VB.net: how do I change the column mapping for an excel sheet when the columns differ?

Private Sub submitBtn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles submitBtn.ServerClick
               Dim fileName As String = xlsFile.PostedFile.FileName
                Dim ConnectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source='" & fileName & "';" & "Extended Properties=""Excel 8.0;HDR=YES;IMEX=1"""
          
Try
 
                Using excelConnection As System.Data.OleDb.OleDbConnection = New System.Data.OleDb.OleDbConnection(ConnectionString)
 
                    excelConnection.Open()
 
                    Using excelCommand As New System.Data.OleDb.OleDbCommand("SELECT * From [Sheet1$]", excelConnection)
 
                        Using destinationConnection As SqlConnection = New SqlConnection(DBAccess.GetConnectionString2)
 
                            destinationConnection.Open()
 
                            Using bulkCopy As SqlBulkCopy = New SqlBulkCopy(destinationConnection)
 
                                Using dr As DbDataReader = excelCommand.ExecuteReader
 
                                    For Each column In dr.GetSchemaTable.Columns
                                        Dim cTemp = CType(column, DataColumn)
                                        bulkCopy.ColumnMappings.Add(New SqlBulkCopyColumnMapping(cTemp.ColumnName, cTemp.ColumnName))
                                    Next
 
                                    bulkCopy.DestinationTableName = "dbo._temp_citypairs"
 
                                    ' Write from the source to the destination.
                                    bulkCopy.WriteToServer(dr)
                                    result.Text = "File upload successful. Thank you."
 
                                End Using
                            End Using
                        End Using
                    End Using
                End Using
 
            Catch ex As Exception
                Response.Write("Exception:" & ex.ToString & "<br>")
            End Try
 
End Sub

                                              

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:
30:
31:
32:
33:
34:
35:
36:
37:
38:
39:
40:
41:
42:

CREATE TABLE [dbo].[_temp_citypairs](
	[id] [int] IDENTITY(1,1) NOT NULL,
	[startloc] [varchar](3) NOT NULL,
	[endloc] [varchar](3) NOT NULL,
	[lcode] [varchar](3) NOT NULL,
	[numstops] [tinyint] NULL,
	[locdata] [bit] NOT NULL CONSTRAINT [DF_temp_citypairs]  DEFAULT (0),
	[startdate] [smalldatetime] NULL,
	[enddate] [smalldatetime] NULL,
	[monday] [bit] NULL,
	[tuesday] [bit] NULL,
	[wednesday] [bit] NULL,
	[thursday] [bit] NULL,
	[friday] [bit] NULL,
	[saturday] [bit] NULL,
	[sunday] [bit] NULL,
	[startloc_new] [varchar](300) NULL,
	[endloc_new] [varchar](300) NULL
) ON [PRIMARY]
 
---------------------------------------------------------------------------
 
Dim fileName As String = xlsFile.PostedFile.FileName
            Dim ConnectionString As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source='" & fileName & "';" & "Extended Properties=""Excel 8.0;HDR=YES;IMEX=1"""
        
 
            Try
 
                Using excelConnection As System.Data.OleDb.OleDbConnection = New System.Data.OleDb.OleDbConnection(ConnectionString)
 
                    Using excelCommand As New System.Data.OleDb.OleDbCommand("SELECT * FROM [Sheet1$] ", excelConnection)
 
                        Using destinationConnection As SqlConnection = New SqlConnection(DBAccess.GetConnectionString2)
 
                            excelConnection.Open()
 
                            Using dr As DbDataReader = excelCommand.ExecuteReader()
 
                                destinationConnection.Open()
 
                                Using bulkCopy As SqlBulkCopy = New SqlBulkCopy(destinationConnection, SqlBulkCopyOptions.UseInternalTransaction, Nothing)
 
                                    For i As Integer = 0 To dr.VisibleFieldCount - 1
                                        bulkCopy.ColumnMappings.Add(New SqlBulkCopyColumnMapping(i, i))
                                    Next
 
                                    bulkCopy.DestinationTableName = "dbo._temp_citypairs"
 
                                    ' Write from the source to the destination.
                                    bulkCopy.WriteToServer(dr)
                                    result.Text = "File upload successful. Thank you."
 
                                End Using
                            End Using
                        End Using
                    End Using
                End Using
 
            Catch ex As Exception
                Response.Write("Exception:" & ex.ToString & "<br>")
            End Try

                                              

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:
24:
25:
26:
27:
28:
29:
30:
31:
32:
33:
34:
35:
36:
37:
38:
39:
40:
41:
42:
43:
44:
45:
46:
47:
48:
49:
50:
51:
52:
53:
54:
55:
56:
57:
58:
59:
60:
61: