PRB: "Error Loading DLL" When Returning User Defined Data Type from VB COM Object (224397)


The information in this article applies to:

  • Microsoft Active Server Pages
  • Microsoft Visual Basic Learning Edition for Windows 5.0
  • Microsoft Visual Basic Learning Edition for Windows 6.0
  • Microsoft Visual Basic Professional Edition for Windows 5.0
  • Microsoft Visual Basic Professional Edition for Windows 6.0
  • Microsoft Visual Basic Enterprise Edition for Windows 5.0
  • Microsoft Visual Basic Enterprise Edition for Windows 6.0
  • Microsoft Internet Information Server 4.0
  • Microsoft Internet Information Server 5.0
This article was previously published under Q224397

SYMPTOMS

When returning an Array or Collection of user defined data types (UDTs) from a Visual Basic COM object to Active Server Pages (ASP), the following error may occur:
Microsoft VBScript runtime error '800a0030'
Error Loading DLL: TestMethod

CAUSE

User defined data types are not supported in the current version of ASP.

RESOLUTION

Since ASP does not support UDTs, you can work around this by creating a new class to handle the data in place of the UDT and setting the instancing property to PublicNotCreateable. This will ensure that you can pass the necessary information to and from ASP, as well as that the class cannot be created outside of the DLL.

STATUS

This behavior is by design.

MORE INFORMATION

Steps to Reproduce Behavior

  1. Create a Visual Basic ActiveX DLL Project called "VBUDTPrj."
  2. Add class module called "VBUDTObj."
  3. Define a user defined data type as follows: 
         
Public Type TestUDT
   strName as String
   strDept as String  
End Type
  4. Implement the following method: 
    Public Function TestMethod()As Variant
  Dim rtnArray(10) As Variant
  Dim intCnt As Integer
  For intCnt = 0 To 9
    Dim udtTestData As TestUDT
    udtTestData.strName = "Name"
    udtTestData.strDept = "Department"
    rtnArray(intCnt) = udtTestData
  Next
  TestMethod = rtnArray
End Function
  5. Create an ASP Page that calls this Method: 
      <%
    Dim objTest, udtArray, udtData
    Set objTest = Server.CreateObject("VBUDTPrj.VBUDTObj")
    udtArray = objTest.TestMethod()
    udtData = udtArray(1)  
    Response.Write( "Name = " & udtData.strName & "<BR>" )
    Response.Write( "Dept = " & udtData.strDept & "<BR>" )
  %>
  6. Run the ASP page and the following error occurs:
    Microsoft VBScript runtime error '800a0030'
    Error Loading DLL: TestMethod

REFERENCES

Refer to the TYPE statement in the Visual Basic Documentation.
Modification Type:MajorLast Reviewed:6/29/2004
Keywords:kberrmsg kbprb KB224397
©2004 Microsoft Corporation. All rights reserved.