如何更改组合框的背景颜色

Question

如何使用Windows API在C ++中更改组合框的背景颜色？

Answer 1

通常，您可以在堆中创建画笔，例如使用

static HBRUSH hbrush;
...
hbrush = CreateSolidBrush(RGB(255,0,0));

然后在Window或Dialog过程中，处理WM_CTL***消息并返回画笔句柄，例如

case WM_CTLCOLORBTN:
case WM_CTLCOLORSTATIC:
case WM_CTLCOLOREDIT:
case WM_CTLCOLORLISTBOX:
{
    HDC hdc = (HDC)wParam;
    SetTextColor(hdc, RGB(0, 0, 255)); //change text color
    SetBkMode(hdc, TRANSPARENT); //change text-background color, or set it to transparent
    return (INT_PTR)hbrush;
}

这也适用于ComboBox。如果您想单独处理不同的控件，可以针对控件的句柄检查lParam。

对于ComboBox来说，它有点复杂。你必须获得ComboBox的EditBox和ListBox的句柄。您可以使用GetComboBoxInfo

执行此操作

case WM_CTLCOLOREDIT:
case WM_CTLCOLORLISTBOX:
{
    HWND hTest = (HWND)lParam;
    COMBOBOXINFO ci = { sizeof(COMBOBOXINFO) };
    GetComboBoxInfo(hComboBox, &ci);

    if (
        hTest == ci.hwndItem ||
        hTest == ci.hwndList
        )
    {
        HDC hdc = (HDC)wParam;
        SetTextColor(hdc, RGB(0, 0, 255));
        SetBkMode(hdc, TRANSPARENT);
        return (INT_PTR)hbrush;
    }
}