Change smtp from mail address using c#

Hi,
  i am sending email using gmail smtp credentials. My problem is that, i want to use different email id and username as credentials.

    <smtp from="MySender@gmail.com" deliveryMethod="Network">
  <network host="smtp.gmail.com" port="25" userName="MyUser@gmail.com" password="mypassword"  />
  </smtp>
   
    Now i want to show from address ("MySender@gmail.com") in client's from address, rather than userName "MyUser@gmail.com".
   
    Would you please help me to show from address ("MySender@gmail.com"), than userName "MyUser@gmail.com"
   
Thanks