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[Solved] Load on demand example - how to display multi-cols?

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ComboBox

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

Jon asked on 21 Feb 2008, 06:51 PM

How do display multiple columns in the load by demand example?
The following code from the multi-col does not display the data.
Do I have to bind the datatable to the combox for this to work.
It seems the databinding to the radcombo takes a while.. thanks in advance.

HeaderTemplate>

<tr>

Company Name

</td>

City

</td>

Title

</td>

</tr>

</table>

</HeaderTemplate>

<tr>

# DataBinder.Eval(Container.DataItem, "CompanyName") %>

</td>

# DataBinder.Eval(Container.DataItem, "City") %>

</td>

# DataBinder.Eval(Container.DataItem, "ContactTitle") %>

</td>

</tr>

</table>

</ItemTemplate>

17 Answers, 1 is accepted

answered on 25 Feb 2008, 04:33 PM

Hi Jon Elster,

You can add items at runtime in the ItemsRequested event of RadComboBox without using databindings.

For an example:

    
               Protected Sub RadComboBox1_ItemsRequested(ByVal sender As Object, ByVal e As RadComboBoxItemsRequestedEventArgs)  
        
                                  RadComboBox1.Items.Add(new RadComboBoxItem("text", "value")    
        
                  End Sub

Hope this helps.

Kind regards,
Rosi
the Telerik team

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answered on 09 Mar 2009, 01:46 PM

Thanks for your response :)

That example, unfortunately, does *not* show an on load demand with multi columns

This is your demo code below. In the *demo* code you do not see the following three lines. They are not there.

ShowMoreResultsBox="true"
EnableLoadOnDemand="true"
EnableVirtualScrolling = "true"

in its definition.

Demo code combo definition.

    
            <telerik:RadComboBox  
        
                                runat="server" ID="RadComboBox1"   
        
                             Height="190px" Width="420px"   
        
                             Skin="Vista" 
        
                                MarkFirstMatch="true"   
        
                                DataSourceID="SessionDataSource1"   
        
                                EnableLoadOnDemand="true"   
        
                                HighlightTemplatedItems="true" 
        
                                OnClientItemsRequested="UpdateItemCountField"   
        
                                OnDataBound="RadComboBox1_DataBound"   
        
                                OnItemDataBound="RadComboBox1_ItemDataBound" 
        
                                OnItemsRequested="RadComboBox1_ItemsRequested">  
        
                                <HeaderTemplate> 
        
                                    <ul> 
        
                                     <li class="col1">Contact Name</li> 
        
                                     <li class="col2">City</li> 
        
                                     <li class="col3">Title</li> 
        
                                    </ul> 
        
                                </HeaderTemplate> 
        
                                <ItemTemplate> 
        
                                    <ul> 
        
                                     <li class="col1"><%# DataBinder.Eval(Container.DataItem, "ContactName") %></li>  
        
                                     <li class="col2"><%# DataBinder.Eval(Container.DataItem, "City") %></li>  
        
                                     <li class="col3"><%# DataBinder.Eval(Container.DataItem, "ContactTitle") %></li>  
        
                                    </ul> 
        
                                </ItemTemplate> 
        
                                <FooterTemplate> 
        
                                 A total of <asp:Literal runat="server" ID="RadComboItemsCount" /> items  
        
                                </FooterTemplate> 
        
                            </telerik:RadComboBox>

answered on 09 Mar 2009, 02:05 PM

Hello Angela,

The demo does show load on demand. The EnableLoadOnDemand property is set to True and the combobox is subscribed to ItemsRequested event.
I suppose you expected to have VirtualScrolling / ShowMoreResults.

In order to have these you should not call the DataBind method in ItemsRequested event. Instead, you should manually iterate through the Rows of the dataset and create the combo's items as shown in this example.

I hope it will be straighforward for you to combine both examples.

Best wishes,
Veselin Vasilev
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answered on 16 Jul 2009, 01:06 PM

comboboxmulticolumn.zip

Hi Jay,

Please find attached a simple page demonstrating the needed approach.

All the best,
Yana
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answered on 17 Mar 2010, 07:52 PM

Well, I am not sure what you are really asking. The attributes collection is pretty straightforward to get in vb.net. For example, I am not using "Address" but "Level1" in the below example:

item template of the combo within the aspx:

ItemTemplate>

<tr>

#DataBinder.Eval(Container, "Attributes(""Level1"")")%>

</td>

#DataBinder.Eval(Container, "Attributes(""Level2"")")%>

</td>

#DataBinder.Eval(Container, "Attributes(""Level3"")")%>

</td>

</tr>

</table>

</ItemTemplate>

in server-side code of the itemsrequested event i have this:

oCBItem =

New RadComboBoxItem()

oCBItem.Attributes.Add(

"Level1", "val for first col")

oCBItem.Attributes.Add(

"Level2", "val for second col")

oCBItem.Attributes.Add(

"Level3", "val for third col")

rcboSystem.Items.Add(oCBItem)

oCBItem.DataBind()

Maybe your problem is that your aspx field does not match your code behind field within the itemseventrequested event. Hope that helps.