCase))
    {
        e.Effect = DragDropEffects.Copy;
        MessageBox.Show(sender.ToString());
        return;
    }
    else { MessageBox.Show("This filetype is not allowed");
  }
}

编辑代码

Answer 1

这对我有用...

public partial class Form1 : Form
{
    public Form1()
    {
        this.InitializeComponent();
        this.AllowDrop = true;
        this.DragDrop += new DragEventHandler(Form1_DragDrop);
        this.DragEnter += new DragEventHandler(Form1_DragEnter);
    }
    private void Form1_DragDrop(object sender, DragEventArgs e)
    {
        if (e.Data.GetDataPresent(DataFormats.FileDrop))
        {
            string[] files = (string[])e.Data.GetData(DataFormats.FileDrop);
            foreach (var file in files)
            {
                MessageBox.Show(file);
            }
        }
    }

    private void Form1_DragEnter(object sender, DragEventArgs e)
    {
        if (e.Data.GetDataPresent(DataFormats.FileDrop))
        {
            e.Effect = DragDropEffects.Copy;
        }
    }
}

从 windows 资源管理器/我的桌面等中删除任何文件会显示一个包含路径和文件名的消息框

拖放显示带线的圆圈

Drag & Drop Shows Circle With Line Through It

c#

drag-and-drop

winforms