ActionDeclareUndo (Function)

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WLanguage functions

Controls, pages and windows

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ActionDeclareUndo (Function)

In french: ActionDeclareUndo

Declares how to cancel an action that was added by ActionDo. This function MUST be called when running the procedure supplied to ActionDo.

Example

ActionDo(WIN_MyEditor, ProcCreateCap, "New")
INTERNAL PROCEDURE ProcCreateCap(sCap)
pNew is Control
pNew <- ControlCreate("STC_" + GetIdentifier(), typText, 150, 150, 80, 20)
pNew..Caption = sCap
ActionDeclareUndo(ProcCancel)
INTERNAL PROCEDURE ProcCancel()
ControlDelete(pNew)
END
END

ActionDeclareUndo(UndoOperation, CUSTOMER.CustomerID)

// Management of Undo
INTERNAL PROCEDURE UndoOperation(nCustomerID)
IF HReadSeekFirst(CUSTOMER, CustomerID, nCustomerID) THEN
SourceToScreen()
END
END

Syntax

ActionDeclareUndo(<WLanguage procedure> [, <Parameter 1> [... [, <Parameter N>]]])

<WLanguage procedure>: Procedure name

Name of WLanguage procedure to run. The code of this procedure must allow to cancel the action created by ActionDo.
This procedure is called when pressing Ctrl + Z or during the call to ActionUndo.
Remark: Using an internal procedure provides a direct access to the local variables.

<Parameter 1>: Any optional type

First optional parameter that will be passed to the procedure.
In most cases, these parameter correspond to values used to restore the previous status.

<Parameter N>: Any optional type

Nth optional parameter that will be passed to the procedure.
In most cases, these parameter correspond to values used to restore the previous status.

Remarks

Use conditions

A WLanguage error occurs if this function is called outside a procedure added by ActionDo.

Component : wd250obj.dll