RadCombobox : Insert Item After DataBinding

[Muhammad]

I have a radcombobox and in that I have placed one checkbox after databinding I want to insert one more checkbox inside that radcombobox to select all items.

<telerik:RadComboBox ID="cmbRoleName" EmptyMessage="- please select group -" runat="server"
                                     AutoCompleteSeparator="true" HighlightTemplatedItems="true"
                                    AutoPostBack="True" AllowCustomText="true" OnClientDropDownClosed="onDropDownClosing">
                                    <Items>
                                        <telerik:RadComboBoxItem Value="0" Text="-- Select All Users --" />
                                    </Items>
                                    <ItemTemplate>
                                        <table border="0" cellpadding="0" cellspacing="0">
                                            <tr>
                                                <td>
                                                    <asp:CheckBox runat="server" ID="chkRole" Text='<%#DataBinder.Eval(Container.Dataitem,"RoleName")%>'
                                                        Onclick="chkBox_Click(this)" />
                                                </td>
                                            </tr>
                                        </table>
                                    </ItemTemplate>
                                </telerik:RadComboBox>

I have tried to do this on server side like this but the problem is that two checkboxes are appearing one with text and without text. Any Help would be really appreciated.

Protected Sub CreateSelectAllUsersCheckBox()
        Dim chkSelectAllUsers As New CheckBox
        chkSelectAllUsers.Text = "Select All Users"
        chkSelectAllUsers.ID = "chk1"
        Dim radComboBoxItem As New RadComboBoxItem
        radComboBoxItem.Text = "Select All Users"  
radComboBoxItem.Controls.Add(chkSelectAllUsers)     
        cmbRoleName.Items.Insert(0, radComboBoxItem)
    End Sub

[Simon]

Hi Muhammad,

You can resolve this by calling DataBind on radComboBoxItem after you add it to the Items collection of the RadComboBox.

Regards,
Simon
the Telerik team

[Muhammad]

I don't understand how it can be done ... If you can provide me some code so I can easily understand because I am just start using telerik controls.

[Simon]

Hi Muhammad,

The DataBind method is a method of the RadComboBoxItem class, so you can directly invoke it on a RadComboBoxItem object.

Here is how you need to modify your code to make this work:

Protected Sub CreateSelectAllUsersCheckBox()
        Dim chkSelectAllUsers As New CheckBox
        chkSelectAllUsers.Text = "Select All Users"
        chkSelectAllUsers.ID = "chk1"
        Dim radComboBoxItem As New RadComboBoxItem
        radComboBoxItem.Text = "Select All Users"
    radComboBoxItem.Controls.Add(chkSelectAllUsers)
        cmbRoleName.Items.Insert(0, radComboBoxItem)

        radComboBoxItem.DataBind()
    End Sub

I hope this helps.

Greetings,
Simon
the Telerik team

[Frankie]

Hi, I have my code as below, however, the inserted item after databind() is still not in the dropdown.. anything wrong with my code?

private DataTable GetDataTable(string queryString)
{
    String ConnString = ConfigurationManager.ConnectionStrings["NxtFinancialMain_ConnString"].ConnectionString;
    SqlConnection MySqlConnection = new SqlConnection(ConnString);
    SqlDataAdapter MySqlDataAdapter = new SqlDataAdapter();
    MySqlDataAdapter.SelectCommand = new SqlCommand(queryString, MySqlConnection);

    DataTable myDataTable = new DataTable();
    MySqlConnection.Open();
    try
    {
        MySqlDataAdapter.Fill(myDataTable);
    }
    finally
    {
        MySqlConnection.Close();
    }

    return myDataTable;
}


protected void ParentId_DataBinding(object sender, System.EventArgs e)
{
    //
    ddlBox3.Items.Insert(0, new RadComboBoxItem("Root", "0"));

    // the dropdown list is now only with SBG... BusinessUnitTypeId = 2
    ddlBox3.DataSource = GetDataTable("SELECT [Id], [Code], [Name] FROM [BusinessUnits] WHERE [BusinessUnitTypeId]=2");
    ddlBox3.DataTextField = "Code";
    ddlBox3.DataValueField = "Id";
    ddlBox3.DataBind();
    //ddlBox3.SelectedIndex = 0;

}

Regards,
Frank

[Simon]

Hello Frankie,

Calling RadComboBox.DataBind() clears all previously existing items in the control. You can preserve them if you set the RadComboBox.AppendDataBoundItems property to true.

Best wishes,
Simon
the Telerik team