Telerik Radlistview 动态分组项目答案

【问题标题】：Telerik Radlistview dynamically grouping itemsTelerik Radlistview 动态分组项目
【发布时间】：2017-02-01 16:53:10
【问题描述】：

使用winform，我试图使用下面的代码从数据库中将分组在类别下的食物显示到radlistview中；但问题是它显示主要组但不显示其下的项目。

  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 条件将项目添加到其类别下，以通过其键找到正确的组。

如果我在 for 循环之外执行此操作，它可以添加多个 Items。但是从 for 循环非内的数据库中添加。

【问题讨论】：

标签： c# telerik

【解决方案1】：

问题只是在 Where 子句中强制转换 i.Key.ToString() ..

最终代码：

      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();

【讨论】：