C# stored procedure returning -1 Repeatedly

Question

I have repeatedly test this #blankety-blank# stored procedure on SQL Server, and it returns either 0 or number of rows, but in C# I am always getting -1. I have been debugging this #blank# thing for hours and always -1.

Here's the stored procedure code.

Create procedure [dbo].[sp_enter_new_student] 
    @Prenom_detudiant [varchar](50)  = NULL, 
    @nom_detudiant [varchar](50)  = NULL,
    @nationalite_detudiant [varchar](40)  = NULL,
    @langue_parle [varchar](15)  = NULL,
    @nombre_denfants [int] = NULL,
    @sexe_detudiant [char](1) = NULL,
    @program_pk [int] = NULL,
    @Numero_detudiant int = NULL
As 
Declare @numOfRowsBefore int = 0; 
declare @numOfRowsAfter int = 0; 
declare @Error int = -100; 
BEGIN  
    SET NOCOUNT ON; 
    select @numOfRowsBefore = COUNT(*) from tbl_students where Numero_detudiant = @Numero_detudiant; 

    if (@numOfRowsBefore > 0)
    begin
        Print "Student already exists, Insertion will fail!";
        Print "Insertion Failure ! " + CONVERT(varchar(10), @numOfRowsBefore);
        return @numOfRowsBefore; -->  -1 indicates insertion failure
    End
    else if (@numOfRowsBefore = 0)
    begin
        Print "Student doesn't exists, Insertion will be Success!";
        Print "Insertion Success ! " + CONVERT(varchar(10), @numOfRowsBefore);
        return @numOfRowsBefore; -->  -1 indicates insertion failure
    End

END 

---

And here's a C# code

---

public int enregistreNouveauEtudiant(string Prenom_detudiant, string nom_detudiant, string nationalite_detudiant, string langue_parle, string nombre_denfants, string sexe_detudiant, string program_pk, string Numero_detudiant)
{
    int numberOfRowsInserted = 0;
    //try
    //{ 

    SqlConnection connection = this.GetConnection();
    SqlCommand insertStudentCommand = new SqlCommand("sp_enter_new_student", connection);
    connection.Open();
    insertStudentCommand.CommandType = CommandType.StoredProcedure;

    //insertStudentCommand.Parameters.Add("@ID", SqlDbType.Int);
    //insertStudentCommand.Parameters["@ID"].Direction = ParameterDirection.Output;

    insertStudentCommand.Parameters.Add("@Prenom_detudiant", SqlDbType.VarChar, 50).Value = Prenom_detudiant;
    insertStudentCommand.Parameters.Add("@nom_detudiant", SqlDbType.VarChar, 50).Value = nom_detudiant;
    insertStudentCommand.Parameters.Add("@nationalite_detudiant", SqlDbType.VarChar, 40).Value = nationalite_detudiant;
    insertStudentCommand.Parameters.Add("@langue_parle", SqlDbType.VarChar, 15).Value = langue_parle;
    insertStudentCommand.Parameters.Add("@nombre_denfants", SqlDbType.Int).Value = nombre_denfants;
    insertStudentCommand.Parameters.Add("@sexe_detudiant", SqlDbType.Char, 1).Value = sexe_detudiant;
    insertStudentCommand.Parameters.Add("@program_pk", SqlDbType.Int).Value = program_pk;
    insertStudentCommand.Parameters.Add("@Numero_detudiant", SqlDbType.Int).Value = Numero_detudiant;

    numberOfRowsInserted = insertStudentCommand.ExecuteNonQuery();

    connection.Close();

    return numberOfRowsInserted;
}

Can anyone have a look at this problem please? I used try and catch block as well, it's absolutely useless in this case.

Thanks.

Answer 1

You should use ExecuteScalar instead of ExecuteNonQuery in your c# code

And use SELECT instead of return in your sql code