使用if else语句更新mysql中的插入列值并尝试catch语句

Question

我想出了if else语句处理多个try catch语句的代码。它在第一个if语句中工作，但在else if语句中它已经不起作用了。 你能帮助我吗？？？ 这是代码

    If cmbxyear.Text = "NURSERY" Then

        MySqlConnection = New MySqlConnection
        MySqlConnection.ConnectionString = "server = localhost; port=3307; user id = root; password = 1234; database = mcs;"
        Dim READER As MySqlDataReader
        lblyear.Text = "N"

        Try


            MySqlConnection.Open()
            Dim query As String
            query = " insert into mcs.nursery (last_name, first_name, middle_name, year_grade, school_year) Values ('" & txtlastname.Text & "','" & txtfirstname.Text & "','" & txtmiddlename.Text & "','" & cmbxyear.Text & "','" & cmbxschoolyear.Text & "') "
            Dim Command As New MySqlCommand(query, MySqlConnection)
            READER = Command.ExecuteReader

            MessageBox.Show("Student Successfully Registered")
            MySqlConnection.Close()

        Catch ex As Exception
            MessageBox.Show(ex.Message)
        Finally
            MySqlConnection.Dispose()

        End Try

        Try
            MySqlConnection.Open()
            Dim query As String
            query = " select id from mcs.nursery where last_name = '" & txtlastname.Text & "' and first_name = '" & txtfirstname.Text & "' and middle_name = '" & txtmiddlename.Text & "'"
            Dim Command As New MySqlCommand(query, MySqlConnection)
            READER = Command.ExecuteReader
            READER.Read()
            lblno.Text = READER(0)


            MessageBox.Show("Student Number Generated")
            MySqlConnection.Close()


            Dim lbl1 As String = lblyear.Text
            Dim lbl2 As String = lblno.Text

            lblstudentno.Text = (String.Concat(lblyear.Text, "-", lblno.Text))

        Catch ex As Exception
            MessageBox.Show(ex.Message)
        Finally
            MySqlConnection.Dispose()

        End Try

        Try
            MySqlConnection.Open()

            Dim query2 As String
            query2 = "update mcs.nursery set student_no = '" & lblstudentno.Text & "' where last_name = '" & txtlastname.Text & "'and first_name = '" & txtfirstname.Text & "' and middle_name = '" & txtmiddlename.Text & "' "
            Dim Command As New MySqlCommand(query2, MySqlConnection)
            READER = Command.ExecuteReader

            MySqlConnection.Close()

        Catch ex As Exception
            MessageBox.Show(ex.Message)
        Finally
            MySqlConnection.Dispose()

        End Try



    ElseIf cmbxyear.Text = "KINDER ONE" Then
        MySqlConnection = New MySqlConnection
        MySqlConnection.ConnectionString = "server = localhost; port=3307; user id = root; password = 1234; database = mcs;"
        Dim READER As MySqlDataReader

        lblyear.Text = "K1"

        Try

            MySqlConnection.Open()
            Dim query As String
            query = " insert into mcs.kinder_one (last_name, first_name, middle_name, year_grade, school_year) Values ('" & txtlastname.Text & "','" & txtfirstname.Text & "','" & txtmiddlename.Text & "','" & cmbxyear.Text & "','" & cmbxschoolyear.Text & "') "
            Dim Command As New MySqlCommand(query, MySqlConnection)
            READER = Command.ExecuteReader

            MessageBox.Show("Student Successfully Registered")
            MySqlConnection.Close()

        Catch ex As Exception
            MessageBox.Show(ex.Message)
        Finally
            MySqlConnection.Dispose()

        End Try

        Try
            MySqlConnection.Open()
            Dim query As String
            query = " select id from mcs.kinder_one where last_name = '" & txtlastname.Text & "' and first_name = '" & txtfirstname.Text & "' and middle_name = '" & txtmiddlename.Text & "'"
            Dim Command As New MySqlCommand(query, MySqlConnection)
            READER = Command.ExecuteReader
            READER.Read()
            lblno.Text = READER(0)


            MessageBox.Show("Student Number Generated")
            MySqlConnection.Close()


            Dim lbl1 As String = lblyear.Text
            Dim lbl2 As String = lblno.Text

            lblstudentno.Text = (String.Concat(lblyear.Text, "-", lblno.Text))

        Catch ex As Exception
            MessageBox.Show(ex.Message)
        Finally
            MySqlConnection.Dispose()

        End Try

        Try
            MySqlConnection.Open()

            Dim query2 As String
            query2 = "update mcs.kinder_one set student_no = '" & lblstudentno.Text & "' where last_name = '" & txtlastname.Text & "'and first_name = '" & txtfirstname.Text & "' and middle_name = '" & txtmiddlename.Text & "' "
            Dim Command As New MySqlCommand(query2, MySqlConnection)
            READER = Command.ExecuteReader

            MySqlConnection.Close()

        Catch ex As Exception
            MessageBox.Show(ex.Message)
        Finally
            MySqlConnection.Dispose()

        End Try



    ElseIf cmbxyear.Text = "KINDER TWO" Then
        MySqlConnection = New MySqlConnection
        MySqlConnection.ConnectionString = "server = localhost; port=3307; user id = root; password = 1234; database = mcs;"
        Dim READER As MySqlDataReader

        lblyear.Text = "K2"

        Try
            MySqlConnection.Open()
            Dim query As String
            query = " insert into mcs.kinder_two (last_name, first_name, middle_name, year_grade, school_year) Values ('" & txtlastname.Text & "','" & txtfirstname.Text & "','" & txtmiddlename.Text & "','" & cmbxyear.Text & "','" & cmbxschoolyear.Text & "') "
            Dim Command As New MySqlCommand(query, MySqlConnection)
            READER = Command.ExecuteReader

            MessageBox.Show("Student Successfully Registered")
            MySqlConnection.Close()

        Catch ex As Exception
            MessageBox.Show(ex.Message)
        Finally
            MySqlConnection.Dispose()

        End Try

        Try
            MySqlConnection.Open()
            Dim query As String
            query = " select id from mcs.kinder_two where last_name = '" & txtlastname.Text & "' and first_name = '" & txtfirstname.Text & "' and middle_name = '" & txtmiddlename.Text & "'"
            Dim Command As New MySqlCommand(query, MySqlConnection)
            READER = Command.ExecuteReader
            READER.Read()
            lblno.Text = READER(0)


            MessageBox.Show("Student Number Generated")
            MySqlConnection.Close()


            Dim lbl1 As String = lblyear.Text
            Dim lbl2 As String = lblno.Text

            lblstudentno.Text = (String.Concat(lblyear.Text, "-", lblno.Text))

        Catch ex As Exception
            MessageBox.Show(ex.Message)
        Finally
            MySqlConnection.Dispose()

        End Try

        Try
            MySqlConnection.Open()

            Dim query2 As String
            query2 = "update mcs.kinder_two set student_no = '" & lblstudentno.Text & "' where last_name = '" & txtlastname.Text & "'and first_name = '" & txtfirstname.Text & "' and middle_name = '" & txtmiddlename.Text & "' "
            Dim Command As New MySqlCommand(query2, MySqlConnection)
            READER = Command.ExecuteReader

            MySqlConnection.Close()

        Catch ex As Exception
            MessageBox.Show(ex.Message)
        Finally
            MySqlConnection.Dispose()

        End Try