Do postBack when the RadComboBox has closed in UI for ASP.NET AJAX

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Do postBack when the RadComboBox has closed

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ComboBox

This is a migrated thread and some comments may be shown as answers.

9 Answers, 1 is accepted

answered on 04 Apr 2008, 05:10 PM

Hello JUAN CRESPO,

One option would be to do a callback from the OnClientDropDownClosing event handler by using the RadAjaxManger functionality (more information on the approach here). This way you could avoid the actual postback.

On the other hand, if you wish to do a postback after the drop down has closed, you could use another approach: create an invisible asp Button which has its OnClick event handler on the server; hook to the OnClientDropDownClosed client event of the RadComboBox control and call the afore-mentioned button's click function, which will trigger the server-side event.

I hope this information is useful.

Sincerely yours,
Simon
the Telerik team

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Accepted

answered on 09 Apr 2008, 12:06 PM

RadComboBoxOnDropDownCloseServerEvent.zip

Hello JUAN CRESPO,

I suggest that you try the second approach: use a specific helper button which will do a postback on the server when a specific RadComboBox's DropDown closes.

The main advantage of this approach is that you could use different buttons for different RadComboBoxes which will ensure that you know on the server which RadComboBox's DropDown has closed.

Please find attached a sample project which illustrates the described above. Please download it and give it a go.

I hope it meets your requirements.

All the best,
Simon
the Telerik team

Instantly find answers to your questions at the new Telerik Support Center

answered on 29 Jul 2009, 09:44 PM

Hello,

I'm trying to achieve the following: if the selection of the drop down has not changed, do not postBack. if the selection has changed, do postBack. How would I achieve this? I tried to change OnClientDropDownClosing to OnClientSelectedIndexChanged but the OnClientSelectedIndexChanged event was not fired.

I'm using version 2009.2.701.35. My sample code is as below. Thanks for your help!

    
            <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %> 
        
            <%@ Register Assembly="Telerik.Web.UI" Namespace="Telerik.Web.UI" TagPrefix="telerik" %> 
        
            <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> 
        
            <html xmlns="http://www.w3.org/1999/xhtml">  
        
            <head runat="server">  
        
                <title>Untitled Page</title> 
        
                <style type="text/css">  
        
                    .Hidden  
        
                    {  
        
                        visibility: hidden;  
        
                    }  
        
                </style> 
        
            </head> 
        
            <body> 
        
                <script type="text/javascript">  
        
                function checkboxClick(e)    
        
                   {    
        
                        e.cancelBubble = true;    
        
                        if (e.stopPropagation)    
        
                        {    
        
                            e.stopPropagation();    
        
                        }    
        
                    }    
        
                    function OnClientDropDownClosing(sender)  
        
                    {  
        
                       document.getElementById(sender.get_id() + "Helper").click();  
        
                    }  
        
                </script> 
        
                <form id="form1" runat="server">  
        
                <asp:ScriptManager ID="ScriptManager1" runat="server" /> 
        
                <div> 
        
                    <telerik:RadComboBox runat="server" ID="RadComboBox1" Height="200" HighlightTemplatedItems="true" 
        
                        AutoPostBack="false" AllowCustomText="true" Text="All">  
        
                        <Items> 
        
                            <telerik:RadComboBoxItem Text="One" /> 
        
                            <telerik:RadComboBoxItem Text="Two" /> 
        
                            <telerik:RadComboBoxItem Text="Three" /> 
        
                        </Items> 
        
                        <ItemTemplate> 
        
                            <div> 
        
                                <asp:CheckBox onclick="checkboxClick(event);" runat="server" ID="CheckBox" Text="" /> 
        
                                <%# DataBinder.Eval(Container, "Text") %> 
        
                            </div> 
        
                        </ItemTemplate> 
        
                    </telerik:RadComboBox> 
        
                    <asp:Button ID="RadComboBox1Helper" runat="server" Text="" CssClass="Hidden" OnClick="ButtonHelper_Click" /> 
        
                </div> 
        
                </form> 
        
            </body> 
        
            </html>

    
            using System;  
        
            using System.Web.UI;  
        
            public partial class _Default : System.Web.UI.Page  
        
            {  
        
                protected void Page_Load(object sender, EventArgs e)  
        
                {  
        
                    if (!IsPostBack)  
        
                    {  
        
                        RadComboBox1.DataBind();  
        
                        RadComboBox1.OnClientDropDownClosing = "OnClientDropDownClosing";  
        
                        //RadComboBox1.OnClientSelectedIndexChanging = "OnClientDropDownClosing";  
        
                    }  
        
                    Page.Title = "new title";  
        
                } 
        
                #region DropDown Closed Events  
        
                protected void ButtonHelper_Click(object sender, EventArgs e)  
        
                {  
        
                    RadComboBox1.Text = "13";  
        
                } 
        
                #endregion  
        
            }

Thanks,
Ashley

answered on 17 Sep 2014, 07:32 PM

Hi,
I tried this and is not working fine and no errors.
If I open the box and I select something and close, nothing. The button doesn't work.
After that I open and I close without touch anything and voila... the button works!
I had to add the code ClientIDMode="Static" because without this, doesn't work...
I'm using the new Telerik 2014.
We have the old one and no problem, but with the new Telerik UI AJAX is not working fine...

Any suggestions?

Thanks

function OnClientDropDownClosing(sender) {
            document.getElementById(sender.get_id() + "Helper").click();
        }

<telerik:RadComboBox ID="rcbProdGroup" runat="server" AutoPostBack="true" ClientIDMode="Static"
                        EmptyMessage="-All-" CheckBoxes="true" OnClientDropDownClosing="OnClientDropDownClosing"
                         DropDownAutoWidth="Enabled" EnableVirtualScrolling="true" >
                    </telerik:RadComboBox>
                    <asp:Button ID="rcbProdGroupHelper" runat="server" onclick="rcbProdGroupHelper_Click" ClientIDMode="Static"
                       Text="Get Item Ids" />