在Matlab中读取和处理大型文本文件(Reading and processing a large text file in Matlab)

 你永远不会得到一个.NET应用程序立即显示的启动画面。 即使你已经使用程序集来消除JIT编译时间，你仍然需要等待所有的.NET Framework DLL被加载到内存中。 这是一个非常大的框架，并且需要花费不少的时间来加载冷启动。 没有什么可以真正做到的。 
 
 微软试图尽可能地缓解痛苦。 WindowsFormsApplicationBase类 （它在Microsoft.VisualBasic命名空间中定义，但不要让它吓跑你;它完全可以从C＃应用程序中使用）提供了一个用于显示启动画面的内置机制。 您所要做的就是将其SplashScreen属性设置为适当的形式，其他所有内容都在幕后处理。 即使在冷启动的情况下，它已经针对最大响应时间进行了大量优化，但仍不会立即发生 。 
 
 您唯一的选择是在非托管代码中编写小封装，其唯一目的是尽快抛出初始屏幕，然后调用.NET应用程序开始启动自身。 当然，这里的打火机越好越好。 C ++是一个选项，但C可能是更好的选择。 您需要最大限度地减少必须链接的外部库的数量，因此像MFC或Qt这样的框架绝对是不可用的：您需要直接定位Windows API。 
 
 Visual Studio团队在VS 2010中做了类似的事情。他们对他们的博客上提供的流程有一个非常有趣的解释： 
 
 
 
 尽管Visual Studio 2010使用WPF作为其主窗口，但使用WPF作为启动屏幕需要等待CLR和WPF初始化，然后才能在屏幕上绘制单个像素。 尽管我们在.Net 4.0中对CLR和WPF启动速度做了一些巨大的改进，但仍然不能完全匹配原始Win32的性能。 因此，我们选择了原生C ++代码和Win32作为启动画面。 
 
 
 但我不会在这里花太多时间。 由于您通常应该给用户启用和关闭启动屏幕的选项，并且大多数用户会选择关闭启动屏幕，因此很多人不太可能首先看到它。 任何好的优化分析器都会告诉你，这不值得优化。 

You're never going to get a splash screen for a .NET application to show instantly. Even if you've NGen'ed the assemblies to eliminate the JIT-compile time, you still have to wait while all of the .NET Framework DLLs are loaded into memory. It's a pretty large framework, and it takes a non-trivial amount of time to load upon a cold start. Nothing you can really do about that.
 
Microsoft has tried to ease the pain as much as possible. The WindowsFormsApplicationBase class (it's defined in the Microsoft.VisualBasic namespace, but don't let that scare you off; it's perfectly usable from a C# application) provides a built-in mechanism for showing a splash screen. All you have to do is set its SplashScreen property to the appropriate form, and everything else is handled behind the scenes. It's been heavily optimized for maximum response time, even in a cold-start situation, but it's still not going to be instant.
 
The only other option that you have is to write small wrapper in unmanaged code, whose only purpose is to throw the splash screen up as quickly as possible, then call your .NET application to start launching itself. The lighter the better here, of course. C++ is an option, but C is probably a better option. You need to minimize the number of external libraries that you have to link, so a framework like MFC or Qt is definitely out: you need to target the Windows API directly.
 
The Visual Studio team did something similar in VS 2010. They have a pretty interesting explanation of the process available on their blog:
 
 
 
Even though Visual Studio 2010 uses WPF for its main window, using WPF for the splash screen would require that we wait for the CLR and WPF to initialize before we could paint a single pixel on the screen. While we’ve made some tremendous improvements in CLR and WPF startup speed in .Net 4.0, it still can’t quite match the performance of raw Win32. So, the choice was made to stay with native C++ code and Win32 for the splash screen.
 
 
But I wouldn't spend too much time here. Since you should generally give users the option to turn splash screens on and off, and most users will opt to turn it off, it's unlikely that very many people will ever see it in the first place. Any good optimization profiler would tell you that it isn't worth optimizing.