C memory leak 1: class with dispose method

Reprinted address :https://zhuanlan.zhihu.com/p/365075416

GC and Dispose

C#, Although there are GC System , Can automatically reclaim free memory （ Managed memory ）, But there are many classes Dispose Method , Used to manually and explicitly release the memory occupied by the instance of this class （ Managed and unmanaged memory ）

Unmanaged resources must be explicitly released

Managed memory can wait for the system GC Release , You can also explicitly release , The main significance of explicit release is to control the timing of release , Free up more free memory immediately

Inherit IDisposable Self defined subclass , If a destructor is defined, you can free memory in the destructor , But the destructor is composed of GC Thread calls , Time and sequence are uncontrollable , You can also customize it Dispose Method , Release manually when needed , But I need to tell GC The system has released this resource , And at the same time GC Coordinate the release sequence , Sample code

public class DisposablClass : IDisposable
{
    // Whether the recycling is completed 
    bool _disposed;
    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this); // Mark gc No more calling destructors 
    }
    ~DisposableClass()
    {
        Dispose(false);
    }
    private void Dispose(bool disposing)
    {
        if(_disposed) return; // If it has been recycled , Just interrupt execution 
        if(disposing)
        {
            //TODO: Release the managed resources managed in this object 
        }
        //TODO: Release unmanaged resources 
        _disposed = true;
    }
}

Conditions that may cause memory leaks

1 In explicit call Dispose Before method , Abnormal exit of program

2 There is no destructor defined , But it doesn't show the call Dispose Method

terms of settlement

Use using To create a new class object instance , Sample code

using (var instance = new MyClass())
{
    // ... 
}

The above code is equivalent to , Whether the program is abnormal or not , Will eventually be released instance Of memory

var instance = new MyClass();;
try
{
    // ...
}
finally
{
    if (instance != null)
        instance.Dispose();
}

Reference documents :https://www.cnblogs.com/murongxiaopifu/p/12894385.html
https://www.cnblogs.com/xyzf/p/9021513.html