Dynamically Created RadComboBox

[Zash]

Hi,

I created radcombobox dynamically. I want to add EnableLoadOnDemand functionality from codebehind. I need a sample of code in asp.net having this functionality doing from codebehind.

Thanks.

[Princy]

Hello Zash,

You can try the following code snippet.

C#:

protected void Page_Load(object sender, EventArgs e)
   {
    RadComboBox rdcmb = new RadComboBox();
    rdcmb.ID = "RadComboBox1";
    rdcmb.AutoPostBack = true;
    rdcmb.MarkFirstMatch = true;
    rdcmb.AutoCompleteSeparator = ",";
    rdcmb.EnableLoadOnDemand = true;
    rdcmb.EnableAutomaticLoadOnDemand = true;
    rdcmb.LoadingMessage = "Loading...";
    SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ToString());
    String s = "select FirstName,EmployeeID from Employees";
    con.Open();
    SqlDataAdapter dr = new SqlDataAdapter(s, con);
    DataTable dt = new DataTable();
    dr.Fill(dt);
    con.Close();
    rdcmb.DataSource = dt;
    rdcmb.DataTextField = "FirstName";
    rdcmb.DataValueField = "EmployeeID";
    rdcmb.DataBind();
    form1.Controls.Add(rdcmb);
   }

Thanks,
Princy.

[Ivana]

Hello Rukunuz,

To see how RadComboBox is bound to various data sources, you could refer to the DataBinding section of the Combo's online documentation.

To enable the load on demand functionality, you need to set the property LoadOnDemand to true, and subscribe to the OnItemsRequested server-side event, where the items will be populated when they are requested on demand (which happens when the user opens the drop-down list, or type in the input field), as in the code-block below:

protected void Page_Load(object sender, EventArgs e)

{

    RadComboBox combo = new RadComboBox();

    combo.ID = "RadComboBox1";

    combo.EnableLoadOnDemand = true;

    combo.ItemsRequested += new RadComboBoxItemsRequestedEventHandler(combo_ItemsRequested);

    form1.Controls.Add(combo);

}


protected void combo_ItemsRequested(object sender, RadComboBoxItemsRequestedEventArgs e)

{

    RadComboBox combo = (RadComboBox)sender;

    for (int i = 0; i <= 3; i++)

    {

        combo.Items.Add(new RadComboBoxItem("item_" + i.ToString()));

    }

}

More about load on demand mechanism, could be found at the following help article: RadComboBox: LoadOnDeman.

All the best,
Ivana
the Telerik team