我如何解决对象变量或未设置块变量 [英] how do i solve object variable or with block variable not set

问题描述

hi..am sandy.my代码是

hi..am sandy.my code is

Imports System.Data.OleDb

Partial Class Default2
    Inherits System.Web.UI.Page

    Private Property UserName As Object

    Private Property Password As Object



    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim connect As String = "Data Source=C:\Users\Administrator\Desktop\login.mdb;Provider=Microsoft.Jet.OleDb.4.0"
        Dim query As String
        query = "Select Count(*) From login Where Username = ? And Password = ?"
        Dim result As Integer = 0
        Using conn As New OleDbConnection(connect)
            Using cmd As New OleDbCommand(query, conn)
                cmd.Parameters.AddWithValue("@username", UserName.Text)
                cmd.Parameters.AddWithValue("@password", Password.Text())
                conn.Open()
                Session("Username") = UserName.Text
                result = DirectCast(cmd.ExecuteScalar(), Integer)
            End Using
        End Using
        If result > 0 Then
            Response.Redirect("default3.aspx")
        Else
            Dim label3 As String = "<script language='javascript'>alert('Invalid Username and Password')
        End If
    End Sub
End Class

i将cmd.Parameters.AddWithValue（@ username，UserName.Text）中的错误作为对象变量或使用块变量而不是set.pls帮我

i got the error at cmd.Parameters.AddWithValue("@username", UserName.Text) as object variable or with block variable not set.pls help me

推荐答案

改变这个：

Change this:

query = "Select count(*) From login Where Username = @username And Password = @password"

阅读本 SqlParameterCollection.AddWithValue方法

替换你的问题使用适当的sql参数名称标记符号...

replace your question mark symbol with the appropriate sql parameter names...

Select count(*) From login Where Username = @username And Password = @password"

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