How To Implement Array Arguments in Visual Basic COM Objects for Active Server Pages

This step-by-step article describes how to implement arrays to be passed as parameters from Active Server Pages (ASP) to a Visual Basic Component Object Model (COM) Object.

Array Argument Declarations

IMPORTANT: If array arguments are for methods, they must be declared as variant data type and must be passed by reference. If you declare an array argument as any other type, you may receive one of the following error messages: -or-

-or-

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Implement Arrays

Follow these steps to implement arrays to be passed as parameters from ASP to a Visual Basic COM Object:

1. From the Microsoft Windows Start menu, point to Programs, point to Microsoft Visual Studio 6.0, and then click Microsoft Visual Basic 6.0 to open Visual Basic.
2. In the New Project dialog box, click ActiveX DLL, name it "ASPArray" (without quotation marks), and then click Open.
3. From the Project menu, click Project Properties, click to select the Unattended Execution and the Retained in Memory check boxes, and then click OK.
4. Change the name of the class module to "clsArray" (without quotation marks).
5. Implement the following function:

   Public Function TestArray( ByRef vArray as Variant ) as String
     Dim nCnt as integer
   
     'Verify that the argument passed is an array
     If Not IsArray( vArray ) Then
       TestArray = "Parameter is not an Array"
       Exit Function
     End If
   
     For nCnt = LBound(vArray) to UBound(vArray)
         'Traverse Array Element        
     Next nCnt
       
     TestArray = "Parameter is an Array"
   End Function
   					

6. Create an ASP page with the following code:

   <%
     Dim oTestObj, vMyArray(2), vRtnValue
           
     vMyArray(0) = "Element 1"
     vMyArray(1) = "Element 2"
     vMyArray(2) = "Element 3"
   
     Set oTestObj = Server.CreateObject("ASPArray.clsArray")
     vRtnValue = oTestObj.TestArray( vMyArray )
     Response.Write( "Return Value = " & vRtnValue )
   %>