WM_APP,Remarks 注意,Requirements,See Also參見,Conceptual相關概念,
WM_APP
Used to define private messages, usually of the form WM_APP+X, where X is an integer value.
用來定義私有訊息,經常以WM_APP+X的格式使用,X是一個整形變數
#define WM_APP 0x8000
Remarks 注意
The WM_APP constant is used to distinguish between message values that are reserved for use by the system and values that can be used by an application to send messages within a private window class.
WM_APP常量是用來把系統預留的訊息值和應用程式視窗類內部使用的訊息區分開來,
The following are the ranges of message numbers available.
下列範圍的訊息代碼可用
Range 範圍 | Meaning 意義 |
0 through WM_USER -1 0 到 WM_USER -1 | Message reserved for use by the system 系統預留使用的 |
WM_USER through 0x7FFF WM_USER 到 0x7FFF | Integer messages for use by private window classes 被私有視窗類使用的整形訊息 |
WM_APP through 0xBFFF WM_APP 到 0xBFFF | Message available for use by applications 可以被應用程式使用的訊息 |
0xC000 through 0xFFFF 0xC000 到 0xFFFF | String messages for use by applications 被應用程式使用的字元串訊息 |
Greater than 0xFFFF 大於0xFFFF | Reserved by the system 系統預留 |
Message numbers in the first range (0 through WM_USER–1) are defined by the system. Values in this range that are not explicitly defined are reserved by the system.
第一個範圍里的訊息代碼(0到WM_USER-1)是被系統定義的,這個範圍內的值.這個範圍內沒有明確定義的值也是系統預留的.
Message numbers in the second range (WM_USER through 0x7FFF) can be defined and used by an application to send messages within a private window class. These values cannot be used to define messages that are meaningful throughout an application, because some predefined window classes already define values in this range. For example, predefined control classes such as BUTTON, EDIT, LISTBOX, and COMBOBOX may use these values. Messages in this range should not be sent to other applications unless the applications have been designed to exchange messages and to attach the same meaning to the message numbers.
