调度语法的BeginInvoke [英] Dispatcher BeginInvoke Syntax

问题描述

我一直在试图遵循一些WCF数据服务的实例并具有以下代码：

I have been trying to follow some WCF Data Services examples and have the following code:

private void OnSaveCompleted(IAsyncResult result)
    {
        Dispatcher.BeginInvoke(() =>
        {
            context.EndSaveChanges(result);
        });
    }

其中由下面称为：

Which is called by the following:

this.context.BeginSaveChanges(SaveChangesOptions.Batch, this.OnSaveCompleted, null);

现在我开始有点困惑在这里。首先，代码的第一位是显示的语法错误参数类型lambda表达式是不能分配给参数类型System.Delegate。因此，而不是一味地试图按照示例代码我试图了解发生了什么怎么回事。不幸的是我奋力理解的错误加上什么是真正发生的事情。

Now I am getting a little confused here. Firstly, the first bit of code is showing a syntax error of "Argument type lambda expression is not assignable to parameter type System.Delegate". So instead of blindly trying to follow the example code I tried to understand what was going on here. Unfortunately I am struggling to understand the error plus what is actually happening.

我觉得有点愚蠢，因为我相信这是容易的。

I feel a bit stupid as I am sure this is easy.

在提前任何启迪！

推荐答案

问题是，编译器不知道什么感谢一种委托你想lambda表达式转换为。您可以修复，要么用投，或者一个独立的变量：

The problem is that the compiler doesn't know what kind of delegate you're trying to convert the lambda expression to. You can fix that either with a cast, or a separate variable:

private void OnSaveCompleted(IAsyncResult result)
{        
    Dispatcher.BeginInvoke((Action) (() =>
    {
        context.EndSaveChanges(result);
    }));
}

或

private void OnSaveCompleted(IAsyncResult result)
{
    Action action = () =>
    {
        context.EndSaveChanges(result);
    };
    Dispatcher.BeginInvoke(action);
}

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