Optional X as Boolean = ??? to detect missing argument?

[Joe HM]

Hello -

I realize that there is no more IsMissing function in VB.NET but how
can I have a boolean argument that is optional and in the code I need
to determine whether it was passed it or not?

I use the Single.NaN to set the default values for some of my optional
single arguments so that I can determine whether an argument was passed
it ... but that does not work for booleans.

Any suggestions?

Thanks!
Joe

 

[Melissa Nava]

Are you working with checkboxes?

If you are you can use a threestate property - it would put it to
checked, unchecked or indeterminate...

http://msdn2.microsoft.com/en-US/library/system.windows.forms.checkbox.threestate.aspx

 

[Jay B. Harlow [MVP - Outlook]]

Joe,
In the case of needing "missing" value types (Single, Integer, Boolean) I
normally overload the method instead of using optional parameters.

Public Sub Something()
' Boolean parameter not passed
End Sub

Public Sub Something(flag As Boolean)
' Boolean parameter was passed
End Sub

Depending on how the extra parameter is used, I may call the first from the
second or visa versa.

I reserve Optional parameter when I have a clear default value.

Public Sub SetDirty(Optional flag As Boolean = True)
' defaults to setting Dirty to true
End Sub

SetDirty() ' set the object to dirty

SetDirty(False) ' the object is now clean...

--
Hope this helps
Jay B. Harlow [MVP - Outlook]
..NET Application Architect, Enthusiast, & Evangelist
T.S. Bradley - http://www.tsbradley.net


| Hello -
|
| I realize that there is no more IsMissing function in VB.NET but how
| can I have a boolean argument that is optional and in the code I need
| to determine whether it was passed it or not?
|
| I use the Single.NaN to set the default values for some of my optional
| single arguments so that I can determine whether an argument was passed
| it ... but that does not work for booleans.
|
| Any suggestions?
|
| Thanks!
| Joe
|

 

[Joe HM]

Hello Jay -

Thanks for the input ... I guess that is probably the best way to go.

Joe

 

[Joe HM]

Hello Melissa -

Thanks for you response. I am not dealing with checkboxes but that is
something I should look into.

Thanks!
Joe