Basic ComboBoxItem Binding Programmatically In C# WPF

Question

I am trying to change ComboBoxItem Template Programmatically

//Main Style
Style style = new Style() { TargetType = typeof(ComboBoxItem) };
//Set Template
ControlTemplate temp = new ControlTemplate(typeof(ComboBoxItem));
style.Setters.Add(new Setter() { Property = Control.TemplateProperty, Value = temp });

//Item Border
FrameworkElementFactory itemB = new FrameworkElementFactory(typeof(Border));
itemB.SetValue(Border.BorderBrushProperty, Brushes.Red);
itemB.SetValue(Border.WidthProperty, (double)500);
itemB.SetValue(Border.HeightProperty, (double)30);
itemB.SetValue(Border.BorderThicknessProperty, new Thickness(2));
itemB.SetValue(Border.BackgroundProperty, Brushes.GreenYellow);
temp.VisualTree = itemB;

//Item Label
FrameworkElementFactory itemT = new FrameworkElementFactory(typeof(Label));
itemT.AppendChild(itemB);
itemT.SetValue(Label.ForegroundProperty, Brushes.Red);

/* This Part Is Not Working*/
itemT.SetBinding(Label.ContentProperty, new Binding { RelativeSource = RelativeSource.Self });
        
//Set Template
Application.Current.Resources[typeof(ComboBoxItem)] = style;

I Also Tried This

itemT.SetBinding(Label.ContentProperty, new Binding { Source = ComboBoxItem.ContentProperty });

The problem is that items name are not getting shown in dropdown list.

This is how i am adding comboBox

//ComboBox
ComboBox combobox = new ComboBox() {Height = 30, Width = 500};
combobox.Items.Add("OK 1");
combobox.Items.Add("OK 2");
combobox.Items.Add("OK 3");
combobox.Items.Add("OK 4");

Here is how my dropdown looks

Answer 1

Besides that it is unclear why you won't simply do this in XAML, both

itemT.SetBinding(Label.ContentProperty,
   new Binding { RelativeSource = RelativeSource.Self });

and

itemT.SetBinding(Label.ContentProperty,
    new Binding { Source = ComboBoxItem.ContentProperty });

are wrong for two reasons. They are missing a property Path and use the wrong binding source object.

In a ControlTemplate you would bind to the Content property of the templated parent element:

itemT.SetBinding(Label.ContentProperty,
    new Binding
    {
        Path = new PropertyPath(ComboBoxItem.ContentProperty),
        // or Path = new PropertyPath(nameof(ComboBoxItem.Content)),
        RelativeSource = RelativeSource.TemplatedParent
    });

You may also use a TemplateBinding by

itemT.SetValue(Label.ContentProperty,
    new TemplateBindingExtension(ComboBoxItem.ContentProperty));

---

There should also be

itemB.AppendChild(itemT);

instead of

itemT.AppendChild(itemB);