调试易

protected void Page_Load(object sender, EventArgs e)
    {
        using (SqlConnection conn = new SqlConnection(连接串)）
        {
            conn.Open();
            string str = "select 名称,count(1) as 数量 from tb group by 名称";
            DataSet ds = new DataSet();
            SqlDataAdapter da = new SqlDataAdapter(str,conn);
            da.Fill(ds,"ss");
            GridView1.DataSource = ds.Tables["ss"];
            GridView1.DataBind();
        }
    }

str = "select A,B ,count(1)  from tb group by A,B;

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;/// <summary>
///实体类
/// </summary>
public class User
{
    public User()
    {
        //
        //TODO: 在此处添加构造函数逻辑
        //
    }
    private string name;    public string Name
    {
        get { return name; }
        set { name = value; }
    }
    private string pwd;    public string Pwd
    {
        get { return pwd; }
        set { pwd = value; }
    }
    private int sum;    public int Sum
    {
        get { return sum; }
        set { sum = value; }
    }}
//集合
public List<User> GetUser()
    {
        User u1 = new User();
        u1.Name = "A1";
        u1.Pwd = "B1";
        u1.Sum = 1;        User u4 = new User();
        u1.Name = "A1";
        u1.Pwd = "B4";
        u1.Sum = 1;        User u5= new User();
        u1.Name = "A1";
        u1.Pwd = "B5";
        u1.Sum = 1;        User u2 = new User();
        u2.Name = "A2";
        u2.Pwd = "B2";
        u2.Sum = 1;
        User u3 = new User();
        u3.Name = "A2";
        u3.Pwd = "B3";
        u3.Sum = 1;
        List<User> uList = new List<User>();
        uList.Add(u1);
        uList.Add(u2);
        uList.Add(u3);
        uList.Add(u4);
        uList.Add(u5);
        return uList;
    }
//分组和countList<User> ulist = GetUser();
        var query = ulist.GroupBy(p => p.Name);//按名称分组
        foreach (var item in query)
        {
            int c = (from o in ulist where o.Name == item.Key select o).ToList().Count;//根据名称查询每个组的数量
            foreach (User val in item)
            {
                //----
            }
        }

刚才初始化集合错了
正确代码::
public List<User> GetUser()
    {
        User u1 = new User();
        u1.Name = "A1";
        u1.Pwd = "B1";
        u1.Sum = 1;        User u4 = new User();
        u4.Name = "A1";
        u4.Pwd = "B4";
        u4.Sum = 1;        User u5= new User();
        u5.Name = "A1";
        u5.Pwd = "B5";
        u5.Sum = 1;        User u2 = new User();
        u2.Name = "A2";
        u2.Pwd = "B2";
        u2.Sum = 1;
        User u3 = new User();
        u3.Name = "A2";
        u3.Pwd = "B3";
        u3.Sum = 1;
        List<User> uList = new List<User>();
        uList.Add(u1);
        uList.Add(u2);
        uList.Add(u3);
        uList.Add(u4);
        uList.Add(u5);
        return uList;
    }

List<User> ulist = GetUser();
        var query = ulist.GroupBy(p => p.Name);//按名称分组
        foreach (var item in query)
        {
            int c = (from o in ulist where o.Name == item.Key select o).ToList().Count;//根据名称查询每个组的数量
            Response.Write("第"+item.Key+"组:<br/>");
            foreach (User u in item)
            {
                Response.Write("Name:"+u.Name+"<br/>");
                Response.Write("Pwd:" + u.Pwd + "<br/>");
                Response.Write("Pwd:" +c.ToString() + "<br/>");
            }
        }

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Collections;namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            IList<Test> list = GetList();            //IEnumerable<IGrouping<string, int>> query = list.GroupBy(test => test.name+test.age, test => test.age);
            //  foreach (IGrouping<string , int> petGroup in query)
            //    {
            //        // Print the key value of the IGrouping.
            //          Console.WriteLine(petGroup.Key);
            //        // Iterate over each value in the 
            //        // IGrouping and print the value.
            //           foreach (int num in petGroup)
            //            Console.WriteLine("  {0}",num );
            //    }            //  Console.ReadLine();              bool isgo = true;              IList<Test> list2 = new List<Test>();              foreach (Test info in list)
              {                  if (ishave(info,list2))
                  {
                      continue;
                  }                  int count = 0;
                  foreach (Test info2 in list)
                  {
                      if (info.name.Equals(info2.name) && info.age == info2.age)
                      {                        
                              count = count + info2.num;                
                      }
                      else
                      {
                        
                          continue;
                      }
                  }
                  Test t1 = new Test();
                  t1.name = info.name;
                  t1.age = info.age;
                  t1.num = count;
                  list2.Add(t1);              }              foreach (Test tinfo in list2)
              {
                  Console.Write(tinfo.name+"("+tinfo.age+")："+tinfo.num);
          
                
              }
              Console.ReadLine();        }        public static bool ishave(Test info,IList<Test> list)
        { 
            bool isHave=false;
            foreach (Test t in list)
            {
                if (t.name.Equals(info.name) && t.age == info.age)
                {
                    isHave = true;
                }
            }               return isHave;
        }        public static IList<Test> GetList()
        {
            IList<Test> list = new List<Test>();            Test t1 = new Test();
            t1.name = "兔子";
            t1.age = 3;
            t1.num = 1;            Test t2 = new Test();
            t2.name = "兔子";
            t2.age = 3;
            t2.num = 1;            Test t3 = new Test();
            t3.name = "兔子";
            t3.age = 3;
            t3.num = 1;            Test t4 = new Test();
            t4.name = "猪";
            t4.age = 4;
            t4.num = 1;            Test t5 = new Test();
            t5.name = "猪";
            t5.age = 4;
            t5.num = 1;            Test t6 = new Test();
            t6.name = "猪";
            t6.age = 4;
            t6.num = 2;            Test t7 = new Test();
            t7.name = "猪";
            t7.age = 4;
            t7.num = 3;            list.Add(t1);
            list.Add(t2);
            list.Add(t3);
            list.Add(t4);
            list.Add(t5);
            list.Add(t6);
            list.Add(t7);            return list;
        }       
    }        public class Test
        {                       public string name { get; set; }            public int  age { get; set; }            public int num { get; set; }
        }
      
}