How To Get Primary Key (Columns) Of A Table?

I want to get the Primary Key Columns in Arrays by sending a table

name. I am using SQL Server 2000 and I want to make a find utility in VB.net which
will work for all the forms; I have tables with one Primary key and some tables with composite Primary keys.

I used to do this in VB 6 by making a function which fills the Primary Keys in
List Box (I require to fill in list box), now I need to get in array.

Can some one tell me the migration of the following VB 6 Code?

This was written for the MS Access, I need same for SQL Server, I can
not find Table Def and Index Object in VB.net 2003.

Public Sub GetFieldsFromDatabase (ldbDatabase As Database, lsTableName As
String)
   
  Dim lttabDef As TableDef
  Dim liCounter As Integer
  Dim liLoop As Integer
  Dim idxLoop As Index
  Dim fldLoop As Field


  With ldbDatabase
    For Each lttabDef In .TableDefs
      If lttabDef.Name = lsTableName Then
        liCounter = lttabDef.Fields.Count
        For liLoop = 0 To liCounter - 1
          cboFieldLists.List(liLoop) = lttabDef.Fields(liLoop).Name
        Next liLoop
        For Each idxLoop In lttabDef.Indexes
          With idxLoop
            lblIndexName = .Name
            If .Primary Then
              liCounter = 0
              For Each fldLoop In .Fields
               cboPrimaryKeys.List(liCounter) = fldLoop.Name
                liCounter = liCounter + 1
              Next fldLoop
            End If
          End With
        Next
        cboFieldLists.ListIndex = 0
        If cboPrimaryKeys.ListCount > 0 Then
          cboPrimaryKeys.ListIndex = 0
        End If
        Exit For
      End If
     Next
 End With
End Sub