Question

之前：

Name    Class   Ability
Boy1      A1    Sing
Boy2      A1    Sing
Boy3      A2    Sing
Girl1     A2    Sing
Girl2     A2    Dance

之后：

Name                Class   Ability
Boy1,Boy2             A1    Sing
Boy3,Girl1,Girl2      A1    Sing,Dance

如何对表进行分组？我用过：DataTable dt = GetDataTable（）; //获取数据 dt.AsEnumerable（）.... //我不知道如何继续。请帮助我

Answer 1

var result = dt.AsEnumerable()
     .GroupBy(d => d.Field<string>("Class"))
     .Select(g => new
     {
         Name = string.Join(",", 
            g.Select(gn => gn.Field<string>("Name")).Distinct()),
         Class = g.Key,
         Teacher = string.Join(",", 
            g.Select(gt => gt.Field<string>("Ability")).Distinct())
     });

注意：如果直接使用Linq而不是DataTable，这会容易得多。

Answer 2

我为样本创建了一个虚拟数据

        DataTable dtNew, dt = new DataTable();
        dt.Columns.Add("Id", typeof(string));
        dt.Columns.Add("Category",typeof(string));
        dt.Columns.Add("Type",typeof(string));
        dtNew = dt.Clone();


        dt.Rows.Add("323021", "Doors", "900");
        dt.Rows.Add("323022", "Doors", "900");
        dt.Rows.Add("323023", "Doors", "1000");
        dt.Rows.Add("323024", "Doors", "1000");

        dt.Rows.Add("323025", "Walls", "200");
        dt.Rows.Add("323026", "Walls", "200");
        dt.Rows.Add("323027", "Walls", "200");
        dt.Rows.Add("323028", "Walls", "200");

        dt.Rows.Add("323026", "Columns", "300x300");
        dt.Rows.Add("323027", "Columns", "300x300");
        dt.Rows.Add("323028", "Columns", "500x500");

此方案的解决方案

        //Case 1: Category and Type
        var caretoryTypeResult = (from b in dt.AsEnumerable()
                              group b by new
                              {
                                  Category = b.Field<string>("Category"),
                                  Type = b.Field<string>("Type")
                              }
                                  into grpCategoryType
                                  select new
                                  {
                                      grpCategoryType.Key.Category,
                                      grpCategoryType.Key.Type,
                                      grpCategoryType
                                  }).ToList();

        caretoryTypeResult.ForEach(list => {
            var category = list.grpCategoryType.AsEnumerable().Select(m => m.Field<string>("Id")).ToList();
            dtNew.Rows.Add(string.Join(",", category), list.Category, list.Type);

        });

希望此代码有帮助

分组和合并值DataTable，C＃

2 个答案: