Question

怎么读取DataTable某一列的值？然后用c#代码判断是否有重复数据？linq还是怎么做呢？

Answer 1

public static void cs()
        {
           
            System.Data.DataTable dt = new System.Data.DataTable();
            dt.Rows.Add("");
            var quer = from tb in dt.AsEnumerable()
                                        group tb by tb.Field<string>("xx") into x
                                        select new{ 
                                            a=x.Key,
                                            b=x
                                        };
            foreach(var c in quer)
            {
                int i = 0;
                foreach(var d in c.b)
                {
                    i++;
                }
                if(i>1)
                {
                    //有重复
                }
            }
            for (int i = 0; i < dt.Rows.Count;i++ )
            {
                var qu = from tb in dt.AsEnumerable()
                         where tb.Field<string>("xx") == dt.Rows[i]["xx"].ToString()
                         select tb;
                if (qu.Count() > 1)
                {
                    //有重复
                }
            }
        }

两种方法 看你喜欢哪种

Answer 2

               

            

DataTable dt = new DataTable(); 
var q  = from item in dt.AsEnumerable()      
  select item.Field<string>("").Distinct();  
  if (q.Count() < dt.Rows.Count)        
  {                
  //有重复             
  }