Not marked as Serializable ....?

Question

Hi Frnds,

 

   I am taking backup of object my using Serialize method , here i am getting error  not marked as Serializable but every thing is marked as Serializable, 

 I want to take a backup of object any other method is there please tell me.

    

using (MemoryStream ms = new MemoryStream())

{

BinaryFormatter bf = new BinaryFormatter();

bf.Serialize(ms, MyObj);  // -- Error 

ms.Position = 0;

MyObjBackup = (MyClass)bf.Deserialize(ms);

}

 

 Thanks in Advance.