Question

使用相同的Load Operation来加载多个实体然后异步地将它绑定到单个事件处理程序是否是可接受的做法？我这样做是因为我使用的是繁忙的指标，而我们并不知道哪个实体会更快地返回。

或者我应该将负载分成多个Load Operation / EventHandler对吗？

  LoadOperation GetResult;

    private void LoadinDatagrid()
    {   
        IsBusy = true;
        GetResult = DomainContext.Current.Load(GetSomething1Query());
        GetResult = DomainContext.Current.Load(GetSomething2Query());
        GetResult = DomainContext.Current.Load(GetSomething3Query());         

        GetResult.Completed += new EventHandler(GetResult_Completed);                     
    }

    void GetResult_Completed(object sender, EventArgs e)
    {

        GetSomething1 = DomainContext.Current.Something1;
        GetSomething2 = DomainContext.Current.Something2;
        GetSomething3 = DomainContext.Current.Something3;
        GetResult.Completed -= new EventHandler(GetResult_Completed);
        IsBusy = false;     
    }

Answer 1

LoadOperation GetResult;

private void LoadinDatagrid()
{   
    IsBusy = true;

    GetResult.Completed += new EventHandler(GetResult_Completed);       
    GetResult = DomainContext.Current.Load(GetSomething1Query());
    GetResult = DomainContext.Current.Load(GetSomething2Query());
    GetResult = DomainContext.Current.Load(GetSomething3Query());         

}

void GetResult_Completed(object sender, EventArgs e)
{
   if(e.result!=null){
    if(e.result.x=="GetSomething1")
    GetSomething1 = DomainContext.Current.Something1;
    else if(e.result.x=="GetSomething2")
    GetSomething2 = DomainContext.Current.Something2;
    else if(e.result.x=="GetSomething3")
    GetSomething3 = DomainContext.Current.Something3;
    //
    //Because when returned 1st data then stop eventhandler.
    //GetResult.Completed -= new EventHandler(GetResult_Completed);
    //
   }
    IsBusy = false;     
}

Answer 2

尝试以下方法：

private int loadCounter;

private void LoadinDatagrid()
{   
    loadCounter = 3;
    IsBusy = true;
    GetResult = DomainContext.Current.Load(GetSomething1Query(), LoadCompleted);
    GetResult = DomainContext.Current.Load(GetSomething2Query(), LoadCompleted);
    GetResult = DomainContext.Current.Load(GetSomething3Query(), LoadCompleted);         
}

private void LoadCompleted(LoadOperation result)
{
    Interlocked.Decrement(loadCounter); // Thread save decrementing
    if(loadCounter == 0) // All queries have been loaded
    {
        IsBusy = false;
    }
}

Silverlight 4 + RIA服务负载

2 个答案: