c# - How to First Form Timer Start from Second form -

i have tried many time access , change property of control timer code please me

public partial class form1 : form {     public form1()     {         initializecomponent();     } }  public partial class form2 : form  {      public form2()     {         initializecomponent();        }      private void button2_click(object sender, eventargs e)     {         form1 frm = new form1();         frm.timer1.enabled = true;           } } 

and had tried on loading constructor

public partial class form1 : form {     public form1()     {         initializecomponent();     }  }   public partial class form2 : form  {      form1 mainform;       public form2(form1 mainform)     {         initializecomponent();         this.mainform=mainform;     }      public form2()     {         initializecomponent();        }      private void button2_click(object sender, eventargs e)     {         mainform.timer1.enabled = true;                } } 

when use constructor on loading occurred exception error object reference not found please me .................... , regard muhammad azam khan

in form1:

 public bool timerenable{       get{ return  timer1.enabled;}       set{             timer1.enabled = value;       }  } 

in form2:

 private void button2_click(object sender, eventargs e)  {     form1 frm = new form1();     frm.timerenable = true;  }