Question

此代码有什么问题？代码工作，但它返回空gridview？如果我调试代码，我可以看到我的字符串plName包含播放器名称，但是当我将它添加到对象时它是空的？另外，我如何检查我的查询结果是否为空？我相信这不是最佳方式......

protected void Page_Load(object sender, EventArgs e)
    {
    if(!IsPostback) 
    {
        List<AllPlayers> listOfPlayers  = new List<AllPlayers>();

        string plName = "";
        string plStatus = "";

        using (PlayerEntities playerEntities = new PlayerEntities())
        {
            var query = (from pl in playerEntities.players from st in playerEntities.player_status.Where(a => a.players_key == pl.players_key).DefaultIfEmpty() 
            from pt in playerEntities.play_times.Where(b => b.players_key == pl.players_key).DefaultIfEmpty() select new { pl, st, pt }).ToList();
            foreach (var item in query)
            {
                plName = item.pl.player_name.ToString();

                try // better way check if this is NULL ?
                {
                    plName = item.st.default_times_start.ToString();
                }
                catch(Exception ex)
                {
                    ex.Message.ToString();
                }

                AllPlayers demo = new AllPlayers(plName, plStatus);

                listOfPlayers.Add(demo);
            }
        }
        GridView1.DataSource = listOfPlayers;
        GridView1.DataBind();
}
    }

ASPX：

<body>
<form id="form1" runat="server">
<div>
    <asp:GridView ID="GridView1" runat="server">
    </asp:GridView>
</div>
</form>

为什么这个gridview是空的，我怎么能更好地检查null？

0 个答案: