'Connection' is not a member of 'System.Data.SqlClient.SqlDataAda

Hej Eksperter
Jeg er ny indenfor .net, så den her er sikkert ganske simpel.
Jeg er ved at lave en login side.

Jeg får den her fejlmeddelese

BC30456: 'Connection' is not a member of 'System.Data.SqlClient.SqlDataAdapter'.

i den her linie

MyCommand.Connection.Open()

her er min kode

<script runat="server">

    Sub Click(Obj as Object, e as Imageclickeventargs)

        Dim connectionString As String = "server='xxx'; user id='xxxx'; password='xxxxx'; database='xxxxx'"
        Dim dbConnection As System.Data.IDbConnection = New System.Data.SqlClient.SqlConnection(connectionString)
        Dim DS As New DataSet
        Dim reader as string

        Dim MyConnection as New SqlConnection(connectionString)
        Dim MyCommand As New SqlDataAdapter("select * from netsiteusers where (username='" & username.Text & "') and (password='" & password.Text & "')" , MyConnection)
        MyCommand.Connection.Open()

        reader = myCommand.ExecuteNonQuery()

        MyCommand.Close()
        if reader > "" then
            Message.Text = "<br>Du er logget ind"
        Else
            Message.Text = "<br>Fejl i brugernavn eller password. Prøv igen"
        End If
    End Sub

</script>
<%@ Import Namespace="System" %>
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Data.SqlClient" %>


Hvad går der galt.