Window第一次忽略ShowWindow最小化，然后在每次之后服从

Question

I have a C# application that I am kicking off a separate win32 window from. I'm marshaling Win32 api calls into my C# application and trying to control the win32 from that. I'm toggling the window from a button press to be either maximized on top of all windows always or minimized.

It will show maximized, then ignore the first button press to hide, it then stays showing when I press the button again, then finally hides once I press the button a 3rd time with the same code. It behaves as desired from here on out. I'm sure it must be some Windows flags that aren't set properly until it goes through a maximize/minimize cycle first.

Here is the life cycle of the window:

Create window maximized

A:

Hide:

target_hwnd = FindWindowHandleByCaption()
ShowWindow(target_hwnd, SW_SHOWMINIMIZED);

Show:

target_hwnd = FindWindowHandleByCaption()
ShowWindow(target_hwnd, SW_SHOWMAXIMIZED);

Goto A:

What am I doing wrong? I've been at this for hours trying various code snippets to no avail.

Thanks in advance!

EDIT:

Solved my problem by just doing:

SendMessage(target_hwnd.ToInt32(), WM_SYSCOMMAND, SC_MINIMIZE, 0);

SendMessage(target_hwnd.ToInt32(), WM_SYSCOMMAND, SC_MAXIMIZE, 0);

Instead of using ShowWindow.

Answer 1

Per the ShowWindow() documentation:

nCmdShow
Type: int

Controls how the window is to be shown. This parameter is ignored the first time an application calls ShowWindow , if the program that launched the application provides a STARTUPINFO structure . Otherwise, the first time ShowWindow is called, the value should be the value obtained by the WinMain function in its nCmdShow parameter.

...

The first time an application calls ShowWindow , it should use the WinMain function's nCmdShow parameter as its nCmdShow parameter. Subsequent calls to ShowWindow must use one of the values in the given list, instead of the one specified by the WinMain function's nCmdShow parameter. As noted in the discussion of the nCmdShow parameter, the nCmdShow value is ignored in the first call to ShowWindow if the program that launched the application specifies startup information in the structure . In this case, ShowWindow uses the information specified in the STARTUPINFO structure to show the window. On subsequent calls, the application must call ShowWindow with nCmdShow set to SW_SHOWDEFAULT to use the startup information provided by the program that launched the application. This behavior is designed for the following situations:

• Applications create their main window by calling CreateWindow with the WS_VISIBLE flag set.

• Applications create their main window by calling CreateWindow with the WS_VISIBLE flag cleared, and later call ShowWindow with the SW_SHOW flag set to make it visible.