overloading a function in VB6?

[Scorpion965]

Hello...

I have a function that creates file paths for my program, essentially you would call the function in the following manner:

Dim MyPath as string

MyPath = MyFilePath("myexe.exe")

and MyPath would now be something along the lines of "C:\MyDir\myProgram\myexe.exe"

I also have places where I need just the directory, ie "C:\MyDir\myProgram\", this is where I would like to overload the MyFilePath function to return the file path when it is sent a string and to return the directory when it isn't sent any parameters. This is a simple exercise in other languages but I cannot seem to find an example code snippet for this in VB6, if anyone knows how to overload functions in VB I would appreciate it...

Thanks

[mendhak]

Can you post the code for your function? We might be able to modify it for the same purpose.

[StevenHickerson]

Couldn't you just do this in your MyFilePath fuction..

If trim(strFName) = "" then
     MyFilePath = BaseDirectory
End If
'This is assuming your varialbe is named strFName and your variable holding your directory is BaseDirectory.

Like the above poster said if you post your code we can probably modify it to work.. but I think the above code entered in would work too. Then you just call it as MyPath = MyFilePath("") to get the directory.

[jemidiah]

You could also make it Optional, ex:

Private Function MyFilePath(Optional FilePath As String = "") As String
If FilePath = "" Then
    MsgBox "You didn't pass anything."
Else
    MsgBox "You passed " & FilePath
End If
End Function

I only say this for your future reference, as it does the exact same thing as what's been posted above (except you can pass nothing, ie. MyFilePath() instead of MyFilePath(""), but that's negligable in this case).

Basically, Optional makes the FilePath argument (guess what) optional, meaning if you don't pass it, it doesn't error as it would normally. Now, the '= ""' makes it equal to "" if there is nothing passed for FilePath. Hope this helps in the future

[KayJay]

Or you could use ByRef parameters to return multiple results and have the function return an error code. Windows API work this way.

The example below is unoptimized and more error checking must be done. But I hope it leads you to a viable and correct option to approach your problem.

Private Function MyPathAndFileAndExtensionAndSize(ByRef strFName, ByRef strPName, ByRef strXName, ByRef lngSize) As Long
'Generate an error as the default
MyPathAndFileAndExtensionAndSize = -1
 
'As this can always be retrieved, get it
strPName = App.Path & "\"
 
'If no filename argument is passed then
'only the path is retrieved
'and an error code of 2 is set
'
'If a valid filename is passed then
'the file name is formatted with the path
'the extension is found
'and the file size is retrieved
If Len(strFName) > 0 Then
    strFName = App.Path & "\" & strFName
    strXName = Right$(strFName, Len(strFName) - InStr(1, strFName, ".", vbTextCompare))
    lngSize = FileLen(strFName)
    MyPathAndFileAndExtensionAndSize = 1
Else
    strFName = "No file name passed"
    strXName = "No file name passed"
    lngSize = -1
    MyPathAndFileAndExtensionAndSize = 2
End If
 
End Function
 
 
Private Sub Command1_Click()
Dim strFile As String
Dim strPath As String
Dim strExt As String
Dim lngSize As Long
 
Dim strResult As String
 
strFile = "Form1.frm"
'strFile = ""
 
If MyPathAndFileAndExtensionAndSize(strFile, strPath, strExt, lngSize) <> -1 Then
    strResult = "The fully qualified file name is " & strFile & vbCrLf & vbCrLf
    strResult = strResult & "The path is " & strPath & vbCrLf & vbCrLf
    strResult = strResult & "The extension of the file is " & strExt & vbCrLf & vbCrLf
    strResult = strResult & "The size of the file is " & lngSize & " bytes"
Else
    strResult = "An Error occured"
End If
    
MsgBox strResult
End Sub

HTH

Regards

Kaushik Janardhanan

[DeadEyes]

VB is not an OO language and as such does not support overloading, you'll just have to work around it, using the examples given here or din some other way

[KayJay]

Perhaps the only time a Variant is a *must* in VB6!

[mendhak]

Originally posted by KayJay
Perhaps the only time a Variant is a *must* in VB6!

True, although this feature would have been extremely handy for some of the stuff we do. I'm assuming VB.NET has overloading? Someone correct me if I'm wrong.

[DeadEyes]

VB.NET if fully OO and has overloading, proper inheritance and polymorphism.

[KayJay]

Yep. http://www.dotnetextreme.com/code/FuncOverLoad.asp

[MartinLiss]

Originally posted by KayJay
Perhaps the only time a Variant is a *must* in VB6!

What do you mean?

[KayJay]

A better example than any thing I could whip up!

http://www.vb-faq.com/Articles/Zimme...omingVB7_3.asp

Check out the hyperlink in the para begining with "Overloading permits more elegance.."

Also take a look at this discussion

VB6 does not support function overloading. (You can try looking into
ParamArray and the Variant data type; these might allow you to simulate
function overloading.)

Long and short of it, only a Variannt can accomodate multiple data types for parameters (unless one takes into consideration a ParamArray) which FAPP and perhaps even theoratically a Variant.

HTH

Regards

Kaushik Janardhanan

[mendhak]

Originally posted by MartinLiss
What do you mean?

To work with different datatypes. Declare a function with the argument as a variant, check it's datatype, and perform different tasks based upon what type it is. So you can OBJECTNAME.add(something1, something2) with strings, integers, etc.

That's one example.

[KayJay]

Oops! Missed out on the google groups links

http://groups.google.co.in/groups?hl...3Dwg%26meta%3D

http://groups.google.co.in/groups?hl...3Dwg%26meta%3D