不包含“完成” /“然后”的定义

Question

While using CreateFileAsync winRT APi i am getting this error;

' Windows.Foundation.IAsyncOperation<Windows.Storage.StorageFile> ' does not contain a definition for ' done ' and no extension method ' done ' accepting a first argument of type ' Windows.Foundation.IAsyncOperation<Windows.Storage.StorageFile> ' could be found (are you missing a using directive or an assembly reference)

Why?

The example from msdn is thesame as well msdn API reference

Answer 1

Lise I said in a comment, the example is in JavaScript, not C#. The proper way to use asynchronous methods from C# is to use await :

var file = await Windows.Storage.DownloadsFolder.CreateFileAsync("sample.txt");
// Your code

This code must be in a method marked as async .