回发后无法还原动态转发器控件的值

Question

i use ItemCreated to create my dynamic controls. but after a post back since ItemDataBound not triggering, i cant restore my controls values with e.Item.DataItem . DataItem is null after the post back. how can i restore my values..? my code is like below

    protected void rptV_ItemCreated(object sender, RepeaterItemEventArgs e)
    {
        if (e.Item.ItemType == ListItemType.AlternatingItem || e.Item.ItemType == ListItemType.Item)
        {
            if (** condition 01 **)
            {
                if (** condition 01 **)
                {
                    RadioButton rdoBtn = new RadioButton();
                    rdoBtn.ID = "rbtnID";
                    rdoBtn.EnableViewState = true;
                    rdoBtn.GroupName = "GroupName";
                    rdoBtn.AutoPostBack = true;
                    rdoBtn.Attributes.Add("value", (e.Item.DataItem != null) ? DataBinder.Eval(e.Item.DataItem, "UserID").ToString() : "");
                    rdoBtn.CheckedChanged += new System.EventHandler(this.rdoBtnChecked_Changed);
                    Panel pnlRbtnSet = e.Item.FindControl("pnlSelect") as Panel;
                    pnlRbtnSet.Controls.Add(rdoBtn);
                }
                else
                {
                    CheckBox chkBox = new CheckBox();
                    chkBox.ID = "chkBxID";
                    chkBox.Checked = true;
                    chkBox.EnableViewState = true;
                    chkBox.Attributes.Add("value", (e.Item.DataItem != null) ? DataBinder.Eval(e.Item.DataItem, "UserID").ToString() : "");
                    Panel pnlChkBoxesSet = e.Item.FindControl("pnlSelect") as Panel;
                    pnlChkBoxesSet.Controls.Add(chkBox);
                }
            }
        }
    }

please help me if someone can

Answer 1

In most scenarios, dynamic controls can be substituted by static controls. By that, you avoid a lot of effort and trouble related to the dynamic creation of controls. That said, in your case you could add a MultiView to the ItemTemplate and show the View that is appropriate for the record:

<asp:Repeater ID="rpt" runat="server" OnItemDataBound="rpt_ItemDataBound">
    <ItemTemplate>
        <asp:MultiView ID="multiView" runat="server">
            <asp:View runat="server">
                <asp:RadioButton ID="radioBtn" runat="server" Text='<%# DataBinder.Eval(Container.DataItem, "Text") %>' Checked='<%# DataBinder.Eval(Container.DataItem, "Checked") %>' />
            </asp:View>
            <asp:View runat="server">
                <asp:CheckBox ID="checkBox" runat="server" Text='<%# DataBinder.Eval(Container.DataItem, "Text") %>' Checked='<%# DataBinder.Eval(Container.DataItem, "Checked") %>' />
            </asp:View>
        </asp:MultiView>
    </ItemTemplate>
</asp:Repeater>

In the samples, I use the following class for the data items:

public class Item
{
    public int Index { get; set; }
    public string Text { get; set; }
    public bool Checked { get; set; }
}

protected void Page_Load(object sender, EventArgs e)
{
    if (!Page.IsPostBack)
    {
        var data = Enumerable.Range(1, 6)
            .Select(x => new Item() { Index = x, 
                                      Text = "Item " + x.ToString(), 
                                      Checked = (x % 2) == 0 });
        rpt.DataSource = data;
        rpt.DataBind();
    }
}

In the ItemDataBound event, you set the active view according to your needs:

protected void rpt_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
    if (e.Item.ItemType == ListItemType.Item ||
        e.Item.ItemType == ListItemType.AlternatingItem)
    {
        var multiView = (MultiView)e.Item.FindControl("multiView");
        multiView.ActiveViewIndex = ((Item)e.Item.DataItem).Index % 2;
    }
}

In a PostBack you can access the static controls of the Repeater items:

protected void btn_Click(object sender, EventArgs e)
{
    var lst = new List<string>();
    foreach (RepeaterItem item in rpt.Items)
    {
        if (item.ItemType == ListItemType.Item ||
            item.ItemType == ListItemType.AlternatingItem)
        {
            var multiView = (MultiView)item.FindControl("multiView");
            if (multiView.ActiveViewIndex == 0)
            {
                var radioBtn = (RadioButton)item.FindControl("radioBtn");
                lst.Add("Radio button is " + (radioBtn.Checked ? "" : "not ") + "checked.");
            }
            else
            {
                var checkBox = (CheckBox)item.FindControl("checkBox");
                lst.Add("Check box is " + (checkBox.Checked ? "" : "not ") + "checked.");
            }
        }
    }
}

From my experience, dynamic controls should be avoided as long as possible because sooner or later they cause a lot of trouble. I hope this answer gives you an idea on how to achieve this in your scenario.

Answer 2

找到了解决方案..可以将viewstate与e.Item.ItemIndexID一起使用