获取“无法找到类型或命名空间名称”，但一切似乎都可以吗？ [英] Getting “type or namespace name could not be found” but everything seems ok?

问题描述

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Data;

namespace DataTableExample
{
    class Program
    {
        static void Main(string[] args)
        {

            DataTable dt = new DataTable("Student");

            dt.Columns.Add("Id", typeof(int));
            dt.Columns.Add("Name", typeof(string));
            dt.Columns.Add("Branch", typeof(string));
            dt.Columns.Add("Age", typeof(int));
            dt.Columns.Add("SocialMarks", typeof(int));
            dt.Columns.Add("MathsMarks", typeof(int));
            dt.Columns.Add("ScienceMarks", typeof(int));
            dt.Columns.Add("TotalMarks", typeof(int));
            dt.Columns.Add("AverageMarks", typeof(decimal));


            List<Students> students = new List<Students>();//Students the type or namespace coulnt be found 

            Console.WriteLine("Please enter a number to create students and start processing");
            string[] classes = { "Semester-I", "Semester-II", "Semester-III", "Semester-IV" };
            string[] Branches = { "Computers", "Electronics", "Civil", "Mechanics" };



            Random cls = new Random();
            Random brnc = new Random();
            Random ag = new Random();
            Random marks1 = new Random();
            Random marks2 = new Random();
            Random marks3 = new Random();
            int n = int.Parse(Console.ReadLine());
            for (int i = 0; i < n; i++)
            {



                DataRow dr = dt.NewRow();
                dr["id"] = i;
                dr["Name"] = "Name" + i.ToString();
                dr["Branch"] = Branches[brnc.Next(0, 3)];
                int age = ag.Next(17, 22);
                int socialMarks = marks1.Next(50, 100);
                int mathsMarks = marks2.Next(50, 100);
                int scienceMarks = marks3.Next(50, 100);
                int totalMarks = socialMarks + mathsMarks + scienceMarks;
                dr["Age"] = age;
                dr["SocialMarks"] = socialMarks;
                dr["MathsMarks"] = mathsMarks;
                dr["ScienceMarks"] = scienceMarks;
                dr["TotalMarks"] = totalMarks;
                dr["AverageMarks"] = (float.Parse(dr["TotalMarks"].ToString()) / 3).ToString();
                dt.Rows.Add(dr);
            }
            Console.WriteLine("from data table");
            Console.WriteLine("ID | Name | Age| Branch | Socail | Science | Maths | Total Marks|Average");
            foreach (DataRow dr in dt.Rows)

            {
                Console.WriteLine(dr["Id"] + "| " + dr["Name"] + "|" + dr["Age"] + "|" + dr["Branch"] + "|" + dr["SocialMarks"] + "|" + dr["ScienceMarks"] + "|" + dr["MathsMarks"] + "|" + dr["TotalMarks"] + "|" + dr["AverageMarks"]);
            }
       

            Console.WriteLine("list the count of students agewise");
            var groupbyage = Student.GroupBy(s => s.Age).Select(lst => new { Age = lst.Key, Count = lst.Count() });
            foreach (var ags in groupbyage.OrderBy(lst => lst.Age))
            {
                Console.WriteLine("Age : " + ags.Age + " | Count: " + ags.Count);
            }

推荐答案

您似乎忘记在名称空间中添加using语句，其中包含Students类。



同时检查学生的拼写，因为班级名称通常是单数。

It seems that you forgot to add using statement for namespace in which "Students" class is present.

Also check the spelling of "Students" as the class Names are usually singular.

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