mysqldatareader生成时出错

我在vb.net中有一个函数,它在启动主应用程序之前对用户的mysql数据库进行身份验证。功能代码如下:

    Public Function authConnect() As Boolean
    Dim dbserver As String
    Dim dbuser As String
    Dim dbpass As String
    dbserver = My.Settings.dbserver.ToString
    dbuser = My.Settings.dbuser.ToString
    dbpass = My.Settings.dbpass.ToString
    conn = New MySqlConnection
    myConnString = "server=" & dbserver & ";" & "user id=" & dbuser & ";" & "password=" & dbpass & ";" & "database=rtadmin"
    Dim myCommand As New MySqlCommand
    Dim myAdapter As New MySqlDataAdapter
    Dim myData As New DataTable
    Dim myDataReader As New MySqlDataReader
    Dim query As String

    myCommand.Parameters.Add(New MySqlParameter("?Username", login_usr_txt.Text))
    myCommand.Parameters.Add(New MySqlParameter("?Password", login_pass_txt.Text))
    query = "select * from users where user = ?Username and passwd = ?Password"
    conn.ConnectionString = myConnString
    Try
        conn.Open()
        Try
            myCommand.Connection = conn
            myCommand.CommandText = query
            myAdapter.SelectCommand = myCommand
            myDataReader = myCommand.ExecuteReader
            If myDataReader.HasRows() Then
                MessageBox.Show("You've been logged in.", "RT Live! Information", MessageBoxButtons.OK, MessageBoxIcon.Information)
            End If
        Catch ex As Exception

        End Try
    Catch ex As Exception

    End Try
End Function    

函数还没有完成,在启动应用程序之前还需要做一些其他的事情,因为我正在使用一个消息框来显示登录尝试的结果。

我得到的错误如下:

错误1“mysql.data.mysqlclient.mysqldatareader.friend sub new(cmd为mysql.data.mysqlclient.mysqlcommand,statement为mysql.data.mysqlclient.preparablestatement,behavior为system.data.commandbehavior)”在此上下文中不可访问,因为它是“friend”。C:\Users\Mario\Documents\Visual Studio 2010\Projects\Remote Techs Live!\远程技术现场!\ login.vb 43 13远程技术现场!

有什么想法吗?