C Sharp/Object Lifetime
外观
< C Sharp
程序的资源释放有三种方法:
- 受管资源由垃圾回收器自动释放
- 非受管资源,必须实现IDisposable接口,用Dispose方法显式释放
- 调用
System.GC.Collect()
方法直接立即回收垃圾
对于实现了IDisposable的对象,一旦使用完就应该立即显式调用Dispose方法释放资源。using是它的语法糖。
终结器中应该调用Dispose()作为最后的补救措施。
以下为dispose pattern的用例:
public class MyResource : IDisposable
{
private IntPtr _someUnmanagedResource;
private List<long> _someManagedResource = new List<long>();
public MyResource()
{
_someUnmanagedResource = AllocateSomeMemory();
for (long i = 0; i < 10000000; i++)
_someManagedResource.Add(i);
...
}
// The finalizer will call the internal dispose method, telling it not to free managed resources.
~MyResource()
{
this.Dispose(false);
}
// The internal dispose method.
private void Dispose(bool disposing)
{
if (disposing)
{
// Clean up managed resources
_someManagedResource.Clear();
}
// Clean up unmanaged resources
FreeSomeMemory(_someUnmanagedResource);
}
// The public dispose method will call the internal dispose method, telling it to free managed resources.
public void Dispose()
{
this.Dispose(true);
// Tell the garbage collector to not call the finalizer because we have already freed resources.
GC.SuppressFinalize(this);
}
}