我将如何在vb.net中将sql查询设置为变量

Question

    Private Sub btncalc_Click(Sender,e)
    a = val(txtConcode.Text)
    b = val(txtConsumed.Text)
    If a = 1 Then
    Dim cmd as new mysqlcommand
    cmd.connection = con
    connect()
    cmd.CommandText = "select Rate from tblrate where ConvertID=1"
    dr = cmd.ExecuteReader
    if dr.Read Then
    q = dr.Read
    end if
    disconnect()

我想知道的是，我怎么能从我的SQL查询中获取值 并将其转移到变量q 我刚刚创建了dr的东西，例如