A checkbox value is logical. Try the following:

cTblName = LEFT(THIS.TAG, I - 1)
USE Table1 ORDER 2 && You should use the name of the index here, it's clearer

IF SEEK(UPPER(cTblName))
   REPLACE FLAG WITH This.Value
   *-- Type mismatch. <- What is the type of the field? It should be Logical
ENDIF

USE

HTH

---

>I cannot solve the problem in following code. It is the event handle of CheckBox.Click.
>
>cTblName = LEFT( THIS.TAG, i - 1 )
>
>USE table1 ORDER 2
>SEEK UPPER( cTblName )
>IF FOUND( )
> IF ( this.Value = 1 ) <-ERROR: operator/operand
> REPLACE FLAG WITH .T. type mismatch.
>
> ELSE
> REPLACE FLAG WITH .F.
> ENDIF
>ENDIF
>USE