Asp.net 必须先关闭与此连接关联的DataReader

谁能告诉我我的代码有什么问题吗？我是vb.net开发新手，因此在网上获取了一些参考代码&试图编写此代码，但出现了错误。请告诉我哪里做错了并更正我的代码

错误 已存在与此连接关联的打开的DataReader，必须先关闭该连接

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        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)
                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
                    command.CommandText = str1
                    command.Connection = con
                    adapter.SelectCommand = command
                    command.ExecuteNonQuery()
                Catch ex As Exception
                    Response.Write(ex)
                End Try

            End If
        End If
        con.Close()
    End Sub

---

所以没有人给我解决办法，我试着从我自己的角度来解决。因此，人们建议关闭data reader，但这是我的问题，因为我是一名新开发人员，所以我需要在哪里关闭data reader。在执行命令之前，我在else子句中关闭了datareader

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        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)
                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

            End If
        End If
        con.Close()
    End Sub

---

堆栈社区现在变得最糟糕。版主们很傲慢，所以没有人给我解决方案，我试着自己解决。因此，人们建议关闭data reader，但这是我的问题，因为我是一名新开发人员，所以我需要在哪里关闭data reader。在执行命令之前，我在else子句中关闭了datareader

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        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)
                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

            End If
        End If
        con.Close()
    End Sub

---

堆栈社区现在变得最糟糕。版主傲慢

您对两个嵌套命令使用相同的连接。据我所知，MySql需要两个独立的连接在同一个连接中执行任何其他SQL命令（

select*from users..，INSERT INTO users…

）之前，必须关闭DataReader。@Steve你能给出正确的答案吗please@AlexB. 请发布更正后的答案在页面右侧的“相关”面板中可以找到解决此问题的多种方法。通读一些，看看是否能找到一个有效的。两个嵌套命令使用相同的连接。据我所知，MySql需要两个独立的连接在同一个连接中执行任何其他SQL命令（

select*from users..，INSERT INTO users…

）之前，必须关闭DataReader。@Steve你能给出正确的答案吗please@AlexB. 请发布更正后的答案在页面右侧的“相关”面板中可以找到解决此问题的多种方法。通读一些，看看你是否能找到一个有效的。