MessageBox

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：

Value	Meaning
MB_ICONEXCLAMATION 0x00000030L	An exclamation-point icon appears in the message box. 显示一个惊叹号图标。
MB_ICONWARNING 0x00000030L	An exclamation-point icon appears in the message box.
MB_ICONINFORMATION 0x00000040L	An icon consisting of a lowercase letter i in a circle appears in the message box. 这个消息框里面有一个：圆圈里面包含小写字母i.
MB_ICONASTERISK 0x00000040L	An icon consisting of a lowercase letter i in a circle appears in the message box.
MB_ICONQUESTION 0x00000020L	A question-mark icon appears in the message box. The question-mark message icon is no longer recommended because it does not clearly represent a specific type of message and because the phrasing of a message as a question could apply to any message type. In addition, users can confuse the message symbol question mark with Help information. Therefore, do not use this question mark message symbol in your message boxes. The system continues to support its inclusion only for backward compatibility. 一个问号图标在消息框上。系统任然支持这个图标，但是不建议使用它，因为，它象征一个不明确的类型。
MB_ICONSTOP 0x00000010L	A stop-sign icon appears in the message box. 一个stop符号的图标。
MB_ICONERROR 0x00000010L	A stop-sign icon appears in the message box.
MB_ICONHAND 0x00000010L	A stop-sign icon appears in the message box.

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：

Value	Meaning
MB_DEFBUTTON1 0x00000000L	The first button is the default button. MB_DEFBUTTON1 is the default unless MB_DEFBUTTON2, MB_DEFBUTTON3, or MB_DEFBUTTON4 is specified. 这个是默认按钮，MB_DEFBUTTON2, MB_DEFBUTTON3, or MB_DEFBUTTON4除非被添加。
MB_DEFBUTTON2 0x00000100L	The second button is the default button.
MB_DEFBUTTON3 0x00000200L	The third button is the default button.
MB_DEFBUTTON4 0x00000300L	The fourth button is the default button.

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：

Value	Meaning
MB_APPLMODAL 0x00000000L	The user must respond to the message box before continuing work in the window identified by the hWnd parameter. However, the user can move to the windows of other threads and work in those windows. 用户必须响应消息框在hWnd参数被确定下来之前，用户可以移动其他线程的窗口和当前工作窗口。 Depending on the hierarchy of windows in the application, the user may be able to move to other windows within the thread. All child windows of the parent of the message box are automatically disabled, but pop-up windows are not. 依赖于这个程序的窗口继承，用户可以移动其他包含线程的窗口。所有的父窗口的子窗口是自动显示的，但是右键窗口不是。 MB_APPLMODAL is the default if neither MB_SYSTEMMODAL nor MB_TASKMODAL is specified. MB_APPLMODAL是默认参数，除非MB_SYSTEMMODAL和MB_TASKMODAL被添加。
MB_SYSTEMMODAL 0x00001000L	Same as MB_APPLMODAL except that the message box has the WS_EX_TOPMOST style. Use system-modal message boxes to notify the user of serious, potentially damaging errors that require immediate attention (for example, running out of memory). This flag has no effect on the user's ability to interact with windows other than those associated with hWnd. 和MB_APPLMODAL相似，除非消息框有WS_EX_TOPMOST这个分格。使用系统模态消息框通知用户严重和潜在性的错其，并且要求用户立即注意此问题，例如：内存不够用。这些标志不会影响用户和Windows的交互操作，仅仅和hWnd句柄有关系。
MB_TASKMODAL 0x00002000L	Same as MB_APPLMODAL except that all the top-level windows belonging to the current thread are disabled if the hWnd parameter is NULL. Use this flag when the calling application or library does not have a window handle available but still needs to prevent input to other windows in the calling thread without suspending other threads. 和MB_APPLMODAL相似，除非所有的置顶窗口属于当前的线程没有被激活，如果hWnd这个参数为NULL。当调用exe或者dll时使用这个标志并不会有一个可用的窗口句柄，但是需要保护输入到其他窗口在调用线程并且其他线程没有挂起。

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.