int WINAPI MessageBox ( _In_opt_ HWND hWnd, _In_opt_ LPCTSTR lpText, _In_opt_ LPCTSTR lpCaption, _In_ UINT uType );Parameters 参数
- hWnd [in, optional] 窗口句柄
Type（类型）: HWND
A handle to the owner window of the message box to be created. If this parameter is NULL, the message box has no owner window.
这个句柄属于创建这个MessageBox的窗体的句柄，如果为空，则没有，默认是以桌面为父窗口。
- lpText [in, optional] 内容
Type（类型）: LPCTSTR
The message to be displayed. If the string consists of more than one line, you can separate the lines using a carriage return and/or linefeed character between each line.
显示对话框消息内容，如果有多行，用回车换行符（ ）分成多行。
- lpCaption [in, optional] 标题
Type（类型）: LPCTSTR
The dialog box title. If this parameter is NULL, the default title is Error.
显示对话框标题，如果参数是NULL，则默认标题为Error。
uType [in]
Type: UINT
The contents and behavior of the dialog box. This parameter can be a combination of flags from the following groups of flags.
这个参数表明这个对话框的内容和行为。这个参数可以由一个标志和一个标志组组成。
To indicate the buttons displayed in the message box, specify one of the following values.
要想指明这个消息框的显示按钮，需要确定下列的值。
Value Meaning
- MB_ABORTRETRYIGNORE
- 0x00000002L
The message box contains three push buttons: Abort, Retry, and Ignore.
这个消息框包含三个按钮：Abort，Retry,Ignore.
- MB_CANCELTRYCONTINUE
- 0x00000006L
The message box contains three push buttons: Cancel, Try Again, Continue. Use this message box type instead of MB_ABORTRETRYIGNORE.
这个消息框包含三个按钮：Cancek,Try Again,Continue.可以用MB_ABORTRETRYIGNORE代替。
- MB_HELP
- 0x00004000L
Adds a Help button to the message box. When the user clicks the Help button or presses F1, the system sends a WM_HELP message to the owner.
给消息框添加一个Help Button.当用户点击这个按钮或者按下F1时，系统会向他的父窗口发送一条WM_HTLP消息。
- MB_OK
- 0x00000000L
The message box contains one push button: OK. This is the default.
给消息框添加一个OK按钮，如果为NULL，默认就是MB_OK。
- MB_OKCANCEL
- 0x00000001L
The message box contains two push buttons: OK and Cancel.
- MB_RETRYCANCEL
- 0x00000005L
The message box contains two push buttons: Retry and Cancel.
- MB_YESNO
- 0x00000004L
The message box contains two push buttons: Yes and No.
- MB_YESNOCANCEL
- 0x00000003L
The message box contains three push buttons: Yes, No, and Cancel.
To display an icon in the message box, specify one of the following values.
消息框添加展示图标，需要确定以下的值：
To indicate the default button, specify one of the following values.
制定默认按钮，需要确定以下的值：
To indicate the modality of the dialog box, specify one of the following values.
指定这个对话框的模式，需要确定以下的值：
To specify other options, use one or more of the following values.
确定其他选项，使用以下值：
Value Meaning
- MB_DEFAULT_DESKTOP_ONLY
- 0x00020000L
Same as desktop of the interactive window station. For more information, see Window Stations.
If the current input desktop is not the default desktop, MessageBox does not return until the user switches to the default desktop.
和交互窗口类似，if现在的输入桌面不是默认桌面，消息框不会返回直到用户切换默认桌面。
- MB_RIGHT
- 0x00080000L
The text is right-justified.
这些文字是向右对齐。
- MB_RTLREADING
- 0x00100000L
Displays message and caption text using right-to-left reading order on Hebrew and Arabic systems.
显示消息框和标题从右到左的阅读方式。
- MB_SETFOREGROUND
- 0x00010000L
The message box becomes the foreground window. Internally, the system calls the SetForegroundWindow function for the message box.
消息框变成前景窗口，内部原理，操作系统调用SetForegroundWindow函数为这个消息框。
- MB_TOPMOST
- 0x00040000L
The message box is created with the WS_EX_TOPMOST window style.
消息框被创建具有WS_EX_TOPMOST这个分格。
- MB_SERVICE_NOTIFICATION
- 0x00200000L
The caller is a service notifying the user of an event. The function displays a message box on the current active desktop, even if there is no user logged on to the computer.
调用者是一个提醒一个拥有事件的用户服务。这个函数显示了在当前桌面的消息框，甚至是否有用户登录当前电脑。
Terminal Services: If the calling thread has an impersonation token, the function directs the message box to the session specified in the impersonation token.
终端服务：如果调用线程有一个口令，这个函数会直接使用这个消息框对于这个被当前口令确定的回话。
If this flag is set, the hWnd parameter must be NULL. This is so that the message box can appear on a desktop other than the desktop corresponding to the hWnd.
For information on security considerations in regard to using this flag, see Interactive Services. In particular, be aware that this flag can produce interactive content on a locked desktop and should therefore be used for only a very limited set of scenarios, such as resource exhaustion.
如果这个标志被设定，这个hWnd参数必须是NULL。以便于消息框可以出现在桌面上不是桌面对应的窗口句柄。
更多有关安全方面的消息要注意这个标志了，参考Interactive Services。
Return value（返回值）
Type（类型）: int
If a message box has a Cancel button, the function returns the IDCANCEL value if either the ESC key is pressed or the Cancel button is selected. If the message box has no Cancel button, pressing ESC has no effect.
如果消息框拥有Cancel按钮，这个函数将会返回IDCANCEL值，如果ESC键位被按下或者Cancel按钮被选中。如果消息框没有这个Cancel按钮，那么按ESC也不会有效果。
If the function fails, the return value is zero. To get extended error information, call GetLastError.
如果函数调用失败，那么返回0.获得跟多错误消息，可以调用GetLastError（）这个函数。
If the function succeeds, the return value is one of the following menu-item values.
如果函数成功，那么返回下面的一些值：
Return code/value Description
- IDABORT
- 3
The Abort button was selected.
- IDCANCEL
- 2
The Cancel button was selected.
- IDCONTINUE
- 11
The Continue button was selected.
- IDIGNORE
- 5
The Ignore button was selected.
- IDNO
- 7
The No button was selected.
- IDOK
- 1
The OK button was selected.
- IDRETRY
- 4
The Retry button was selected.
- IDTRYAGAIN
- 10
The Try Again button was selected.
- IDYES
- 6
The Yes button was selected.