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IsMissing Function
This standard VB function is used to determine whether an optional argument for a procedure has been supplied by the caller.
Syntax
IsMissing(argname)
Argument Description argname An optional argument for a subprogram, function, Siebel VB statement, or Siebel VB function
Returns
-1 (TRUE) if an optional parameter was not supplied by the user; 0 (FALSE) otherwise.
Usage
IsMissing is used in procedures that have optional arguments to find out whether the argument's value was supplied or not.
Example
This example prints a list of uppercase characters. The quantity printed is determined by the user. If the user wants to print every character, the Function
myfunc
is called without any argument. The function uses IsMissing to determine whether to print every uppercase character or just the quantity specified by the user.Function myfunc(Optional arg1)
If IsMissing(arg1) = -1 then
arg1 = 26
End If
msgtext = "The letters are: " & Chr$(10)
For x = 1 to arg1
msgtext = msgtext & Chr$(x + 64) & Chr$(10)
Next x
End FunctionSub Button_Click
Dim arg1
arg1 = 0
If arg1 = 0 then
myfunc()
Else
myfunc(arg1)
End If
End SubSee Also
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Siebel VB Language Reference Published: 18 June 2003 |