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[Solved] Creating templated RAD Combo Box at runtime

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ComboBox

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

Boris asked on 08 Jan 2010, 07:54 PM

I need to dynamically create RAD Combo Boxes and databind them at runtime. I have a template which consists of a checkbox and a label that holds the "text" of the combo box. Here is the template definition:

                        class GroupTopicTemplate : ITemplate         
                {         
                    public void InstantiateIn(Control container)         
                    {         
                        HtmlGenericControl div = new HtmlGenericControl("div");         
                        CheckBox chkSelected = new CheckBox();         
                        chkSelected.ID = "chkSelected";         
                        int rowNumber = int.Parse(container.Parent.ClientID.Substring(container.Parent.ClientID.Length - 1)) + 1;         
                        chkSelected.Attributes.Add("onclick", "onCheckBoxClick(" + rowNumber.ToString() + ")");         
                        div.Controls.Add(chkSelected);         
                        Label lblName = new Label();         
                        lblName.Text = "Text";         
                        lblName.DataBinding += new EventHandler(lblName_DataBinding);         
                        lblName.ID = "lblName";         
                        container.Controls.Add(div);         
                    }         
                     
                    void lblName_DataBinding(object sender, EventArgs e)         
                    {         
                        Label target = (Label)sender;         
                        RadComboBoxItem item = (RadComboBoxItem)target.BindingContainer;         
                        string itemText = (string)DataBinder.Eval(item, "Text");         
                        target.Text = itemText;         
                    }         
                }         

The combo box is created in Page_Init as follows:

                            RadComboBox rcGroupTopics = new RadComboBox();         
                    rcGroupTopics.ID = "rcGroupTopics" + rowString;         
                    rcGroupTopics.EmptyMessage = "None";         
                    rcGroupTopics.HighlightTemplatedItems = true;         
                    rcGroupTopics.AllowCustomText = true;         
                    rcGroupTopics.Skin = "WebBlue";         
                    rcGroupTopics.ItemTemplate = new GroupTopicTemplate();         
                    td.Controls.Add(rcGroupTopics);         

The combo box is populated as follows:

                    DataView dv = new DataView(dt);         
                     
            dv.Sort = "name";         
                     
            TopicDropDownList.DataSource = dv;         
            TopicDropDownList.DataTextField = "name";         
            TopicDropDownList.DataValueField = "tagname";         
            TopicDropDownList.DataBind()         

I tried to put the above code in Page_Init (below the above code) and in Page_Load. The problem is, InstantiateIn() is not called until DataBind(), so the data binding event handler is attached too late and the label has no text. Is there a way around this?

Thanks in advance,

Boris Zakharin

3 Answers, 1 is accepted

Accepted

answered on 11 Jan 2010, 02:56 PM

Hi Boris,

First, you've missed to add the label to to div in the template:

Label lblName = new Label();

lblName.Text = "Text";

lblName.DataBinding += new EventHandler(lblName_DataBinding);

lblName.ID = "lblName";

div.Controls.Add(lblName);

container.Controls.Add(div);

and also you should set the template in the OnInit event handler:

RadComboBox rcGroupTopics = new RadComboBox();

rcGroupTopics.ItemTemplate = new GroupTopicTemplate();

Best regards
Yana
the Telerik team

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