C#

public class Form1 : System.Windows.Forms.Form<br />
{<br />
      private Form2 form2 = new Form2();<br />
...}

private void button1_Click(object sender, System.EventArgs e)<br />
{<br />
    Form2 frm2 = new Form2();<br />
    frm2.Show();<br />
            //This is where you would set you reference equal to your instance.<br />
    form2 = frm2;<br />
}

public class Form2 : System.Windows.Forms.Form<br />
{<br />
    public System.Windows.Forms.Button button1;<br />
    ...}

private void button1_Click(object sender, System.EventArgs e)<br />
{<br />
MessageBox.Show(System.Web.HttpUtility.HtmlDecode("http://www.codeproject.com"));<br />
}<br />

private void Form1_DoubleClick(object sender, System.EventArgs e)<br />
	{<br />
		Form frm=sender as Form;<br />
		if(frm!=null)//casting is success<br />
		MessageBox.Show(frm.Name);<br />
	}