如何以编程方式设置静态控件背景颜色 [英] how can I set static controls background color programmatically

问题描述

我想在函数内更改标签背景颜色，我尝试了这段代码，但在调用 changecolor 函数后没有任何改变

I want to change label background color within a function, I tried this code but nothing changed after calling changecolor function

HWND hWndLabel;

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
    case WM_CREATE:
        hWndLabel = CreateWindowEx(WS_EX_TRANSPARENT,
            L"STATIC", L"", WS_CHILD | WS_VISIBLE | SS_LEFT | WS_SYSMENU,
            75, 75, 70, 70, hWnd, (HMENU)labelId, hInst, NULL);
        break;

    case WM_DESTROY:
        PostQuitMessage(0);
        break;

    case WM_COMMAND:  // all events are handled here
        break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
        break;
    }
    return 0;
}

DWORD WINAPI changecolor(){
    HDC hdc = GetDC(hWndLabel); // get context
    SetBkColor(hdc, RGB(0, 0, 230)); // Code Copied from the above answer by cpx.
    return 0;
}

我读到静态控件在它们自己绘制之前会向它们的父级发送 WM_CTLCOLORSTATIC 消息.代码是在 CALLBACK 函数内实现的，但是在调用此代码的地方(更改颜色)?，我如何在函数内调用 SetTextColor

I read that Static controls send their parent a WM_CTLCOLORSTATIC message just before they paint themselves. code is implemented within CALLBACK function, but where this code is called (changing color)?, how can I call SetTextColor within a function

代码示例:

case WM_CTLCOLORSTATIC:
  if (the_button_was_clicked) {
    HDC hdc = reinterpret_cast<HDC>(wParam);
    SetTextColor(hdc, COLORREF(0xFF, 0x00, 0x00));
  }
  return ::GetSysColorBrush(COLOR_WINDOW);  // example color, adjust for your circumstance

推荐答案

尝试更像这样的事情:

HWND hWndLabel;
HBRUSH hBrushLabel;
COLORREF clrLabelText;
COLORREF clrLabelBkGnd;

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
    case WM_CREATE:
        hWndLabel = CreateWindowEx(0, L"STATIC", L"", WS_CHILD | WS_VISIBLE | SS_LEFT,
            75, 75, 70, 70, hWnd, (HMENU)labelId, hInst, NULL);
        hBrushLabel = NULL;
        clrLabelText = GetSysColor(COLOR_WINDOWTEXT);
        clrLabelBkGnd = GetSysColor(COLOR_WINDOW);
        break;

    case WM_DESTROY:
        if (hBrushLabel) DeleteObject(hBrushLabel);
        PostQuitMessage(0);
        break;

    case WM_CTLCOLORSTATIC: {
        HDC hdc = reinterpret_cast<HDC>(wParam);
        SetTextColor(hdc, clrLabelText);
        SetBkColor(hdc, clrLabelBkGnd);
        if (!hBrushLabel) hBrushLabel = CreateSolidBrush(clrLabelBkGnd);
        return reinterpret_cast<LRESULT>(hBrushLabel);
    }

    case WM_COMMAND:  // all events are handled here
        break;

    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
        break;
    }
    return 0;
}

DWORD WINAPI changecolor()
{
    if (hBrushLabel) {
        DeleteObject(hBrushLabel);
        hBrushLabel = NULL;
    }
    clrLabelText = RGB(0xFF, 0x00, 0x00);
    clrLabelBkGnd = RGB(0, 0, 230);
    InvalidateRect(hWndLabel, NULL, TRUE);
    return 0;
}

WM_CTLCOLORSTATIC 文档.

以下 C++ 示例显示了如何设置静态控件的文本前景色和背景色以响应 WM_CTLCOLORSTATIC 消息.hbrBkgnd 变量是初始化为 NULL 的静态 HBRUSH 变量，并在调用 WM_CTLCOLORSTATIC 之间存储背景画笔.当不再需要画笔时，必须通过调用 DeleteObject 函数来销毁画笔，通常是在销毁关联的对话框时.

The following C++ example shows how to set the text foreground and background colors of a static control in response to the WM_CTLCOLORSTATIC message. The hbrBkgnd variable is a static HBRUSH variable that is initialized to NULL, and stores the background brush between calls to WM_CTLCOLORSTATIC. The brush must be destroyed by a call to the DeleteObject function when it is no longer needed, typically when the associated dialog box is destroyed.

case WM_CTLCOLORSTATIC:
    {
    HDC hdcStatic = (HDC) wParam;
    SetTextColor(hdcStatic, RGB(255,255,255));
    SetBkColor(hdcStatic, RGB(0,0,0));

    if (hbrBkgnd == NULL)
    {
        hbrBkgnd = CreateSolidBrush(RGB(0,0,0));
    }
    return (INT_PTR)hbrBkgnd;
    }

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