到底哪里出错了?

Imports System.Data
Imports System.Data.OleDb

Public Class 登录
    Dim searchSQL As Object
    Public ADOcmd As OleDbDataAdapter
    Public ds As DataSet = New DataSet()
    Public mytable As Data.DataTable
    Public myrow As Data.DataRow
    Public rownumber As Integer
    Public cmd As OleDbCommandBuilder

    Public Function ExecuteSQL(ByVal SQL As String, ByVal table As String)
        ADOcmd = New OleDbDataAdapter(SQL, "Provider = Microsoft.Jet.OLEDB.4.0;Data Sourxe = D:\sql\jwxt.mdb")
        ADOcmd.Fill(ds, table)
        mytable = ds.Tables.Item(0)
        rownumber = 0
        myrow = mytable.Rows.Item(rownumber)
    End Function

    Private Sub BtOK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtOK.Click
        Dim tablename As String
        tablename = "userID"
        searchSQL = "select 用户名 , 密码 from userID where (用户名='" & txtusername.Text & " ')"
        Try
            ExecuteSQL(SearchSQL, tablename)
            If myrow.Item(1) = txtuserpassword.Text Then
                Dim newFrmmain As New frmMain()
                Me.Hide()
            Else
                Exit Sub
            End If
        Catch ex As Exception
            MsgBox("没有该用户", vbOKOnly + vbExclamation, "警告")
        End Try
    End Sub

    Private Sub txtusername_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles txtusername.Validating
        If txtusername.Text = "" Then
            ErrorProvider1.SetError(txtusername, "用户不能为空")
        Else
            ErrorProvider1.SetError(txtusername, "")
        End If
    End Sub

    Private Sub txtuserpassword_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles txtuserpassword.Validating
        If txtuserpassword.Text = "" Then
            ErrorProvider1.SetError(txtuserpassword, "密码不能为空")
        Else
            ErrorProvider1.SetError(txtuserpassword, "")

        End If
    End Sub

    Private Sub BtCancel_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BtCancel.Click
        End
    End Sub
End Class

补充：.NET技术 ,  VB.NET