Get FlatFile Columns Through ConnectionManager

The CreatePackage sample provided with SQL Server programmatically creates a package that has a source type of OLEDB to a flat file destination. I am building exactly the opposite, source=flatfile, destination=SQL Server. I expect that will be a more common scenario is using SSIS.

The problem I have is populating the source columns in the FlatFileSource connection manager programmatically. I know it can be done because it happens when you build a package in Visual Studio. What I'd like to know is how to do it programmatically in the object model. How can I interrogate the datasource through the connection manager to find out what columns it has? If I know, I can add the columns to the connection manager. My sample below does this, but it doesn't know the number of columns in the source so that value is hardcoded. I'm guessing there is a better way to do this than what I've got below.

How can I find the number of columns in my source so I can add the columns to the connection manager?

Thanks.



Private Sub AddColumnsToFlatFileConnectionManager()
Dim ff As wrap.IDTSConnectionManagerFlatFile90 = Nothing

For Each cm As ConnectionManager In _Package.Connections
If cm.Name.Equals(_ExternalConnectionID) Then
ff = TryCast(cm.InnerObject, wrap.IDTSConnectionManagerFlatFile90)
DtsConvert.ToConnectionManager90(cm)
End If
Next

If Not ff Is Nothing Then

Dim col As wrap.IDTSConnectionManagerFlatFileColumn90
Dim name As wrap.IDTSName90
Dim Min As Int32 = 0
Dim Max As Int32 = Min + 3 ' *** HARDCODED LIMIT ***

For cols As Integer = Min To Max
col = ff.Columns.Add()

If cols = Max Then
col.ColumnDelimiter = vbCrLf
Else
col.ColumnDelimiter = ","
End If

Dim width As Int32 = 50
Dim DataType As wrap.DataType = wrap.DataType.DT_STR

col.ColumnType = "Delimited"
col.DataType = DataType
col.MaximumWidth = width
col.DataPrecision = 0
col.DataScale = 0
col.ColumnWidth = width
name = TryCast(col, wrap.IDTSName90)
name.Name = "Column " & cols.ToString

Next

End If

End Sub