如何返回IAsyncOperation <TReturn>结果？

Question

我想异步执行CPU密集型工作。我认为使用这样的代码之一：

.... 
    updateGUIObj = await setSelectedGUICellValueAsync(arg1, arg2, cssId, isInitializeCbxChecked); 
    .... 


    public IAsyncOperation<UpdateGUIObj> setSelectedGUICellValueAsync(int arg1, int arg2, String cssId, bool isInitializeCbxChecked) 
    { 
     updateGUIObj = new UpdateGUIObj(); 

     .... // compute intensive work setting "updateGUIObj" 

     return ?????; 
    } 

我应该怎么写上面return声明？

Answer 1

您可以使用异步/等待模式，并返回Task<>对象，而不是：如果你正在写一个WinRT的组件

... 
var updateGUIObj = await setSelectedGUICellValueAsync(arg1, arg2, cssId, isInitializeCbxChecked); 
... 

public async Task<UpdateGUIObj> setSelectedGUICellValueAsync(int arg1, int arg2, String cssId, bool isInitializeCbxChecked) 
{ 
    var updateGUIObj = new UpdateGUIObj(); 

    // .... compute intensive work setting "updateGUIObj" 

    return updateGUIObj; 
} 

Answer 2

返回IAsyncOperation<TResult>是必要的。不过，我建议将IAsyncOperation<TResult>代码编写成更简单的包装，以实现更自然的async/await实现。

有这是为这种情况专门编写的extension method：

public IAsyncOperation<UpdateGUIObj> setSelectedGUICellValueAsync(int arg1, int arg2, String cssId, bool isInitializeCbxChecked) 
{ 
    return SetSelectedGuiCellValueAsync(arg1, arg2, cssId, isInitializeCbxChecked).AsAsyncOperation(); 
} 

private async Task<UpdateGUIObj> SetSelectedGuiCellValueAsync(int arg1, int arg2, String cssId, bool isInitializeCbxChecked) 
{ 
    updateGUIObj = new UpdateGUIObj(); 
    await Task.Run(....); 
    return updateGUIObj; 
}