Configuring a SharePoint WebPart as both a Consumer and Provider for the same interface

Recently I’ve been coding a web part that shows a sql query inside a SPGridView and wanted to set it up so it could be a connection provider (ConnectionProvider) as well as a connection consumer (ConnectionConsumer).

For some reason, when I set it up this way the Connections menu used to configure the inbound and outbound connections was greyed out when I had both, but worked if I commented out either one.

It seems that there is an optional argument named “id” for both the ConnectionProvider and ConnectionConsumer decorators and when I provided this argument it started working. It seems there is a default id if you don’t specify it and they must have the same default id.

My code now looks something like this:

#Region "IWebPartRow Provider"
        <ConnectionProvider("RowProvider", "DataViewRowProvider")> _
        Public Function GetConnectionInterface() As IWebPartRow
            Return New DataViewWebPart()
        End Function

        Public Sub GetRowData(ByVal callback As RowCallback) _
              Implements IWebPartRow.GetRowData
            callback(oGrid.SelectedRow)

        End Sub

        Public ReadOnly Property Schema() As  _
  ComponentModel.PropertyDescriptorCollection Implements IWebPartRow.Schema
            Get
                Return TypeDescriptor.GetProperties(oView)
            End Get
        End Property
#End Region
#Region "IWebPartRow Consumer"
        <ConnectionConsumer("Row", "DataViewRowConsumer")> _
        Public Sub SetConnectionInterface(ByVal provider As IWebPartRow)
            _provider = provider
        End Sub

#End Region