Question

I need some help with correctly implementing the USING statement with strongly typed TableAdapters

I have something like this:

Using myDT As New mbr_Account.mbr_AccountDataTable
     Using myTA As New mbr_AccountTableAdapters.mbr_AccountTableAdapter
           myTA.Connection.Open()
           myTA.Fill(myDT)
           myTA.Connection.Close()
     End Using

     For Each row In myDT
          'do stuff
     Next
End Using

This would correctly dispose of the datatable and tableadapter but does not address the issue of the connection object.

How should I dispose the Connection object?

I could wrap the connection in a Try… Finally like this:

Using myDT As New mbr_Account.mbr_AccountDataTable
    Using myTA As New mbr_AccountTableAdapters.mbr_AccountTableAdapter
        Try
            myTA.Connection.Open()
            myTA.Fill(myDT)
        Finally
            If Not IsNothing(myTA.Connection) Then
                myTA.Connection.Close()
                myTA.Connection.Dispose()
            End If
        End Try
    End Using

    For Each row In myDT
        'do stuff
    Next
End Using

Question : How can I use the USING keyword instead of Try.. Finally for the connection object?

Answer 1

I have just found out that TableAdapters handle opening and closing of connections automatically and there is no need to manually add the code.

Basically, they already contain Try … Finally blocks to handle closing of connections during exceptions.

The Designer generated Insert/Delete/Update code looks like this:

global::System.Data.ConnectionState previousConnectionState = this.Adapter.InsertCommand.Connection.State;
    if (((this.Adapter.InsertCommand.Connection.State & global::System.Data.ConnectionState.Open) 
                != global::System.Data.ConnectionState.Open)) {
        this.Adapter.InsertCommand.Connection.Open();
    }
    try {
        int returnValue = this.Adapter.InsertCommand.ExecuteNonQuery();
        return returnValue;
    }
    finally {
        if ((previousConnectionState == global::System.Data.ConnectionState.Closed)) {
            this.Adapter.InsertCommand.Connection.Close();
        }
    }

Therefore no need to close or dispose the connection object.