System.Runtime.Serialization.SerializationException (PublicKeyToken=null' is not marked as serializable)

Hello

  I am getting below error while deleting an item from datalist control.

  Please give me any suggestion. Needed help Urgently .

Thanks. 

Server Error in '/' Application.


Type 'Dyve.BL.Articles.LicenseCollection' in Assembly 'Dyve.BL, Version=1.0.0.9, Culture=neutral, PublicKeyToken=null' is not marked as serializable.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Runtime.Serialization.SerializationException: Type 'Dyve.BL.Articles.LicenseCollection' in Assembly 'Dyve.BL, Version=1.0.0.9, Culture=neutral, PublicKeyToken=null' is not marked as serializable. ...