RegisterClass 失败:类已经存在 [英] RegisterClass failed: class already exits

问题描述

当我第二次创建子窗口时，

When I create a child window for the second time,

if (!::RegisterClass(&hwClass))
{
    throw std::runtime_error("RegisterClass failed!");
}

它抛出一个异常，该类已经存在.但是子窗口类在子窗口被销毁时被删除:

It throws an exception that the class already exists. but the child window class was deleted when the child window was destroyed at:

WM_DESTROY:
{
   delete this;  //destroy child class
}

如果我评论预期错误，它会起作用.这是否意味着我不需要再次注册课程?

It works if I comment the expection error. does that mean I don't need to register a class again?

推荐答案

来自 UnregisterClass 文档，其中指出:

From the UnregisterClass documentation, which states:

在调用此函数之前，应用程序必须销毁使用指定类创建的所有窗口.

Before calling this function, an application must destroy all windows created with the specified class.

表示销毁窗口不会取消注册类.

Indicates that destroying the windows doesn't unregister the class.

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