How to use C# string Copy

using System;
using System.Windows.Forms;

namespace WindowsApplication1
{
 public partial class Form1 : Form
 {
  public Form1()
  {
   InitializeComponent();
  }

  private void button1_Click(object sender, EventArgs e)
  {
   string str1 = null;
   string str2 = null;

   str1 = "CSharp Copy() test";
   str2 = string.Copy(str1);

   MessageBox.Show(str2); 
  }
 }
}

When you run this C# source code you will get same content of str1 in str2