C# 存储过程重复返回-1

Question

我在 SQL Server 上反复测试这个#blankety-blank# 存储过程，它返回 0 或行数，但在 C# 中我总是得到 -1。我一直在调试这个 #blank# 的东西好几个小时，而且总是 -1。

这是存储过程代码。

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 

---

这是一个C#代码

---

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;
}

有人可以看看这个问题吗？我也使用了 try 和 catch block ，在这种情况下它绝对没用。

谢谢。

Answer 1

您应该在 C# 代码中使用 ExecuteScalar 而不是 ExecuteNonQuery

并在你的 sql 代码中使用 SELECT 而不是 return