Question

我不知道为什么在服务器上部署Web时出现此错误。是因为我的连接字符串的问题？请帮我。谢谢!!!

的Web.config

 <add name="Database1" connectionString="Data Source='170.21.191.85';Initial Catalog='Database1';User ID='sa';Password='123'"/>

Login.aspx.vb

Dim connection As String = System.Configuration.ConfigurationManager.ConnectionStrings("Database1").ConnectionString()
    Dim mycon As New SqlConnection(connection)

堆栈跟踪

[NullReferenceException：对象引用未设置为对象的实例。] WebApplication1.Login.ImageButton2_Click（Object sender，ImageClickEventArgs e）位于C：\ Users \ L30810 \ Desktop \ fyp final.14 \ WebApplication1 \ Login.aspx.vb：16 System.Web.UI.WebControls.ImageButton.OnClick（ImageClickEventArgs e）+86 System.Web.UI.WebControls.ImageButton.RaisePostBackEvent（String eventArgument）+115 System.Web.UI.WebControls.ImageButton.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent（String eventArgument）+7 System.Web.UI.Page.RaisePostBackEvent（IPostBackEventHandler sourceControl，String eventArgument）+11 System.Web.UI.Page.RaisePostBackEvent（NameValueCollection postData）+33 System.Web.UI.Page.ProcessRequestMain（Boolean includeStagesBeforeAsyncPoint，Boolean includeStagesAfterAsyncPoint）+1746

ImageButton2_Click

 Protected Sub ImageButton2_Click(ByVal sender As Object, ByVal e As System.Web.UI.ImageClickEventArgs) Handles ImageButton2.Click
    Dim connection As String = System.Configuration.ConfigurationManager.ConnectionStrings("Database1").ConnectionString()
    Dim mycon As New SqlConnection(connection)

    mycon.Open()

    Dim queryString As String = "SELECT Role,StaffName FROM [role] WHERE LoginID ='" + TextBox1.Text + "' and Password='" + TextBox2.Text + "'"
    Dim cmd As SqlCommand = New SqlCommand(queryString, mycon)

    Dim reader As SqlDataReader = cmd.ExecuteReader()

    Dim user1 As String = ""
    While reader.Read()
        Dim role As String = ""
        role = reader.GetString(0)
        user1 = reader.GetString(1)
        Session("role") = role
    End While

    If (Session("role") = "SA") Then
        Response.Expires = 0
        Response.ExpiresAbsolute = Now()
        Response.CacheControl = "no-cache"
        Session("User") = user1
        Response.Redirect("MainPageSA.aspx")

    ElseIf (Session("role") = "MGR") Then
        Session("User") = user1
        Response.Expires = 0
        Response.ExpiresAbsolute = Now()
        Response.CacheControl = "no-cache"
        Response.Redirect("MainPageMGR.aspx")

    ElseIf (Session("role") = "Assessor") Then
        Session("User") = user1
        Response.Expires = 0
        Response.ExpiresAbsolute = Now()
        Response.CacheControl = "no-cache"

        Response.Redirect("MainPageAssessor.aspx")

    ElseIf (Session("role") = "MC") Then
        Session("User") = user1
        Response.Expires = 0
        Response.ExpiresAbsolute = Now()
        Response.CacheControl = "no-cache"
        Response.Redirect("MainPageMC.aspx")
    Else
        MsgBox("Invalid Username/Password", MsgBoxStyle.OkOnly, "Clinical Peformance Appraisal")

    End If
    reader.Close()
    mycon.Close()
End Sub

Answer 1

您无需引用连接字符串中的值。

<add name="Database1" connectionString="Data Source=170.21.191.85;Initial Catalog=Database1;User ID=sa;Password=final"/>

你调用的对象是空的

1 个答案: