How can I get return value of stored procedure when using SqlDataReader?

问题

Is it not possible to get the return value of a stored procedeure when using a datareader? The return value is always null, but the SP returns a valid int from within SSMS.

myCommand.CommandText = "GetVenueVideos";
SqlParameter retVal = new SqlParameter("@returnValue",SqlDbType.Int);
retVal.Direction = ParameterDirection.ReturnValue;
myCommand.Parameters.Add(retVal);
myReader = myCommand.ExecuteReader();
if (myReader.Read() && myReader.HasRows)
{
    int returnValue = Convert.ToInt32(retVal.Value);
    //returnValue is null at this point
}

回答1:

Agh. I've found out the reader has to be closed to get the return value! So inside the if {} block above, I added:

myReader.Close(); // Need to close data reader before getting return value.
int returnValue = (int)myCommand.Parameters["@returnValue"].Value;

...and now it works OK!

来源：https://stackoverflow.com/questions/8093317/how-can-i-get-return-value-of-stored-procedure-when-using-sqldatareader