网约车涨价，是“垄断”产物还是理性回归？

Memory leaks do exist and have a profound impact in C#, especially for long-term applications. Common signals include continuous memory rise and frequent GC but no obvious release. They can be analyzed and confirmed by tools such as Visual Studio and dotMemory. The main reasons and solutions are as follows: 1. If you forget to cancel the event subscription, you should manually cancel or use weak references; 2. If the static collection is not cleaned, you need to remove the entry regularly or use WeakReference; 3. If the unmanaged resources are not released, IDisposable should be implemented and using using statements. In addition, understanding the generational GC mechanism and optimizing memory usage such as reducing temporary object creation, rational use of structures, and avoiding LOH fragmentation can also help improve performance. Mastering these key points can effectively deal with memory problems.

Memory leaks and garbage collection are indeed an issue that is easily overlooked but far-reaching in C#. Especially in long-running applications, improper resource management can lead to increased memory usage, which will eventually lead to program crashes or performance degradation. Below are some practical experience summary to help you better deal with these problems.

Identify common signals for memory leaks

C# is a managed language based on .NET, and memory is mainly managed automatically by GC (garbage collector). But even so, memory leaks can still happen. Common signs include:

• The application's memory usage continues to rise and will not be released even after performing the operation.
• GC recycling is frequently triggered, but the memory does not drop significantly.
• Use Visual Studio or PerfMon tools to observe an abnormal increase in the number of objects.

To confirm whether it is a memory leak, it is recommended to use memory analysis tools such as Visual Studio Diagnostic Tools , dotMemory , or PerfView , which can help you see which objects are not recycled in time.

Common causes and solutions for memory leaks

1. Forgot to cancel the event subscription

If you register a static event (such as SomeClass.SomeEvent = MyHandler ) without unsubscribing when no longer needed, the subscriber object will be referenced and cannot be recycled.

? Solution:

• Call manually before object is destroyed -= Unsubscribe;
• Or use weak references to handle events (for example, using WeakEventManager ).

2. Static collection not cleaned

The static field life cycle is as long as the application domain. If objects are added to static lists or dictionaries without cleaning up, these objects will never be recycled.

? Solution:

• Controls the life cycle of static collections;
• Check and remove useless entries regularly;
• Consider using WeakReference to store non-critical objects.

3. Unmanaged resources are not released

If unmanaged resources such as file handles, database connections, image resources, etc. are not released correctly, they will lead to resource leakage.

? Solution:

• Implement the IDisposable interface and call Dispose() after use;
• Use using statement to ensure that resources are released in a timely manner;
• If the class contains unmanaged resources, consider implementing a destructor (Finalizer) as the last line of defense.

Understand the garbage collection mechanism of C#

.NET uses a generational garbage collection mechanism (Gen0, Gen1 and Gen2. The newly created object is allocated in Gen0, and the surviving ones are gradually promoted to higher generations.

GC will be triggered in the following situations:

• Insufficient memory
• Explicitly call GC.Collect()
• When system resources are tight

While you can call GC.Collect() manually, this is not recommended in most cases because this will affect performance. Letting the GC decide for itself when to recycle is usually more efficient.

How to optimize memory usage

In addition to preventing leakage, rationally optimizing memory can also improve application performance:

• Reduce frequent temporary object creation : For example, constantly new objects in a loop will increase GC pressure. Caching or multiplexing objects can be considered.
• Use structures instead of classes (appropriate scenarios) : For small and short life cycle data structures, struct saves more memory than class.
• Avoid large object heap fragmentation (LOH) : Objects greater than 85,000 bytes will be allocated to LOH. GC will not compress this part of the memory and may easily cause fragmentation. Try to avoid frequent allocation and release of large objects.
• Set GC mode reasonably : In high-throughput services, you can try using Server GC mode for better performance.

Basically that's it. Memory management is not a mystery, but it is easy to ignore details. Master several key points and cooperate with tool analysis to solve most of the problems.

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