如何初始化句柄 [英] How to Initialise a Handle

问题描述

错误：

Run-Time Check Failure #3 - The variable 'TextLabelVar' is being used without 
being initialized.

说明代码：

HWND VarText;
char Disps[100];
float some_number;
WINAPI WndProc(..)
{   

    switch(...) 
    case WM_CREATE:
    TextLabelVar=CreateWindowEx(WS_EX_WINDOWEDGE,TEXT("Edit"), TEXT("Val."), WS_CHILD \
                | WS_VISIBLE, 380, 50, 140, 20, hwnd, NULL, NULL, NULL);
    break;

    case WM_MESSAGEFROMANOTHERWINDOW:
    some_number=1298.123123;
    sprintf(Disps,"%f",some_number);
    SetWindowText(TextLabelVar,TEXT(Disps));

}

问题：
好​​的，我得到错误TextLabelVar正在使用，无需初始化。我得到类似的错误var Disps。然后我声明char Disps [100];这显示没有错误。现在，错误移动到句柄。我不知道我可以声明一个句柄作为数组，这是有道理的。我如何解决这个问题？

Question: Ok, I get the error TextLabelVar is being used without initialisation. I got similar error for var Disps. I then declared char Disps[100]; This showed no error. Now, the error moves onto a handle. I am not sure I can declare a handle as array and it makes sense. How do I solve this?

推荐答案

这是一个运行时错误。它告诉你在它被初始化之前，正在读取 TextLabelVar 。这意味着 WM_MESSAGEFROMANOTHERWINDOW 在 WM_CREATE 之前执行的case语句。

This is a run-time error. What it is telling you is that TextLabelVar is being read before it has been initialised. And that means that the WM_MESSAGEFROMANOTHERWINDOW case statement executed before WM_CREATE.

从您分配 0 到 TextLabelVar 的注释中删除警告，到 SetWindowText 无法成功，因为您传递的窗口句柄是 0 。

From the comments you've assigned 0 to TextLabelVar to suppress the warning, but then of course the call to SetWindowText cannot succeed since the window handle you pass is 0.

要解决这个问题，您需要了解为什么 WM_MESSAGEFROMANOTHERWINDOW 正在 WM_CREATE 之前处理。

To tackle the problem you need to understand why WM_MESSAGEFROMANOTHERWINDOW is being handled before WM_CREATE.

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