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Hello world!

Welcome to TuanZi. This is my first post.

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Configuring Xcode to use Subversion

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Whether you are a new Apple developer or an experienced Cocoa engineer with roots in NeXTStep, you will understand the need to back up your hard work. Integrating Xcode with subversion not only allows you to back up your code, but it also enables you to keep a history of changes that you can revert back to or compare your code against. This is called version control. This article assumes that you already have your own subversion repository that you have read and write access to. If you want to setup a subversion server of your own, I suggest consulting the almighty google for a wide range of articles on how to accomplish this task. Read on for screenshots, details and lots of fun.

Step 1) Tell Xcode about your repository.

Xcode has the ability to communicate with subversion using native svn communication, ssh+svn, http and https. The most popular of the various methods is https which allows you to save your data over an encrypted channel. Because after all, it is important that your trade secrets are never exposed to your competitor! To add a subversion repository, navigate to the “SCM” menu and select the “Configure SCM Repositories…” option. Fill in the relevant information which should be readily available to you, if it’s not, contact the person who administrates your SVN repository for more details.
Connecting to the Repository Using svnserve

Step 2) Let’s put your code on the Subversion server

Go back to the SCM menu and select the “Repositories” menu item. From this screen you can now “import” your hard work into the repository. Click the “Import” button and navigate to your Xcode project’s directory. If you haven’t done so already, you might want to think about configuring your project to use a directory for builds that lives OUTSIDE of your Xcode project directory. If you configure your build paths (in your Project Settings) in this manner you will avoid checking in binary copies of your application, which is typically unnecessary as subversion is source control management (SCM) not binary control management. After you have settled on your build path situation, go ahead and select your entire Xcode project and import it. If the subversion server is “local” to your computer this process will be lighting fast. If not, wait a while for it to finish.
Importing a Project to the Repository

Step 3) Check-out your newly imported code from the repository

Now that you have stored your source code on the subversion server, the current local copy of your Xcode project can be moved off to the side, or even better, deleted. Don’t worry since you placed the files inside of the repository, we can quickly check them out so that your working copy will be attached to the repository. Navigate back to the SCM menu (noticing a trend here?) and select “Repositories”. From the repository browsing window select your Xcode project and click the “Checkout” button. Xcode will ask you for a place to save the project. Any location will do, just save it.Checking Out the Project

Step 4) Inform your Project that it is under SCM control

Time to tell Xcode that your project is being managed by SCM, or more specifically subversion. Pull your Project Settings and click the “Project Roots & SCM” button. It will bring up the window you see below where you want to select and then click the small black arrows until it reads your subversion repository. That it. Hit Ok and return to Xcode. Your project is now Subversion aware.tellxcodeitsmanaged

The Final Steps
The hard work has paid off. You can now right click the menu bar of the navigation sidebar and check the “SCM” entry. This will place an additional column in the sidebar which will have an “M” in it if a file is “newer” (meaning it needs to be committed) than what is in the Subversion repository. You can now right click a file and commit it to the repository. When you do that, Xcode will ask you to enter a comment that describes what changes were made to the file.

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C#异步调用四大方法详解

C#异步调用四大方法是什么呢?C#异步调用四大方法的使用是如何进行的呢?让我们首先了解下什么时候用到C#异步调用:

.NET Framework 允许您C#异步调用任何方法。定义与您需要调用的方法具有相同签名的委托;公共语言运行库将自动为该委托定义具有适当签名的 BeginInvoke 和 EndInvoke 方法。

BeginInvoke 方法用于启动C#异步调用。它与您需要异步执行的方法具有相同的参数,只不过还有两个额外的参数(将在稍后描述)。BeginInvoke 立即返回,不等待C#异步调用完成。BeginInvoke 返回 IasyncResult,可用于监视调用进度。

EndInvoke 方法用于检索C#异步调用结果。调用 BeginInvoke 后可随时调用 EndInvoke 方法;如果C#异步调用未完成,EndInvoke 将一直阻塞到C#异步调用完成。EndInvoke 的参数包括您需要异步执行的方法的 out 和 ref 参数(在 Visual Basic 中为 ByRef 和 ByRef)以及由 BeginInvoke 返回的 IAsyncResult。

注意 Visual Studio .NET 中的智能感知功能会显示 BeginInvoke 和 EndInvoke 的参数。如果您没有使用 Visual Studio 或类似的工具,或者您使用的是 C# 和 Visual Studio .NET,请参见异步方法签名获取有关运行库为这些方法定义的参数的描述。

本主题中的代码演示了四种使用 BeginInvoke 和 EndInvoke 进行C#异步调用的常用方法。调用了 BeginInvoke 后,可以:

· 进行某些操作,然后调用 EndInvoke 一直阻塞到调用完成。

· 使用 IAsyncResult.AsyncWaitHandle 获取 WaitHandle,使用它的 WaitOne 方法将执行一直阻塞到发出 WaitHandle 信号,然后调用 EndInvoke。

· 轮询由 BeginInvoke 返回的 IAsyncResult,确定C#异步调用何时完成,然后调用 EndInvoke。

· 将用于回调方法的委托传递给 BeginInvoke。该方法在C#异步调用完成后在 ThreadPool 线程上执行,它可以调用 EndInvoke。

警告:始终在C#异步调用完成后调用 EndInvoke。

测试方法和异步委托

四个示例全部使用同一个长期运行的测试方法 TestMethod。该方法显示一个表明它已开始处理的控制台信息,休眠几秒钟,然后结束。TestMethod 有一个 out 参数(在 Visual Basic 中为 ByRef),它演示了如何将这些参数添加到 BeginInvoke 和 EndInvoke 的签名中。您可以用类似的方式处理 ref 参数(在 Visual Basic 中为 ByRef)。

下面的代码示例显示 TestMethod 以及代表 TestMethod 的委托;若要使用任一示例,请将示例代码追加到这段代码中。

注意 为了简化这些示例,TestMethod 在独立于 Main() 的类中声明。或者,TestMethod 可以是包含 Main() 的同一类中的 static 方法(在 Visual Basic 中为 Shared)。

using System;
using System.Threading;

public class AsyncDemo {
// The method to be executed asynchronously.
//
public string TestMethod(
int callDuration, out int threadId) {
Console.WriteLine(“Test method begins.”);
Thread.Sleep(callDuration);
threadId = AppDomain.GetCurrentThreadId();
return “MyCallTime was ” + callDuration.ToString();
}
}

// The delegate must have the same signature as the method
// you want to call asynchronously.
public delegate string AsyncDelegate(
int callDuration, out int threadId);

using System;
using System.Threading;

public class AsyncDemo {
// The method to be executed asynchronously.
//
public string TestMethod(
int callDuration, out int threadId) {
Console.WriteLine(“Test method begins.”);
Thread.Sleep(callDuration);
threadId = AppDomain.GetCurrentThreadId();
return “MyCallTime was ” + callDuration.ToString();
}
}

// The delegate must have the same signature as the method
// you want to call asynchronously.
public delegate string AsyncDelegate(
int callDuration, out int threadId);

C#异步调用四大方法之使用 EndInvoke 等待异步调用

异步执行方法的最简单方式是以 BeginInvoke 开始,对主线程执行一些操作,然后调用 EndInvoke。EndInvoke 直到C#异步调用完成后才返回。这种技术非常适合文件或网络操作,但是由于它阻塞 EndInvoke,所以不要从用户界面的服务线程中使用它。

public class AsyncMain {
static void Main(string[] args) {
// The asynchronous method puts the thread id here.
int threadId;

// Create an instance of the test class.
AsyncDemo ad = new AsyncDemo();

// Create the delegate.
AsyncDelegate dlgt = new AsyncDelegate(ad.TestMethod);

// Initiate the asychronous call.
IAsyncResult ar = dlgt.BeginInvoke(3000,
out threadId, null, null);

Thread.Sleep(0);
Console.WriteLine(“Main thread {0} does some work.”,
AppDomain.GetCurrentThreadId());

// Call EndInvoke to Wait for
//the asynchronous call to complete,
// and to retrieve the results.
string ret = dlgt.EndInvoke(out threadId, ar);

Console.WriteLine(“The call executed on thread {0},
with return value \”{1}\”.”, threadId, ret);
}
}

C#异步调用四大方法之使用 WaitHandle 等待异步调用

等待 WaitHandle 是一项常用的线程同步技术。您可以使用由 BeginInvoke 返回的 IAsyncResult 的 AsyncWaitHandle 属性来获取 WaitHandle。C#异步调用完成时会发出 WaitHandle 信号,而您可以通过调用它的 WaitOne 等待它。

如果您使用 WaitHandle,则在C#异步调用完成之后,但在通过调用 EndInvoke 检索结果之前,可以执行其他处理。

public class AsyncMain {
static void Main(string[] args) {
// The asynchronous method puts the thread id here.
int threadId;

// Create an instance of the test class.
AsyncDemo ad = new AsyncDemo();

// Create the delegate.
AsyncDelegate dlgt = new AsyncDelegate(ad.TestMethod);

// Initiate the asychronous call.
IAsyncResult ar = dlgt.BeginInvoke(3000,
out threadId, null, null);

Thread.Sleep(0);
Console.WriteLine(“Main thread {0} does some work.”,
AppDomain.GetCurrentThreadId());

// Wait for the WaitHandle to become signaled.
ar.AsyncWaitHandle.WaitOne();

// Perform additional processing here.
// Call EndInvoke to retrieve the results.
string ret = dlgt.EndInvoke(out threadId, ar);

Console.WriteLine(“The call executed on thread {0},
with return value \”{1}\”.”, threadId, ret);
}
}

C#异步调用四大方法之轮询异步调用完成

您可以使用由 BeginInvoke 返回的 IAsyncResult 的 IsCompleted 属性来发现C#异步调用何时完成。从用户界面的服务线程中进行C#异步调用时可以执行此操作。轮询完成允许用户界面线程继续处理用户输入。

public class AsyncMain {
static void Main(string[] args) {
// The asynchronous method puts the thread id here.
int threadId;

// Create an instance of the test class.
AsyncDemo ad = new AsyncDemo();

// Create the delegate.
AsyncDelegate dlgt = new AsyncDelegate(ad.TestMethod);

// Initiate the asychronous call.
IAsyncResult ar = dlgt.BeginInvoke(3000,
out threadId, null, null);

// Poll while simulating work.
while(ar.IsCompleted == false) {
Thread.Sleep(10);
}

// Call EndInvoke to retrieve the results.
string ret = dlgt.EndInvoke(out threadId, ar);

Console.WriteLine(“The call executed on thread {0},
with return value \”{1}\”.”, threadId, ret);
}
}

C#异步调用四大方法之异步调用完成时执行回调方法

如果启动异步调用的线程不需要处理调用结果,则可以在调用完成时执行回调方法。回调方法在 ThreadPool 线程上执行。

要使用回调方法,必须将代表该方法的 AsyncCallback 委托传递给 BeginInvoke。也可以传递包含回调方法将要使用的信息的对象。例如,可以传递启动调用时曾使用的委托,以便回调方法能够调用 EndInvoke。

public class AsyncMain {
// Asynchronous method puts the thread id here.
private static int threadId;

static void Main(string[] args) {
// Create an instance of the test class.
AsyncDemo ad = new AsyncDemo();

// Create the delegate.
AsyncDelegate dlgt = new AsyncDelegate(ad.TestMethod);

// Initiate the asychronous call. Include an AsyncCallback
// delegate representing the callback method, and the data
// needed to call EndInvoke.
IAsyncResult ar = dlgt.BeginInvoke(3000,
out threadId,
new AsyncCallback(CallbackMethod),
dlgt );

Console.WriteLine(“Press Enter to close application.”);
Console.ReadLine();
}

// Callback method must have the same signature as the
// AsyncCallback delegate.
static void CallbackMethod(IAsyncResult ar) {
// Retrieve the delegate.
AsyncDelegate dlgt = (AsyncDelegate) ar.AsyncState;

// Call EndInvoke to retrieve the results.
string ret = dlgt.EndInvoke(out threadId, ar);

Console.WriteLine(“The call executed on thread {0},
with return value \”{1}\”.”, threadId, ret);
}
}