RadComboBox Item Duplicate

[Srujan]

Hi ,

I have RadCombo box which is using ItemRequested event to load items , when I click on "ShowMoreResults" list of items are added again and total count is doubled  . I used RadCombo box clear items before rebinding but still the issue occurs ,can anybody suggest how to go about the issue .

Regards
Srujan.N

[Charles]

Did you ever find an answer to your question? I have the same problem. When I click the more items control, I get duplicate items.

[Ivana]

Hello Srujan and Charles,

Take a look at the following help article explaining on how to implement the ShowMoreResultsBox/Virtual Scrolling functionality: https://docs.telerik.com/devtools/aspnet-ajax/controls/combobox/load-on-demand/showmoreresultsbox-virtual-scrolling. If you, however, are using automatic load on demand then all this should be taken care of internally.

If you still have troubles, could you paste here the markup of the control and the code involved in the troubled behavior?

Regards,
Ivana
the Telerik team

 

 

[Fred]

Hi,

I do have the same exact issue. Whenever I click on ShowMoreResults, the items get duplicated. I searched online for a solution, but I could not find anything. 

Regards.

[Princy]

Hi Fred,

I suppose you are missing the server-side logic in the ItemsRequested event handler that loads only the needed portion of Items.

C#:

protected void RadComboBox1_ItemsRequested(object sender, RadComboBoxItemsRequestedEventArgs e)
{
    string sql = "SELECT * from Customers WHERE CompanyName LIKE '" + e.Text + "%'";
    SqlDataAdapter adapter = new SqlDataAdapter(sql, ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString);
    DataTable data = new DataTable();
    adapter.Fill(data);
    //loads only the needed portion of Items
    try
    {
        int itemsPerRequest = 10;
        int itemOffset = e.NumberOfItems;
        int endOffset = itemOffset + itemsPerRequest;
        if (endOffset > data.Rows.Count)
        {
            endOffset = data.Rows.Count;
        }
        for (int i = itemOffset; i < endOffset; i++)
        {
            RadComboBox1.Items.Add(new RadComboBoxItem(data.Rows[i]["CompanyName"].ToString(), data.Rows[i]["CompanyName"].ToString() + "'"));
        }
        if (data.Rows.Count > 0)
        {
            e.Message = String.Format("Items <b>1</b>-<b>{0}</b> out of <b>{1}</b>", endOffset.ToString(), data.Rows.Count.ToString());
        }
        else { e.Message = "No matches"; }
    }
    catch
    {
        e.Message = "No matches";
    }
}

Please take a look into this documentation and demo for the complete code.

Please provide your full code if doesn't helps.

Regards,
Princy.

[Matt]

Please post solutions and not links to solutions. Telerik pages are not maintained to redirect to the correct information.

[Peter Milchev]

Hello Matt,

We are sorry for the broken redirect. The correct link is https://docs.telerik.com/devtools/aspnet-ajax/controls/combobox/load-on-demand/showmoreresultsbox-virtual-scrolling.

Also, Princy has provided the solution and also a live example can be found in the Online Demos - https://demos.telerik.com/aspnet-ajax/combobox/examples/populatingwithdata/autocompletesql/defaultcs.aspx.

Generally, the idea is to load only the records that are requested by the control instead of all records: 

for (int i = itemOffset; i < endOffset; i++)
{
    RadComboBox1.Items.Add(new RadComboBoxItem(data.Rows[i]["CompanyName"].ToString(), data.Rows[i]["CompanyName"].ToString() + "'"));
}

Regards,
Peter Milchev
Progress Telerik