Useful Performance Tips for C#

Useful Performance Tips for C#

 

 

The following content are fully copied from Rob's blog. Thanks, Rob.

Source URL: http://robkennedy.com/articles/146.aspx

 

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The following tips for C# are pretty useful to keep in mind while programming for future projects.

 

1. Use finally in your try {} catch {} statements to ensure resource deallocation.

2. Treat threads as a shared resource and use the optimized .NET thread pool when possible.

3. Use the server garbage collector for server based multi-CPU environments.

4. Avoid string concatenation with +=

5. Use the using(obj) short hand to simplify coding. using() is the same as try{}finally{obj.Dispose(); } and insures that obj is disposed of after use.

6. Use thread pool when using threads.

WaitCallback methTarget = new WaitCallback(myClass.Method);

ThreadPool.QueueUserWorkItem(methTarget);

 

7. Use StringBuilder for string concatenation; avoid using + to concatenate strings

8. If interacting with collections from multiple threads, you must make the collection thread safe.

 

ArrayList myAr = new ArrayList();

// Creates a synchronized wrapper around the ArrayList.

ArrayList mySyncedAr = ArrayList.Synchronized(myAr);

 

// To use collection from thread:

ArrayList myCollection = new ArrayList();

lock(myCollection.SyncRoot);

foreach ( Object item in myCollection )

{ // do work here }

 

Please note the following remarks from MSDN:

To guarantee the thread safety of the ArrayList, all operations must be done through this synchronized wrapper.

 

Enumerating through a collection is intrinsically not a thread-safe procedure. Even when a collection is synchronized, other threads could still modify the collection, which causes the enumerator to throw an exception. To guarantee thread safety during enumeration, you can either lock the collection during the entire enumeration or catch the exceptions resulting from changes made by other threads.

 

 

9. Initialize collection sizes at startup to speed up node creation.

 

Source URL:

http://robkennedy.com/articles/146.aspx

 

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第9条不怎么明白，是指如下2中情况吗？

ArrayList myAL = new ArrayList(); // Without initializing collection sizes

ArrayList myAL = new ArrayList(1000); // With initializing collection sizes

 

那位帮忙解释一下，Thanks。