Validation of dinamically created checkbox

Question

User1877874361 posted

Hello, 

I've populated a checkbox list dynamically from a database . before submit my form I want to validate at least one checkbox checked for each group. For this I'm using Custom field Validatos both Requiered Field Validator but it doesn't work on submit.

The code I'm using is as follows:

  Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
...................

                            Dim n As Integer = 0
                            Do While sdr02.Read
                                n = n + 1
                                '1º.- creamos objeto checkbox
                                ' Panel3.Controls.Add(New LiteralControl("  "))
                                Dim chkpregunta As New CheckBoxList
                                chkpregunta.ID = sdr02(0) + n
                                chkpregunta.Items.Add(Trim(sdr02(2)))
                                Panel3.Controls.Add(chkpregunta)

                            Loop
                            'validación
                            Dim chkValidator As New RequiredFieldValidator
                            chkValidator.ControlToValidate = chkpregunta
                            chkValidator.ErrorMessage = "Debes de seleccionar al menos una opción para " + Trim(sdr02(2))
                            chkValidator.ValidationGroup = "chkPreguntas"
                            chkValidator.ID = vectorId(0) & "--" & sdr02(0)
                            chkValidator.SetFocusOnError = True
                            Panel3.Controls.Add(chkValidator)
                            'validación fin


                        Catch ex As Exception

                        End Try
                       .........................................

    End Sub

If someone could give me an orientation of what I'm doing wrong it will be much appreciated

thanks

Answer 1

User475983607 posted

If someone could give me an orientation of what I'm doing wrong it will be much appreciated

Dynamic controls must be recreated early in the page life cycle, otherwise the framework has no idea the controls exist when page state is stood up.  This particular question is ask often over many years and there is a lot of information about creating dynamic controls that a simple Internet search will turn up.

I recommend that you use standard Web Forms patterns and rather than creating checkboxes use a data bound control like a checkbox.

IF you must use dynamic controls then yo must write code to recreate the controls on the Page_Init or Page_load events.

Answer 2

User1877874361 posted

thanks for answering Mgebhard,

I'll give a round at all.

best regards

Answer 3

User-1171043462 posted

If you want dynamic CheckBoxes from Database go for a CheckBoxList control

Bind CheckBoxList from Database in ASP.Net - ASPSnippets

And for At Least one checked refer

Validate ASP.Net CheckBoxList (at least one CheckBox checked ...

Answer 4

User1877874361 posted

Hi Mudassar, thanks for your answer.

Your code is always pretty fine, but in this case I don't know the exactly number of checkboxes as the user choose previously the options, so the number of checkboxes to validate is always variable.

that is the reason to create them in code behind. In a previous webform user can choose a number of options from a listbox. After this, I show him a number of options based on this selection.

For your clarity the code for the first webform is as follows:

 <asp:listbox ID="ddlcompetencias" runat="server" DataSourceID="SqlDataSource3"  SelectionMode ="Multiple"
               DataTextField="Competencia" DataValueField = "KeyComp" AppendDataBoundItems = "true" Height="224px" Width="244px" CssClass="NormalBold">
                                    
                    </asp:listbox>

    <asp:RequiredFieldValidator ID="rfvCompetencias" ControlToValidate="ddlcompetencias" InitialValue="" 
        runat="server" ErrorMessage="al menos una competencia obligatorio" ValidationGroup="excPlantilla"></asp:RequiredFieldValidator>



     <asp:SqlDataSource ID="SqlDataSource3" runat="server" ConnectionString="<%$ ConnectionStrings:oConn %>"
                        SelectCommand="usp_Competencias_SELECT" SelectCommandType ="StoredProcedure">
                    </asp:SqlDataSource>

user choose one or more options from this Listbox. Once the form has been submitted, I bind a template from previous options from a database where I show user possible options for each one oh the previous selected.

The complete code in this case is as follows: (I cannot insert a screenshot in this space, sorry)

  Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        lblNT.Text = Session("nt")
        lblOficina.Text = Request.Form("ddlOficina")
            lblCliente.Text = Request.Form("ddlclientes")
            lblPuesto.Text = Request.Form("ddlPuesto")
            lblFecha.Text = DateTime.Now
            'carga de campos ocultos
            hidecliente.Value = lblCliente.Text
            hident.Value = lblNT.Text
            hidepuesto.Value = lblPuesto.Text
            hideOficina.Value = lblOficina.Text



            'desglosamos competencias con coma
            Dim vectorComp = Split(Request.Form("ddlCompetencias"), ",")

            'separamos la competencia de su id
            For i = 0 To UBound(vectorComp) 'RECORREMOS EL VECTOR
                Dim vectorId = Split(vectorComp(i), "-")





                'Consulta para capturar la descripción de cada Competencia
                Dim Conn1 As New SqlConnection
                Conn1.ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings("oConn").ConnectionString
                Dim cmd01 As SqlCommand = New SqlCommand
                cmd01.CommandText = "usp_Competencias_GET"
                cmd01.CommandType = CommandType.StoredProcedure
                cmd01.Connection = Conn1
                Conn1.Open()
                cmd01.Parameters.Add("@pIdComp", SqlDbType.Int).Value = vectorId(0)
                Dim sdr01 As SqlDataReader = cmd01.ExecuteReader
                Try


                    Do While sdr01.Read
                        'etiqueta nombre competencia
                        Dim lblCompetencia As New Label
                        lblCompetencia.Text = vectorId(1)
                        lblCompetencia.ID = vectorId(0)
                        lblCompetencia.CssClass = "NormalBold"
                        Panel3.Controls.Add(lblCompetencia)


                        Panel3.Controls.Add(New LiteralControl("<br />"))
                        Panel3.Controls.Add(New LiteralControl("<hr />"))
                        'etiqueta descripción competencia
                        Dim lblCompetenciaDesc As New Label
                        Dim lbltextodesc As New Label
                        lbltextodesc.Text = "Descripción :"
                        Panel3.Controls.Add(lbltextodesc)
                        lblCompetenciaDesc.Text = sdr01(0)
                        lblCompetenciaDesc.CssClass = "normalbold"
                        Panel3.Controls.Add(lblCompetenciaDesc)
                        Panel3.Controls.Add(New LiteralControl("<br />"))
                        Panel3.Controls.Add(New LiteralControl("<br />"))
                        Panel3.Controls.Add(New LiteralControl("<br />"))

                        '*****************************************************
                        'agregamos opciones de pregunta para cada competencia
                        '*****************************************************
                        'campo clave de búsqueda = vectorid(0) anterior
                        Dim Conn2 As New SqlConnection
                        Conn2.ConnectionString = System.Configuration.ConfigurationManager.ConnectionStrings("oConn").ConnectionString
                        Dim cmd02 As SqlCommand = New SqlCommand
                        cmd02.CommandText = "usp_Preguntas_x_Comp_GET"
                        cmd02.Parameters.Add("@pIdComp", SqlDbType.Int).Value = vectorId(0)
                        cmd02.CommandType = CommandType.StoredProcedure
                        cmd02.Connection = Conn2
                        Conn2.Open()
                        Dim sdr02 As SqlDataReader = cmd02.ExecuteReader

                        Try


                            Dim n As Integer = 0
                            Do While sdr02.Read
                                n = n + 1
                                '1º.- creamos objeto checkbox
                                ' Panel3.Controls.Add(New LiteralControl("&nbsp;&nbsp;"))
                                Dim chkpregunta As New CheckBoxList
                            chkpregunta.ID = Convert.ToInt16(sdr02(0)) + Convert.ToInt16(n)
                            chkpregunta.Items.Add(Trim(sdr02(2)) + "**")
                            Panel3.Controls.Add(chkpregunta)

                        Loop



                    Catch ex As Exception

                        End Try
                        '*****************************************************
                        'fin opciones de pregunta para cada competencia
                        '*****************************************************
                    Loop







            Catch ex As Exception

                End Try
                Panel3.Controls.Add(New LiteralControl("<br />"))

            Next

            'Fin consulta captura descripción competencia

            Panel3.Controls.Add(New LiteralControl("<br />"))
            Panel3.Controls.Add(New LiteralControl("<br />"))
            Dim cmdGrabarExC As New Button
            cmdGrabarExC.PostBackUrl = "~/ViewTemplateExC.aspx"
            cmdGrabarExC.ID = "cmdgrabarexc"
            cmdGrabarExC.CssClass = "CommandButton"
            cmdGrabarExC.ValidationGroup = "chkPreguntas"
            cmdGrabarExC.Text = "Grabar plantilla"
            Panel3.Controls.Add(cmdGrabarExC)





    End Sub

The par of code in Bold is the one I need to validate to ensure at least one option for each group is selected.

example:

option selected one

checkbox option selected one + description

checkbox option selected two + description

checkbox option selected three + description

checkbox option selected four + description

Option selected Two

checkbox option selected one + description

checkbox option selected two + description

checkbox option selected three + description

Option selected three

checkbox option selected one + description

checkbox option selected two + description

checkbox option selected three + description

.......................................

Please, let me know if this explanation is clear enough

thanks for your time

Answer 5

User-1171043462 posted

I don't know the exactly number of checkboxes as the user choose previously the options, so the number of checkboxes to validate is always variable.

For CheckBoxList also you don't need to know. It can populate any no of CheckBoxes.

Also my Validation program will validate any number of CheckBoxes.

Answer 6

User1877874361 posted

In this sense, how can I call my ID field to validate from your script?

    <script type="text/javascript">
    function ValidateCheckBoxList(sender, args) {
        var checkBoxList = document.getElementById("<%=chkpregunta.id %>");
        var checkboxes = checkBoxList.getElementsByTagName("input");
        var isValid = false;
        for (var i = 0; i < checkboxes.length; i++) {
            if (checkboxes[i].checked) {
                isValid = true;
                break;
            }
        }
        args.IsValid = isValid;
    }
</script>


</head>
<body>

following your code I'llcreate  dynamically a CustomValidator for each group ...

 Dim n As Integer = 0
                            Do While sdr02.Read
                                n = n + 1
                                '1º.- creamos objeto checkbox
                                ' Panel3.Controls.Add(New LiteralControl("  "))
                                Dim chkpregunta As New CheckBoxList
                            chkpregunta.ID = Convert.ToInt16(sdr02(0)) + Convert.ToInt16(n)
                            chkpregunta.Items.Add(Trim(sdr02(2)) + "**")
                            Panel3.Controls.Add(chkpregunta)

                        Loop

                        Dim chkvalidator As New CustomValidator
                        chkvalidator.ID = Convert.ToInt16(n)
                        chkvalidator.ErrorMessage = "Al menos una opción"
                        chkvalidator.ClientValidationFunction = "ValidateCheckBoxList"

can I replace directly  chkfruits.clientID with chkpregunta.ID, or no???

thanks!!

Answer 7

User475983607 posted

Use a class selector on the checkbox container.

Still unclear why you can't use standard data bound controls as it looks like you are just looping over a collection to create the checkboxes. 

Answer 8

User-1171043462 posted

Why you need to create a Dynamic Validator and dynamic CheckBoxList?

Just pass data from database to CheckBoxList and it will generate CheckBoxes

Answer 9

User475983607 posted

I agree with mudassarkhan.  It seems like you are making the design more complicated than needed.

Answer 10

User1877874361 posted

I need to create dynamic checkboxes because not all records had the same information, if recordset returns a different number of records each time I cannot generate a static number of checkboxes.

in first webform, user can select a no spscific number of categories from a Listbox Object. In current webform, for each category, data source read the options availables for each category.

in example, first user can select two categories , but next user can select five or more. In each case the system will create a template for each group of categories selected so you will see available options in a checkbox list for each one.

Answer 11

User475983607 posted

I don't get it.  The code shown is looping over a collection and creating server controls manually.  Rather than manually rendering server controls, simply assign the data source to the data bound control. 

Users are isolated from one another in web applications.  Can you explain why the number of users and each user selection can affect the other users and how this dictates that the controls must be created manually?  It just does not make sense.

Answer 12

User1877874361 posted

I am going to think about your words, this is the consequence of my own inexperience and then you are both right.

I am making a longer and more complex waywhen in reality it could be simpler.

Thank you very much for your support and cordial greetings

Answer 13

User-1171043462 posted

Just one thing from my experience. Simpler applications are easier to maintain, find bugs and also change in future.

Answer 14

User1877874361 posted

ok, thanks both for your time

;)