Office Powerpoint Ribbon menu item access?

Question

Is it possible from the Powerpoint slide, I can access to a Ribbon menu item? For example, I have a checkbox under the Ribbon Menu. Now I want that when I click a shape, this checkbox should be checked?

The issue seems to be easy, but I cannot find a way to do it. Do you have any idea? (prefer in C#)

EDITED with CODE

The custom ribbon menu

public partial class RibbonMenu
{
        private void RibbonMenu_Load(object sender, RibbonUIEventArgs e)
        {

        }

        public void ChangeCheckBox()
        {
              System.Windows.Forms.MessageBox.Show("The CheckBox is changed");
              this.checkBox.Checked = true;
              this.checkBox.Label = "AAAAAAA"
        }

}

Catch the selection event

public partial class ThisAddIn
{
        private RibbonMenu menu;

        private void ThisAddIn_Startup(object sender, System.EventArgs e)
        {
            CreateRibbonExtensibilityObject();
            Application.WindowSelectionChange   += new PowerPoint.EApplication_WindowSelectionChangeEventHandler(Application_WindowSelectionChange);

        }

        protected override Microsoft.Office.Core.IRibbonExtensibility CreateRibbonExtensibilityObject()
        {
            this.menu = new RibbonMenu();

            return Globals.Factory.GetRibbonFactory().CreateRibbonManager(new Microsoft.Office.Tools.Ribbon.IRibbonExtension[]
             {
                  this.menu                  
             });
        }

        private void Application_WindowSelectionChange(PowerPoint.Selection Sel)
        {
            //.... Check if the selection is a shape's selection
            this.menu.ChangeCheckBox();         
        }
}

The Result is the message box "The CheckBox is changed"" is appeared, but the checkbox is not cheched and the label is not changed to "AAAAAA"

Answer 1

Using Globals to access the Office Ribbon Menu Item as follow:

private void Access_All_Ribbons_Globals()
{
    Globals.Ribbons.Ribbon1.comboBox1.Text = "Hello World";
}

Answer 2

I think you have to use the Application.WindowSelectionChange event for this.

According to MSDN:

Occurs when the selection of text, a shape, or a slide in the active document window changes, whether in the user interface or in code.

It will give you a Selection object which you can use further on.

Signature of the event handler:

void (Microsoft.Office.Interop.PowerPoint.Selection selection)