DatePicker.Clear() doesn't seem to work

[Phil]

Hi,

I'm using the RadDatePicker object for its client side functionality but not interested in the server side. I have it on a page where ViewState is switched off, being created dynamically inside a repeater.

Once a form is submitted successfully, I want the entire form cleared so that another new record can be added. However I am hitting a problem with DatePicker, DateTimePicker, and TimePicker that I cannot seem to resolve.

Here is the code I am using to create the object (there is a placeholder inside a Repeater item and this is being called at Repeater_OnItemDataBound)

private void DoDatePicker(FormColumn column, PlaceHolder ph)
        {
            var picker = new RadDatePicker {ID = column.FieldName};
            
            ph.Controls.AddAt(0, picker);
            picker.Clear();
        }

I've tried putting the picker.Clear() before and after the AddAt statement but regardless of what I set, the date from the previous form is still being displayed. I've also tried picker.SelectedDate = null, that didn't work either.

What do I need to do to clear the previous date, short of hacking into HttpContext.Current.Request and deleting all the form values connected to the Date/TimePicker?

Thanks for any assistance.

[Mira]

Hi Phil,

I suggest that you modify your code in the following way to clear the entire placeholder controls before adding the RadDatePicker:

private void DoDatePicker(FormColumn column, PlaceHolder ph)
        {
            ph.Controls.Clear();
            var picker = new RadDatePicker {ID = column.FieldName};
            ph.Controls.AddAt(0, picker);
        }

Please let me know whether it helps.

Best wishes,
Mira
the Telerik team

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[Phil]

Hi Mira

That won't work, in fact there is no way the controls can persist because ViewState has been switched off. The problem is I believe in the Request.Form variables that the DatePicker is creating. When I submit a form, the following parameters are being passed via the form:

"_rptAddForm$ctl02$dteDate"
"_rptAddForm_ctl02_dteDate_dateInput_text"
"_rptAddForm$ctl02$dteDate$dateInput"
"_rptAddForm_ctl02_dteDate_dateInput_ClientState"
"_rptAddForm_ctl02_dteDate_calendar_SD"
"_rptAddForm_ctl02_dteDate_calendar_AD"
"_rptAddForm_ctl02_dteDate_ClientState"

I understand that these variables must be necessary for the control, but I can't understand why when I clear the picker that the variables aren't overwritten with blank values. The only way I can clear these is with hacking into the Request.Form object and removing these values from the form. I'd prefer not to do it that way if there's any way I can do this using the picker.

[Mira]

Hello Phil,

I am attaching a sample project following your scenario - it is a page with ViewState disabled and on it there are a PlaceHolder, a button and a RadDatePicker inside the PlaceHolder. When the button is clicked, the following method is called

    protected void Button1_Click(object sender, EventArgs e)
    {
        var picker = new RadDatePicker { ID = "RadDatePicker1" };
        PlaceHolder1.Controls.Clear();
        PlaceHolder1.Controls.AddAt(0, picker);
    }

and the RadDatePicker is cleared properly on my side.

Please tell me is this the functionality you want or am I missing something out?

Sincerely yours,
Mira
the Telerik team

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[Phil]

Hi Mira,

I can't seem to attach files myself but I can explain how to change your file to recreate the functionality (and recreates the error as I have attempted this using your code as a base). Note that the repeater appears to be important.

First, remove the telerik.Web.UI assembly from the web.config assemblies section.

Second, this is the code for the aspx page:

<%@ Page Language="C#" AutoEventWireup="true" EnableViewState="false" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>

        <asp:ScriptManager ID="ScriptManager1" runat="server">
        </asp:ScriptManager>

        <asp:Repeater ID="_rptTest" runat="server" OnItemDataBound="TestDataBound">
            <ItemTemplate>
                <asp:PlaceHolder ID="_ph" runat="server">

                </asp:PlaceHolder>
            </ItemTemplate>
        </asp:Repeater>


        <asp:Button ID="Button1" runat="server" Text="Button" onclick="Button1_Click" />

    </div>
    </form>
</body>
</html>

Thirdly, this is the code behind file.

public partial class _Default : System.Web.UI.Page
{

    protected void Page_Load(object sender, EventArgs e)
    {
        var rptload = new int[] {1};
        _rptTest.DataSource = rptload;
        _rptTest.DataBind();
    }


    protected void Button1_Click(object sender, EventArgs e)
    {

    }

    protected void TestDataBound(object sender, RepeaterItemEventArgs e)
    {
        var ph = e.Item.FindControl("_ph");

        var picker = new RadDatePicker { ID = "RadDatePicker1" };
        picker.Clear();
        ph.Controls.Clear();

        ph.Controls.AddAt(0, picker);
    }
}

This fairly recreates the circumstance I am experiencing. Incidentally I am using Q1 2009, if Q2 2009 has got rid of this I will upgrade to that.

Thanks

Phil

[Mira]

Hi Phil,

I recommend that you set EnableViewState to true - otherwise neither RadDatePicker, nor any other control is cleared after postback - please see the attached project with a RadDatePicker and a TextBox in a Repeater's item template.

All the best,
Mira
the Telerik team

Instantly find answers to your questions on the new Telerik Support Portal.
Watch a video on how to optimize your support resource searches and check out more tips on the blogs.

[Phil]

I have to disable viewstate for the placeholder and enable for the page. Interestingly this does not happen with my bespoke user controls!

It looks like it's a weird bug with repeaters, apologies and thanks for your time.