出错代码：

public bool Delete_List(int cID)        {            StringBuilder strSql = new StringBuilder();            strSql.Append("delete from Emp");            strSql.Append(" where C_Id = @C_Id");            SqlParameter[] parameters = {                                        new SqlParameter("@C_Id",SqlDbType.Int,4)};            parameters[0].Value = cID;            int rows = Helper.SQLHelper.ExcuteSQL(strSql.ToString());            if (rows > 0)            {                return true;            }            else            {                return false;            }        }

出错原因：

没有在执行sql语句的ExcuteSQL函数中申明标量变量

修改方法： int rows = Helper.SQLHelper.ExcuteSQL(strSql.ToString(),parameters);

将ExcuteSQL函数改为:

/// 
        /// 执行SQL语句，返回受影响的记录数        /// 
        /// SQL语句        ///         /// 
     
      受影响的行数
             public static int ExcuteSQL(string SQLString, params SqlParameter[] cmdParms)        {            using (SqlConnection connection = new SqlConnection(GetConnectionString()))//连接数据库            {                using (SqlCommand cmd = new SqlCommand())                {                    try                    {                        PrepareCommand(cmd, connection, null, SQLString, cmdParms);//关联SQL语句                        int rows = cmd.ExecuteNonQuery();                        cmd.Parameters.Clear();                        return rows;                    }                    catch (System.Data.SqlClient.SqlException e)                    {                        throw e;                    }                }            }        }