retrieve data from class object - error: Object reference not set to an instance of an object.

Hi...
 
my declaration---
newCR.InCharge = new InChargePerson { ReceiveBy = new Staff { UserID = "ADMIN" } };
then i pass it to another function---
db.Add_CRList(newCR);
 
then at function Add_CRList(using store proc) i try retrieve back my value like this---
public void Add_CRList(ChangeRequest CR)
{
       ..........
       cmd.Parameters.AddWithValue("@ReceiveBy", CR.InCharge.ReceiveBy.UserID);
}
 
then error came out:- Object reference not set to an instance of an object. anyone can help me?:)
 
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