Facebook和Google登录asp.net网站

Question

对于我的asp.net网站，我尝试了FB和Google Login的功能。 我从ASPSNIPPETS找到了教程。 现在，我所做的就是如果用户点击Facebook登录按钮，那么它首先授权用户并在面板中获取用户详细信息。 然后我把我的代码检查用户是否已经存在于我的数据库中。 如果没有，则插入用户然后输入登录代码。 我的问题是在执行第一行代码后，它会停止执行，以便无法检查用户是否已登录等等。 我认为这可能是因为重定向url会停止执行更多代码。 我该如何消除这个问题？

Protected Sub Login(sender As Object, e As EventArgs)
        FaceBookConnect.Authorize("user_photos,email", Request.Url.AbsoluteUri.Split("?"c)(0))

If Not String.IsNullOrEmpty(lblId.Text) Then
            Dim query As String = "Select ID, email From users where ID=@id"
            con.Open()
            Dim cmd As New MySqlCommand(query, con)
            cmd.Parameters.AddWithValue("@id", lblId.Text)
            Dim dr As MySqlDataReader = cmd.ExecuteReader()
            If dr.HasRows Then
                'Do Login Code here
                Try
                    Dim str As String = "select * from users where ID='" + lblId.Text + "';"
                    Dim cmd2 As New MySqlCommand(str, con)
                    Dim da As New MySqlDataAdapter(cmd2)
                    Response.Cookies("User_Type").Value = "users"
                    Response.Cookies("chkusername").Value = lblId.Text
                    Response.Redirect(Request.Url.AbsoluteUri)
                    welcome.Visible = True
                Catch ex As Exception
                    Response.Write(ex)
                End Try
            Else
                Try
                    Dim str1 As String = "INSERT INTO users (ID, DP, displayName) values('" + lblId.Text + "', '" + ProfileImage.ImageUrl.ToString + "', '" + lblName.Text + "')"
                    Dim adapter As New MySqlDataAdapter
                    Dim command As New MySqlCommand
                    dr.Close()
                    command.CommandText = str1
                    command.Connection = con
                    adapter.SelectCommand = command
                    command.ExecuteNonQuery()
                Catch ex As Exception
                    Response.Write(ex)
                End Try


                Dim con2 As New MySqlConnection("connectionstring")
                con2.Open()
                Dim cmd3 As New MySqlCommand("Select ID, email From users where ID=@id", con2)
                cmd3.Parameters.AddWithValue("@id", lblId.Text)
                Dim dr2 As MySqlDataReader = cmd3.ExecuteReader()
                If dr2.HasRows Then
                    'Do Login Code here
                    Try
                        Dim str As String = "select * from users where ID='" + lblId.Text + "';"
                        Dim cmd2 As New MySqlCommand(str, con2)
                        con2.Open()
                        Dim da As New MySqlDataAdapter(cmd3)
                        Response.Cookies("User_Type").Value = "users"
                        Response.Cookies("chkusername").Value = lblId.Text
                        Response.Redirect(Request.Url.AbsoluteUri)
                    Catch ex As Exception
                        Response.Write(ex)
                        con2.Close()
                    End Try
                    con.Close()
                End If

            End If
        End If
        con.Close()
    End Sub

Answer 1

首先，您可以优化代码：

        If Not String.IsNullOrEmpty(lblId.Text) Then
        Dim str As String = "select * from users where ID=@id"
        con.Open()
        Dim cmd2 As New MySqlCommand(str, con)
        cmd.Parameters.AddWithValue("@id", lblId.Text)
        Dim da As New Common.DataAdapter(cmd2)
        Dim ds As New Data.DataSet()
        da.Fill(ds)
        If ds.Tables(0).Rows.Count > 0 Then
            'Do Login Code here
            Try

                Response.Cookies("User_Type").Value = "users"
                Response.Cookies("chkusername").Value = lblId.Text
                Response.Redirect(Request.Url.AbsoluteUri)
                welcome.Visible = True
            Catch ex As Exception
                Response.Write(ex)
            End Try
        Else
            Try
                Dim str1 As String = "INSERT INTO users (ID, DP, displayName) values(@id, @img,@name)"
                Dim cmd As New MySqlCommand
                cmd = New SqlCommand(req, con)
                cmd.Parameters.Add(New SqlParameter("@id", lblId.Text))
                cmd.Parameters.Add(New SqlParameter("@img", ProfileImage.ImageUrl.ToString))
                cmd.Parameters.Add(New SqlParameter("@name", lblName.Text))
                cmd.ExecuteNonQuery()
            Catch ex As Exception
                Response.Write(ex)
            End Try
            'After insertion you don't have to select  from database just send the parameters to cookies
            Response.Cookies("User_Type").Value = "users"
            Response.Cookies("chkusername").Value = lblId.Text
            Response.Redirect(Request.Url.AbsoluteUri)

        End If
        con.Close()
    End If