Question

我有这样的公开名单：

public List<links> googleRec = new List<links>();

public class links
{
    public string url { get; set; }
    public string title { get; set; }
    public string description { get; set; }
    public int place { get; set; }
}

我在page_load（）

中设置了这些值

protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {  //googlerec get its values in page_load correctly}
 }

当我想在googlerec中使用page_load外的值时，它有0条记录

foreach (links element in googleRec)
        {

            //googlerec has no record here
     }

Answer 1

您可以在会话中存储列表

Session["googleRec"] = new List<links>();

Answer 2

您可以使用通常用于保存特定网页特定信息的ViewState。

要在ViewState活动中Page_Load()保存您的列表

ViewState["myList"] = googleRec;

从ViewState

返回列表

List<links> googleRec= (List<links>)ViewState["myList"];

如果您想了解有关ViewState的更多信息，请参阅详细链接。 https://msdn.microsoft.com/en-us/library/ms972976.aspx

Answer 3

请考虑以下示例。

代码背后：

public partial class _Default : Page
{

    public List<links> googleRec = new List<links>();

    protected void Page_Load(object sender, EventArgs e)
    {
        if(!IsPostBack)
        {
            googleRec = GetLinks();
            Session["links"] = googleRec;
        }
        else
        {
            googleRec = (List<links>)Session["links"];
        }
    }

    private List<links> GetLinks()
    {
        return new List<links>
        {
            new links {description = "new link 1", place = 1, title = "link title 1", url = "https://www.facebook.com/" },
            new links {description = "new link 2", place = 2, title = "link title 2", url = "http://www.google.pl" },
            new links {description = "new link 3", place = 3, title = "link title 3", url = "https://twitter.com/?lang=pl" },
        };
    }
}

查看：

<hr />

<div class="row">
    <div class="col-md-4">

        <% foreach (links item in googleRec) { %>

        <div>
            <%= item.title  %>
        </div>

        <% } %>
    </div>
</div>

<hr />

<asp:Button ID="sender" runat="server" Text="Do postback" />

在c＃中保留page_load（）时，我的列表丢失了它的值

3 个答案: