Optional Parameter default value can't be set?

[VBCrazyCoder]

Hi all,

Anyone know how I can do the following:

Public Sub SomeMethod(ByVal strString As String, Optional ByVal bytArray() As Byte = {12, 13, 14})

I get a squigly under the first { telling me "Expression Expected".

Any ideas? I would rather not overload the method t get around this if I don't have to.

Thanks.

[Pirate]

I was trying to do the same couple of days ago but I couldn't . You can't intialize optionl parameters within method signature .

[VBCrazyCoder]

I can do it for strings and integers and the like, but not for the byte array for some reason. (I am using VS.NET 2003).

[Pirate]

Uh..VS.NET2003 support that ? Can you post little sample for that ! I've tried with VS2002 but didn't work .

[VBCrazyCoder]

For example, you can do this:

Public Sub MySub(ByVal strString As String, Optional ByVal strOptional As String = "String", _
        Optional ByVal intOptional As Integer = 6)
End Sub

I don't know why I couldn't do the array though.

[Pirate]

This is what I wanted to do :

Public Sub MySub(ByVal strString As String, Optional ByVal Path_ As String = Application.StartupPath & "file.xxx")
 
End Sub

Did you try make them ByRef ? because arrays are referenced values not like other data types .

[Lunatic3]

From MSDN:

defaultvalue
Required for Optional arguments. Any constant or constant expression that evaluates to the data type of the argument. If the type is Object, or a class, interface, array, or structure, the default value can only be Nothing.

[VBCrazyCoder]

Sweet! Thanks. I'll just check for nothing and use a private class byte array instead!

[Edneeis]

If you have to test for Nothing then it'd seem better to overload the method:

Public Sub SomeMethod(ByVal strString As String)
   Dim bytArray() As Byte = {12, 13, 14}
   Me.SomeMethod(strString,bytArray)
End Sub
 
Public Sub SomeMethod(ByVal strString As String, ByVal bytArray() As Byte)
 
End Sub

Actually I try to avoid the Optional Argument in favor of Overloading.

[VBCrazyCoder]

If I overloaded, then the method that takes doesn't take the array would simply call the one that did with the array defined in the class.

I think in my case it makes more sense just to use the optional parameter and then have one line:

If arr Is Nothing Then arr = myClassArray

From what I have heard, optional parameters are converted into overloaded methods when compiled. Not sure if this is true, but it would make sense.