EM_UNDO message
This message undoes the last edit control operation in the control's undo queue. You can send this message to either an edit control or a rich edit control.
Parameters
-
wParam
-
Not used; must be zero.
-
lParam
-
Not used; must be zero.
Return value
For a single-line edit control, the return value is always TRUE.
For a multiline edit control, the return value is TRUE if the undo operation is successful, or FALSE if the undo operation fails.
Remarks
Edit controls and Rich Edit 1.0: An undo operation can also be undone. For example, you can restore deleted text with the first EM_UNDO message, and remove the text again with a second EM_UNDO message as long as there is no intervening edit operation.
Rich Edit 2.0 and later: The undo feature is multilevel so sending two EM_UNDO messages will undo the last two operations in the undo queue. To redo an operation, send the EM_REDO message.
Rich Edit: Supported in Microsoft Rich Edit 1.0 and later. For information about the compatibility of rich edit versions with the various system versions, see About Rich Edit Controls.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client |
Windows Vista [desktop apps only] |
| Minimum supported server |
Windows Server 2003 [desktop apps only] |
| Header |
|