UWP 应用:FileOpenPicker PickSingleFileAsync() 不能等待 [英] UWP app: FileOpenPicker PickSingleFileAsync() can't await

问题描述

我试图让用户使用 FileOpenPicker 类浏览文件，但是当我将 PickSingleFileAsync 函数与 await 一起使用时，出现以下错误:

I'm trying to let the user browse for a file with the FileOpenPicker class, but when I use the PickSingleFileAsync function with await, I get following error:

IAsyncOperation"不包含GetAwaiter"的定义，并且找不到接受IAsyncOperation"类型的第一个参数的扩展方法GetAwaiter"(您是否缺少System"的 using 指令?)

'IAsyncOperation' does not contain a definition for 'GetAwaiter' and no extension method 'GetAwaiter' accepting a first argument of type 'IAsyncOperation' could be found (are you missing a using directive for 'System'?)

这是在最后一行给出错误的函数:

This is the function that gives the error on it's last line:

private async void browseFileButton_Click(object sender, RoutedEventArgs e) {
    FileOpenPicker filePicker = new FileOpenPicker();
    filePicker.ViewMode = PickerViewMode.Thumbnail;

    selectedFile = await filePicker.PickSingleFileAsync();
}

来自 Microsoft 的文档包含一个以相同方式使用 FileOpenPicker 的示例.有没有人遇到过这个问题，或者有没有人解决这个问题?

The documentation from Microsoft contains an example that uses the FileOpenPicker in the same way. Has anybody had this problem or has anybody a solution for this problem?

推荐答案

你有吗:

使用系统；

在类文件的顶部?我只是尝试将您的示例添加到项目中，并在删除此引用时重复了您的错误...

at the top of the class file? I just tried adding your sample to a project and duplicated your error when I removed this reference...

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