MySqlDataReader 在构建时给出错误

Question

我在 VB.NET 中有一个函数，可以在启动主应用程序之前对 MySQL 数据库的用户进行身份验证。这是函数的代码:

    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    

该功能尚未完成，在启动应用程序之前还需要做一些其他事情，因为我正在使用 MessageBox 来显示登录尝试的结果。

我得到的错误如下:

Error 1 'MySql.Data.MySqlClient.MySqlDataReader.Friend Sub New(cmd As MySql.Data.MySqlClient.MySqlCommand, statement As MySql.Data.MySqlClient.PreparableStatement, behavior As System.Data.CommandBehavior)' is not accessible in this context because it is 'Friend'. C:\Users\Mario\documents\visual studio 2010\Projects\Remote Techs Live!\Remote Techs Live!\Login.vb 43 13 Remote Techs Live!

有什么想法吗？

Answer 1

尝试创建一个 MySqlDataReader 然后将其丢弃是没有意义的!

首先，您这样做是为了尝试创建一个阅读器:

    Dim myDataReader As New MySqlDataReader

然后当你这样做的时候，你会试图把它扔掉:

    myDataReader = myCommand.ExecuteReader

只需从您的初始声明中删除 New 即可。我怀疑 MySqlDataReader 的构造函数不可公开访问。