如何返回IAsyncOperation <TReturn>结果？

Question

我想异步执行CPU密集型工作。我想使用这样的代码：

   ....
   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 ?????;
    }

我应该如何写以上return声明？

Answer 1

IAsyncOperation<TResult>如果要编写WinRT组件，则必须返回。但是，我建议将IAsyncOperation<TResult>代码编写为更自然的async/ await实现的简单包装。

有一个专门为这种情况编写的扩展方法：

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;
}

Answer 2

您可以使用异步/等待模式并返回Task<>对象：

...
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;
}