MdispHookFunction
| MIL_ID DisplayId, | //in |
| MIL_INT HookType, | //in |
| MIL_DISP_HOOK_FUNCTION_PTR HookHandlerPtr, | //in |
| void *UserDataPtr | //in |
This function allows you to attach or detach a user-defined function to a specified display event. Once a hook-handler function is defined and hooked to an event, it is automatically called when the event occurs.
You can hook more than one function to an event by making separate calls to MdispHookFunction() for each function that you want to hook. MIL automatically chains and keeps an internal list of all these hooked functions. When a function is hooked, this new function is added to the end of the list. When the event happens, all user-defined functions in the list will be executed in the same order that they were hooked to the event. You can also remove any function from the list; in this case, MIL preserves the order of the remaining functions in the list.
Note that this function is not available on network displays.
Specifies the display event type. This parameter can be set to the following:
For specifying the display event
type |
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  Value |
Description
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| M_KEY_CHAR + |
Calls the hook-handler function each time the user presses a keyboard key, while the mouse cursor is in the display. |
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| M_KEY_UP
+ |
Calls the hook-handler function each time the user releases a keyboard key, while the mouse cursor is in the display. |
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| M_MOUSE_LEFT_BUTTON_DOWN + |
Calls the hook-handler function each time the user clicks the left mouse button, while the mouse cursor is in the display. |
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| M_MOUSE_LEFT_BUTTON_UP + |
Calls the hook-handler function each time the user releases the left mouse button, while the mouse cursor is in the display. |
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| M_MOUSE_LEFT_DOUBLE_CLICK + |
Calls the hook-handler function each time the user double-clicks the left mouse button, while the mouse cursor is in the display. |
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| M_MOUSE_MIDDLE_BUTTON_DOWN + |
Calls the hook-handler function each time the user clicks the middle mouse button, while the mouse cursor is in the display. |
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| M_MOUSE_MIDDLE_BUTTON_UP + |
Calls the hook-handler function each time the user releases the middle mouse button, while the mouse cursor is in the display. |
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| M_MOUSE_MOVE + |
Calls the hook-handler function each time the mouse cursor moves, while in the display. |
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| M_MOUSE_RIGHT_BUTTON_DOWN + |
Calls the hook-handler function each time the user clicks the right mouse button, while the mouse cursor is in the display. |
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| M_MOUSE_RIGHT_BUTTON_UP + |
Calls the hook-handler function each time the user releases the right mouse button, while the mouse cursor is in the display. |
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| M_MOUSE_WHEEL + |
Calls the hook-handler function each time the user scrolls the mouse wheel (up or down), while the mouse cursor is in the display. |
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You can add the following value to the above-mentioned values to set whether to detach the hook-handler function.
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For detaching the hook-handler
function |
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| Combination value |
Description
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M_UNHOOK |
Unhooks the specified function if hooked to the specified event. |
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Specifies the address of the function that should be called when the specified event occurs. The hook-handler function, pointed to by HookHandlerPtr, must be declared as follows:
Type of event hooked.
Reserved for future use.
Data pointer that was passed to MdispHookFunction().
Upon successful completion, the hook-handler function should return M_NULL. Note, MFTYPE and MIL_DISP_HOOK_FUNCTION_PTR are reserved MIL predefined types for functions and data pointers.
Specifies the address of the user data that you want to make available to the hook-handler function. This address is passed to the hook-handler function, through its UserDataPtr parameter, when the specified event occurs. Set this parameter to M_NULL if not used.
| Header | Include mil.h. |
| Library | Use mil.lib. |
| DLL | Requires mil.dll; mildisplay.dll. |