文件丢失到Windows窗体的文件扩展名 [英] Get File Extension of File Dropped Onto Windows Form

问题描述

如何捕获丢失到Windows窗体上的文件的文件扩展名？例如（下面的伪代码）

How can I capture the file extension of the file dropped onto a windows form? For example (pseudocode below)

if extension = .xlsx { method1 }
if extension = .txt { method2 }
else { MessageBox.Show("Please drag/drop either a .xlsx or a .txt file"); }

推荐答案

你必须记住，用户可以比单个文件拖动更多。使用此代码作为起点。首先要做的是修改DragEnter事件处理程序，以便用户根本无法丢弃错误的文件类型：

You have to keep in mind that the user can drag more than a single file. Use this code as a starting point. First thing you want to do is modify the DragEnter event handler so the user simply can't drop the wrong kind of file at all:

    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 = System.IO.Path.GetExtension(file);
            if (ext.Equals(".xlsx", StringComparison.CurrentCultureIgnoreCase) ||
                ext.Equals(".txt",  StringComparison.CurrentCultureIgnoreCase)) {
                e.Effect = DragDropEffects.Copy;
                return;
            }
        }
    }

DragDrop事件处理程序很多同样的，而不是分配e.Effect你处理文件，无论你想要做什么。

The DragDrop event handler is much the same, instead of assigning e.Effect you process the file, whatever you want to do with it.

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