how to pass object of class in viewstate using serialization in asp dot net

When one needs to maintain the object in viewstate, it has to be serializable, because it by default gets serialized to encrypted Base64 string. Please check the class which you are instantiating is a serializable class. Here is something to give you an idea
[Serializable]
public class Apple
{
public string Color { get;set;}
public decimal Weight { get;set;}
}


public Apple MyApple
{
get
{
if(ViewState["AppleColor"] !=null)
return (Apple)ViewState["AppleColor"];
else
return null;
}
set
{
ViewState["AppleColor"] = value;
}
}


Apple apple = new Apple();
apple.Color = "Red";
apple.Weight = 0.5m;


//set the property in viewstate
MyApple = apple;


Apple newApple = MyApple;