Question

使用winform我试图使用下面的代码从数据库中将按类别分组的食物项目显示到radlistview中;但问题在于它显示的是主要群组，但未显示其下的项目。

  ZalaqEntities1 zlq=new ZalaqEntities1();

        List<cat> cats = zlq.cats.ToList();
        radListView1.Items.Clear();
        radListView1.Groups.Clear();
        radListView1.EnableGrouping = true;
        radListView1.ShowGroups = true;

        for (int i = 0; i < cats.Count(); i++)
        {
            radListView1.Groups.Add(new ListViewDataItemGroup());
            radListView1.Groups[i].Value = cats[i].catname;
            radListView1.Groups[i].Key = cats[i].catid;


        }

        List<fooditem> fooditems = zlq.fooditems1.ToList();
        for (int j = 0; j < fooditems.Count(); j++)
        {
            ListViewDataItem myitem = new ListViewDataItem();
            myitem.Value = fooditems[j].itemname;
            myitem.Key = fooditems[j].itemid;
           // myitem.Group = radListView1.Groups[1];
            radListView1.Items.Add(myitem);
            myitem.Group = radListView1.Groups.Where(i => i.Key == fooditems[j].catid).FirstOrDefault();
            //radListView1.Items[j].Group = radListView1.Groups[1];
        }
        radListView1.Refresh();

我正在尝试使用where条件在其类别下添加Item，以通过其Key找到正确的组。

如果我在Loop外面执行此操作，则可以在for循环中添加几个Item。但是来自数据库。

Answer 1

问题只是在Where子句中强制转换i.Key.ToString（）。

最终守则：

      ZalaqEntities1 zlq=new ZalaqEntities1();

        List<cat> cats = zlq.cats.ToList();
        radListView1.Items.Clear();
        radListView1.Groups.Clear();
        radListView1.EnableGrouping = true;
        radListView1.ShowGroups = true;

        for (int i = 0; i < cats.Count(); i++)
        {
            ListViewDataItemGroup grp = new ListViewDataItemGroup();
            grp.Value = cats[i].catname;
            grp.Key = cats[i].catid.ToString();
            radListView1.Groups.Add(grp);
            radListView1.Groups[i].Key = cats[i].catid;
         }
        radListView1.Refresh();
          List<fooditem> mfooditems = zlq.fooditems1.ToList();
        for (int j = 0; j < mfooditems.Count(); j++)
        {
            ListViewDataItem myitem = new ListViewDataItem();
            myitem.Value = mfooditems[j].itemname;
            myitem.Key = mfooditems[j].itemid;
             radListView1.Items.Add(myitem);
            radListView1.Refresh();
            radListView1.Items[j].Group = radListView1.Groups.Where(i => i.Key.ToString() == mfooditems[j].catid.ToString()).FirstOrDefault();

        }
        radListView1.Refresh();

Telerik Radlistview动态分组项目

1 个答案: