The SqlParameter is already contained by another SqlParameterCollectiont

The SqlParameter is already contained by another SqlParameterCollection.

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.ArgumentException: The SqlParameter is already contained by another SqlParameterCollection.

Source Error: 


Line 21:             SqlParameter[] parameter = null;
Line 22:             parameter = new[] { new SqlParameter("ExamId ", ExamId) };
Line 23:             return new eSoftExam().GetQueryContext().ExecuteStoreQuery<ExamDetails>("EXEC [dbo].spEX_GetExamDetailss @ExamId", parameter).FirstOrDefault();
Line 24: 
Line 25:         }