问题委托语法在C＃ [英] Problem with delegate Syntax in C#

问题描述

我建了一个TESTBOX了解一些有关Windows应用程序的形式线程。
的Silverlight和Java所提供的调度，更新
GUI元素时，这确实有助于

I built a Testbox to learn something about threading in windows form applications. Silverlight and Java are providing the Dispatcher, which really helps when updating GUI Elements.

代码示例：
宣言类代表

Code Samples: Declaration Class Delegate

public delegate void d_SingleString(string newText);

创建线程

Create Thread

        _thread_active = true;
        Thread myThread = new Thread(delegate() { BackGroundThread(); });
        myThread.Start();

主题功能

    private void BackGroundThread()
    {
        while (_thread_active)
        {
            MyCounter++;
            UpdateTestBox(MyCounter.ToString());
            Thread.Sleep(1000);
        }
    }

委派文本框更新

Delegating TextBox Updates

    public void UpdateTestBox(string newText)
    {
        if (InvokeRequired)
        {
            BeginInvoke(new d_SingleString(UpdateTestBox), new object[] { newText });
            return;
        }
        tb_output.Text = newText;
    }

有没有申报啦免费统计IN的BeginInvoke方法宣言的方式？ ！

Is there a way to declare the Declaration of the Delate IN the BeginInvoke Method?!

像

BeginInvoke(*DELEGATE DECLARATION HERE*, new object[] { newText });

非常感谢，
rAyt

Many thanks, rAyt

推荐答案

在许多情况下，像这样的，最简单的方法是使用一种捕捉变量到线程之间传递状态;这意味着你可以保持局部的逻辑：

In many cases like this, the simplest approach is to use a "captured variable" to pass state between the threads; this means you can keep the logic localised:

public void UpdateTestBox(string newText)
{
    BeginInvoke((MethodInvoker) delegate {
        tb_output.Text = newText;
    });        
}

如果我们的期望的它的上面是特别有用工作线程上被调用（这么少点检查 InvokeRequired ） - 注意，这是无论从UI或工作线程安全的，并允许我们通过尽可能多或尽可能线程之间小的状态。

The above is particularly useful if we expect it to be called on the worker thread (so little point checking InvokeRequired) - note that this is safe from either the UI or worker thread, and allows us to pass as much or as little state between the threads.

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