Thread: how to add Form into Dll

how to add form into dll and Inject to show form ?
i trial this code

Code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace ClassLibrary1
{
    public class Class1
    {
        System.Windows.Forms.Form Fo = new System.Windows.Forms.Form();
             public  void Main()
             {
                 Fo.Show();
}
               public  void New()
                     {
                         Fo.Show();
                     }
        public void Form(ref System.Windows.Forms.Form Fr)
        {
            Fo.FormBorderStyle = FormBorderStyle.None;
            Fo.BackColor = System.Drawing.Color.Red;
            Fo.Size = new System.Drawing.Size(224, 268);
            Fr.Controls.Add(Fo);
            Fo.Show();
        }
        public void Items(ref System.Windows.Forms.Form Add)
        {
            System.Windows.Forms.Button btn = new System.Windows.Forms.Button();
            btn.Location = new System.Drawing.Point(34, 105);
            btn.Size = new System.Drawing.Size(40, 20);
            btn.Text = "Button1";
            Add.Controls.Add(btn);
        }
    }
}

but not work and remove class , add form not work too i can't Inject it