ExecuteNonQuery() Exception with date insertion

Question

I have a stored procedure to insert record and returns the ID of record inserted.

Here is my SQL implementation:

ALTER PROCEDURE InsertViolation 
    @FactoryName nvarchar(50) ,
    @Type  nvarchar(100),
    @Location nvarchar(30) ,
    @Desc nvarchar(300),
    @Severity nvarchar(300),
    @DateObserved datetime,
    @ViolationNumber bigint output
AS
BEGIN
    SET NOCOUNT ON;

INSERT INTO Violation
       (Violation_Factory_Name
       ,Violation_Type
       ,Violation_Location
       ,Violation_Desc
       ,Violation_Severity
       ,Violation_Date_Observed)
 VALUES
       (@FactoryName
       ,@Type
       ,@Location
       ,@Desc
       ,@Severity
       ,@DateObserved)
SET @ViolationNumber=SCOPE_IDENTITY()
      RETURN  @ViolationNumber
END

and i have this C# code to invoke this procedure:

 public static long Insert_Violation(Model.Violation violation)
 {
        string strStoredProcedureName = "InsertViolation";
        SqlCommand cmd = new SqlCommand(strStoredProcedureName);
        string strConnString = ConfigurationManager.ConnectionStrings["ViolationConnection"].ConnectionString;

        SqlConnection con = new SqlConnection(strConnString);
        cmd.Connection = con;
        cmd.CommandType = CommandType.StoredProcedure;
        cmd.Parameters.AddWithValue("@FactoryName", violation.FactoryName);
        cmd.Parameters.AddWithValue("@Type", violation.ViolationType);
        cmd.Parameters.AddWithValue("@Location", violation.Location);
        cmd.Parameters.AddWithValue("@Desc", violation.ViolationDesc);
        cmd.Parameters.AddWithValue("@Severity", violation.Serverity);
        cmd.Parameters.AddWithValue("@DateObserved", violation.DateObserved);
        cmd.Parameters.AddWithValue("@ViolationNumber", -1).Direction = ParameterDirection.Output;

        try
        {
            con.Open();
            cmd.ExecuteNonQuery();

            return (long) cmd.Parameters["@ViolationNumber"].Value;

        }
        catch(Exception ex)
        {
            throw new Exception(ex.Message + " Date Parameter value is " + cmd.Parameters["@DateObserved"].Value + " \n DateTime Object converted to string value is " + violation.DateObserved.ToString());
            return -1;
        }
        finally
        {
            con.Dispose();
            cmd.Dispose();
        }
    }

I found the row has been inserted in the database but an exception is thrown at cmd.ExecuteNonQuery(); the problem is that I used the violation.DateObserved which is C# DateTime object and the corresponding parameter and field in DB is of type datetime

Here is the exception message that caught and I used throw exception to print it :

System.Exception: Specified cast is not valid. Date Parameter value is 15/12/2012 12:00:00 DateTime Object converted to string value is 15/12/2012 12:00:00

So I could not get the record number instead my function returns -1 as the catch is visited.

Answer 1

The return statement implicitly casts the result as an integer; you should therefore unbox as int , not long :

return (int) cmd.Parameters["@ViolationNumber"].Value;

If the value you have won't fit it an int , then either use an out parameter, or select the value and use ExecuteScalar .