内存泄漏和处理 [英] Memory leaks and dispose

问题描述

我可能不了解该锥体或我做错了什么. 我对.NET中的内存管理有一些疑问.

May I do not understand the conecept or I do something wrong. I have some questions about the memory management in .NET.

想象一下情况:

Form1是大个子形式，因为MDI父级和一点FormChild被绑定为子级:

Form1 is the big man Form, as MDI-parent and a little FormChild, is bound as child:

public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void simpleButton1_Click(object sender, EventArgs e)
        {
            FormChild formChild = new FormChild();

            formChild.MdiParent = this;
            formChild.Show();

        }
    }

现在孩子正在分配一点内存作为模拟:

Now the child is allocating a little bit memory as simulation:

public partial class FormChild : Form
{
    private readonly List<byte[]> _list = new List<byte[]>();

    public FormChild()
    {
        InitializeComponent();


    }

    private void FormChild_Load(object sender, EventArgs e)
    {
        int i = 0;
        while (i < 100)
        {
            _list.Add(new byte[1024 * 1024 * 10]);
            i += 1;
        }

    }

}

现在，我正在使用内存探查器检查内存堆中发生了什么. 我看到，如果我单击按钮，则会分配内存.然后关闭FormChild，它调用Dispose().但是仍然分配内存.如果我再次单击，则会出现System.OutOfMemoryException.

Now, I'm inspecting with a memory profiler whats going on in the memory heap. I see, if i click on the button, the memory is allocated. Then I close the FormChild and it calls Dispose(). But the memory is still allocated. If I click again a System.OutOfMemoryException occures.

为什么GC等待释放托管内存? 还是这是我的设计错误?

Why is the GC waiting to free the managed memory? Or is this my mistake of design?

推荐答案

它看起来像是一种计时问题，其中formChild的第一个实例仍然可以访问(即，不是垃圾)，而第二个实例已创建.您不能两次容纳该_list.

It looks like some sort of timing problem, where the first instance of formChild is still reachable (ie not garbage) wen the second one is created. You can't accommodate that _list twice.

请注意，我关闭FormChild并调用Dispose()是关于资源和Window句柄的声明，而不是关于释放内存的声明.

Note that I close the FormChild and it calls Dispose() is a statement about resources and Window handles, not about freeing the memory.

尚不清楚您是否编写了自己的Dispose()，但在这种情况下(应该是特殊的情况)，您应该这样做.

It is not clear if you wrote your own Dispose() but in this (rather special) case you should.

• 从FormChild.Designer.cs文件中剪切void Dispose(bool disposing)方法并将其移至FormChild.cs.

• Cut the void Dispose(bool disposing) method from the FormChild.Designer.cs file and move it to FormChild.cs .

使用它释放巨大的内存块:

use it to release the huge memory block:

protected override void Dispose(bool disposing)
{
    _list = null;  // add this

    if (disposing && (components != null))
    {
        components.Dispose();
    }
    base.Dispose(disposing);
}

请注意，这不是内存管理的常规"形式，但因为您的_list也很不正常，所以需要它.

Note that this is not a 'usual' form of memory management but it's needed because your _list is unusual too.

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