Accessing Checked Items in RadMenu in Code Behind

Question

User-971051533 posted

I have a RadMenu that I have added checkboxes to the child menu items and the checkboxes are then bound to a value. I need to be able to allow the user to check items in the menu and then when a submit button is clicked it will filter a RadGrid. I'm not sure how to access the checked values in the RaadMenu in submit button click event? I'll paste my code below.

<telerik:RadMenu ID="handsetMenu" runat="server" OnClientItemClicking="DisableRootClick" OnItemClick="handsetMenu_ItemClick">   
                    <Items>   

                    </Items>                                                     
                </telerik:RadMenu> 

 foreach (var cat in CatProdList)
    {
        var itemCategory = new RadMenuItem(cat.Category.Name);

        handsetMenu.Items.Add(itemCategory);

        var option = cat.ProdAttributesTuple.GroupBy(a => a.Item2.Attribute.Value).ToList();
        foreach (var attr in option)
        {
            //itemCategory.Items.Add(new RadMenuItem(attr.Key));
            var item = new RadMenuItem(attr.Key);

            itemCategory.Items.Add(item);

            CustomContentTemplate template = new CustomContentTemplate();

            item.ContentTemplate = new CustomContentTemplate();
            template.InstantiateIn(item);
            item.DataBind();                

        }

    }

class CustomContentTemplate : ITemplate
{
    public void InstantiateIn(Control container)
    {
        CheckBox cb = new CheckBox();
        cb.DataBinding += new EventHandler(cb_DataBinding);
        container.Controls.Add(cb);

    }

    private void cb_DataBinding(object sender, EventArgs e)
    {
        CheckBox target = (CheckBox)sender;
        RadMenuItem item = (RadMenuItem)target.BindingContainer;
        target.Text = item.Text;
    }
}

 protected void btnSubmit_Click(object sender, EventArgs e)
{

}

 

Answer 1

User-271186128 posted

Hi Holly Quinn,

As for this issue, please refer to the following sample and try to use FindControl method to find the relevant CheckBox.

<telerik:RadButton runat="server" ID="button0" Text="UncheckCheckBox" OnClick="button0_Click">
    </telerik:RadButton> 
    <telerik:RadPanelBar ID="RadPanelBar0" runat="server">
    <Items>
        <telerik:RadPanelItem Text="PanleItem1">
            <HeaderTemplate>
                <asp:CheckBox runat="server" ID="checkBox1" Text="CheckBox1" Checked="true" />
            </HeaderTemplate>
            <ContentTemplate>
            </ContentTemplate>
        </telerik:RadPanelItem>
    </Items>
</telerik:RadPanelBar>

Code Behind:

protected void button0_Click(object sender, EventArgs e)
{
    RadPanelItem item = RadPanelBar0.Items[0];
    CheckBox CheckItem = item.Header.FindControl("checkBox1") as CheckBox;
    CheckItem.Checked = false;
}

For more details, please see: http://docs.telerik.com/devtools/aspnet-ajax/controls/panelbar/templates/accessing-controls-inside-templates

Besides, since this issue is related to the Telerik control, if you have any further question about it, I suggest you could post the question to Telerik Forums.

Best Regards,
Dillion

Answer 2

User-971051533 posted

Hi Zhi.  Thanks for your help.  I'm not sure the RadMenu works the same way that the RadPanel does though.  I am getting the error message:

An exception of type 'System.NullReferenceException' occurred in App_Web_umdevm1i.dll but was not handled in user code

Additional information: Object reference not set to an instance of an object.

on the last line of my code here:

 protected void btnSubmit_Click(object sender, EventArgs e)
    {
        RadMenuItem item = handsetMenu.Items[0];
        CheckBox CheckItem = item.FindControl("cb") as CheckBox;
        CheckItem.Checked = false;  
           
    }

I think it can't find the CheckBox template that I created in the code behind:

 class CustomContentTemplate : ITemplate
    {
        public void InstantiateIn(Control container)
        {
            CheckBox cb = new CheckBox();

            cb.Text = "Text";

            cb.DataBinding += new EventHandler(cb_DataBinding);
            container.Controls.Add(cb);            
            
        }

        private void cb_DataBinding(object sender, EventArgs e)
        {
            CheckBox target = (CheckBox)sender;
            RadMenuItem item = (RadMenuItem)target.BindingContainer;
            target.Text = item.Text;                    
        }
    }

Do you know what I'm doing wrong?  If you need to see anymore code just let me know.  Thanks.

Answer 3

User-271186128 posted

Hi hollyquinn,

With reference to the following link, it seems the RadCombobox control that has already a build-in property - CheckBoxes that you can set to true - that implements most of the functionality you describe. 

http://www.telerik.com/forums/how-to-get-access-to-checkbox-within-radmenu

Besides, I suggest you could refer to the following code to add templates to RadMenu at runtime.

protected override void OnInit(EventArgs e)
{    RadMenu1.ItemTemplate = new TextBoxTemplate();    
    base.OnInit(e);
}

protected void Page_Load(object sender, EventArgs e)
{    
    if (!Page.IsPostBack)
    {        
        RadMenu1.Items.Add(new RadMenuItem("MenuItem1"));
        RadMenu1.Items.Add(new RadMenuItem("MenuItem2"));
    }    
    RadMenu1.DataBind();
}

class TextBoxTemplate : ITemplate
{    
    public void InstantiateIn(Control container)    
    {        
        Label label1 = new Label();
        label1.ID = "ItemLabel";
        label1.Text = "Text";
        label1.Font.Size = 15;
        label1.Font.Bold = true;
        label1.DataBinding += new EventHandler(label1_DataBinding);
        container.Controls.Add(label1);
    }    

    private void label1_DataBinding(object sender, EventArgs e)
    {        
        Label target = (Label)sender;
        RadMenuItem item = (RadMenuItem)target.BindingContainer;
        string itemText = (string)DataBinder.Eval(item, "Text");
        target.Text = itemText;
    }
}         

For more details, please see: http://docs.telerik.com/devtools/aspnet-ajax/controls/menu/templates/adding-templates-at-run-time

As indicated in my previous reply, this issue is related to the Telerik control, if you have any further question about it, I suggest you could post the question to Telerik Forums.

Best Regards,
Dillion

Answer 4

User-971051533 posted

Hi Dillion,

I did decide to go with the RadComboBox, but I can't get it to work either.  I'm haivng a problem finding the RadComboBox inside the filter template.  I've put in a ticket with Telerik and posted in their forums, they haven't responded to either one.  I thank you for your help with this.