OnDemand Duplicates Items on virtual scrolling

[Jeff]

I have a RadComboBox with multiple columns of text shown, I have not found a solution to the virtual scrolling duplicating all items in the combo.

Here is the code - aspx:

<telerik:RadComboBox ID="radcmbProduct" runat="server" Width="400px" Height="200px" AllowCustomText="false"
                            EmptyMessage="Select a Product" EnableLoadOnDemand="True" ShowMoreResultsBox="true" DropDownWidth="600px"
                            EnableVirtualScrolling="true" HighlightTemplatedItems="true" MarkFirstMatch="true" ItemsPerRequest="60"
                            NoWrap="true" OnItemsRequested="radcmbProduct_ItemsRequested" OnItemDataBound="radcmbProduct_ItemDataBound">
                            <HeaderTemplate>
                                <ul>
                                    <li class="col1">Title</li>
                                    <li class="col2">System</li>
                                    <li class="col3">Price</li>
                                </ul>
                            </HeaderTemplate>
                            <ItemTemplate>
                                <ul>
                                    <li class="col1">
                                        <%# DataBinder.Eval(Container.DataItem, "Title") %></li>
                                    <li class="col2">
                                        <%# DataBinder.Eval(Container.DataItem, "GameSystemName")%></li>
                                    <li class="col3">
                                        <%# DataBinder.Eval(Container.DataItem, "DisplayPrice")%></li>
                                </ul>
                            </ItemTemplate>
                        </telerik:RadComboBox>

and here is the code behind:

private DataSet GetProductDataSet(string productText)
        {
            string errorMsg = string.Empty;
            DataSet DS = new DataSet();
            Product.GetByName(FacilityID, productText, ref DS, ref errorMsg);
            return DS;
        }

        protected void radcmbProduct_ItemsRequested(object sender, RadComboBoxItemsRequestedEventArgs e)
        {
            DataSet data = GetProductDataSet(e.Text);
            radcmbProduct.DataSource = data;
            radcmbProduct.DataBind();
        }

        protected void radcmbProduct_ItemDataBound(object sender, RadComboBoxItemEventArgs e)
        {
            e.Item.Text = ((DataRowView)e.Item.DataItem)["Title"].ToString() + " | " + ((DataRowView)e.Item.DataItem)["GameSystemName"].ToString() + " | " + ((DataRowView)e.Item.DataItem)["DisplayPrice"].ToString();
            e.Item.Value = ((DataRowView)e.Item.DataItem)["ProductID"].ToString();
        }

So I need to find a way to prevent the items duplicating on scrolling, while maintaining the multiple column text capability.   I have tried adding radcmbProduct.Items.Clear()  prior to the DataBind() in the Items Requested method, however, this had no effect.

I have tried using the attributes as suggested in a previous post however, there were issues with that where the multi-column would only populate the first column.  

I have not found a working solution.

[Yana]

Hi Jeff,

Could you please tell us which version of the controls exactly you're using? Thanks

Kind regards,
Yana
the Telerik team

[Jeff]

2010.2.929.35

[Yana]

Hello Jeff,

Is it possible for you to upgrade to a newer version?  This seems as a  bug which is already fixed.

Best wishes,
Yana
the Telerik team

[Jeff]

Upgraded to latest version: 2010.3.1215.35

Still failed. 

Used Upgrade Wizard to Download latest 2010.3.1317.35

Still fails.

[Kalina]

Hello Jeff,

EnableVirtualScrolling property let you load the RadComboBox items in portions.
Please find a detailed explanation of this property and a sample implementation at this help article.

Kind regards,
Kalina
the Telerik team

[Jeff]

I have read that article, the problem is I cannot use the code as displayed in the article because I am using a Multi-Column Combo unless you can provide an example to use the RadComboBox1.Items.Add method with a templated 3 column combo like this:

<telerik:RadComboBox ID="radcmbProduct" runat="server" Width="250px" Height="200px" AllowCustomText="false"
                            EmptyMessage="Select a Product" EnableLoadOnDemand="True" ShowMoreResultsBox="true" DropDownWidth="525px"
                            EnableVirtualScrolling="true" HighlightTemplatedItems="true" MarkFirstMatch="true" ItemsPerRequest="60" 
                            NoWrap="true" OnItemsRequested="radcmbProduct_ItemsRequested" OnItemDataBound="radcmbProduct_ItemDataBound">
                            <HeaderTemplate>
                                <ul>
                                    <li class="col1">Title</li>
                                    <li class="col2">System</li>
                                    <li class="col3">Price</li>
                                </ul>
                            </HeaderTemplate>
                            <ItemTemplate>
                                <ul>
                                    <li class="col1">
                                        <%# DataBinder.Eval(Container.DataItem, "Title") %></li>
                                    <li class="col2">
                                        <%# DataBinder.Eval(Container.DataItem, "GameSystemName")%></li>
                                    <li class="col3">
                                        <%# DataBinder.Eval(Container.DataItem, "DisplayPrice")%></li>
                                </ul>
                            </ItemTemplate>
                        </telerik:RadComboBox>

[Kalina]

Hello Jeff,

I prepared for you an example with the RadComboBox definition pasted here and the Northwind database.
Please note that I have used the RadComboBox Attributes collection – you can find more details about this collection here.
Additionally in order to instantiate the item template I databinded every item explicitly after adding it to RadComboBox items collection.

I hope this helps.

Regards,
Kalina
the Telerik team

[Jeff]

Thank you!  This is now working for me.

[joseph]

The key for me was to make sure that the following code line was in place

            if (e.NumberOfItems == searchResults.TotalRecords)
            {
                e.EndOfItems = true;
                return;
            }