show properties in designer in visual studio

If you need to show a property of your own in the design window, you have to base a from on a derived form.
I.e.

public class MyFormWithProperty : Form
   {
   public int MyProperty { get; set; }
   public MyFormWithPropertyfrmTesting()
       {
       InitializeComponent();
       }
   }

And then derive your form instance from that:

public class MyFormInstance : MyFormWithProperty
   {
   public MyFormInstance()
       {
       InitializeComponent();
       }
   }

When you look at the properties for MyFormInstance, it will have the MyProperty property.

It sounds confusing: but just try it - you will see what I mean!