如何为静态控件设置透明背景？ [英] How to set transparent background for static control?

问题描述

我使用CreateWindowEx（）函数创建了一个窗口。

在这个窗口中我放置了这样创建的静态控件：

I created a window using CreateWindowEx() function.
On this window I place static control which was created like that:

HWND hStatic;
hStatic = CreateWindowEx( WS_EX_TRANSPARENT ,
TEXT("Static"),
TEXT("text"),
WS_CHILD ,
10,
80,
250,
70,
CtrlsWndHnd, //parent
NULL,
hInstance,
NULL);
ShowWindow(hStatic,SW_SHOW);
UpdateWindow(hStatic);

控件已成功创建。

现在我尝试使用此代码创建透明背景：

Control has been successfully created.
And now I try to make transparent background using this code:

//inside parent window procedure:
case WM_CTLCOLORSTATIC:
{
HDC hdcStatic = (HDC) wParam;
SetBkColor(hdcStatic,TRANSPARENT);
return (INT_PTR)(HBRUSH)GetStockObject(NULL_BRUSH);
}
break;

但结果是静态控制的黑色背景。

我做错了什么？错误在哪里？

But result is black background of static control.
What I did wrong? Where is mistake?

推荐答案

我的初步猜测是你需要为控件处理WM_ERASEBKGND消息，并返回非零以指示背景不是需要删除。



它看起来好像你可能自己将背景颜色设置为黑色（SetBkColor采用COLORREF，所以TRANSPARENT可能被解释为黑色或接近黑色的颜色）。您需要将背景模式设置为透明：

My initial guess is that you need to handle the WM_ERASEBKGND message for the control, and return non-zero to indicate that the background doesn't need to be erased.

It also looks as if you are probably setting the background colour to black yourself (SetBkColor takes a COLORREF, so "TRANSPARENT" is probably interpreted as a black, or near black, colour). You need to set the background mode to transparent instead:

SetBkMode (hdcStatic, TRANSPARENT);

但是，根据以下链接，似乎你不应该返回一个空刷，这里提出了完全相同的问题，似乎已经解决了：http://www.cplusplus.com/forum/windows/73999/ [ ^ ]



问候，

Ian。

However, it seems you shouldn't be returning a null brush, according to the following link, where exactly the same question was asked, and seems to be solved: http://www.cplusplus.com/forum/windows/73999/[^]

Regards,
Ian.

Ian A Davidson ，非常感谢！问题在于：

1.而不是：

Ian A Davidson, great thanks! The problem was here:
1. instead of:

SetBkColor(hdcStatic,TRANSPARENT);

需要写：

needed to write:

SetBkMode(hdcStatic,TRANSPARENT);

2。这里我返回了空刷：

2. here I returned null brush:

return (INT_PTR)(HBRUSH)GetStockObject(NULL_BRUSH);

但需要返回有效的背景颜色：

but needed to return valid background color:

HBRUSH BGColorBrush = CreateSolidBrush(RGB(230,230,230));
//...
return (LRESULT)BGColorBrush;

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