ASP.NET checkbox value when postback inside of an repeater

Question

I have a ASP Repeater which contains a list of tags and I'd like to see which one of the tag was selected (checked).

Like:

<HeaderTemplate>
        <ul class="tags-list">
    </HeaderTemplate>
    <ItemTemplate>
        <asp:CheckBox ID="tag" runat="server" AutoPostBack="true" Text='' />
    </ItemTemplate>
    <FooterTemplate>
        </ul>
    </FooterTemplate>
</asp:Repeater>

The problem that I face is that

protected override void InitializeControls(Telerik.Sitefinity.Web.UI.GenericContainer container, Telerik.Sitefinity.Web.UI.ContentUI.Contracts.IContentViewDefinition definition)

method is fired before and:

    void tagList_ItemDataBound(object sender, RepeaterItemEventArgs e)
    {
        if (e.Item.ItemType == ListItemType.AlternatingItem || e.Item.ItemType == ListItemType.Item)
        {
            var item = e.Item.DataItem as Taxon;
            var checkbox = e.Item.FindControl("tag") as CheckBox;
            checkbox.Text = item.Title;
            checkbox.CheckedChanged += new EventHandler(this.checkbox_Changed);

        }
    }

gets fired everytime before my callback method:

protected void checkbox_Changed(object sender, EventArgs e)
{
    CheckBox tagCheckbox = (CheckBox)sender;

    if (tagCheckbox.Checked)
    {

    }
}

Can anyone guide me what would be the best practice to get the state of the checkbox(es)?

tagList_ItemDataBound will get fired if you databind your repeater in page_load without a !ispostback — Emre, May 24 '13 at 20:18
@Emre: Ok, thanks! But how do I get the checkbox state? Placing the condition for databinding will make tagList.Items.Count == 0. — el.severo, May 24 '13 at 20:24
do you have to set eventhandler in itemdatabound? why dont u use `OnCheckedChanged="checkbox_Changed"` in your checkbox? — Emre, May 24 '13 at 20:30
@Emre: I'm sorry but I think I didn't understood what you mean. The eventhandler its set programatically in `tagList_ItemDataBound` — el.severo, May 24 '13 at 20:36
@Emre: Because if I add `OnCheckedChanged="checkbox_Changed"` then the repeater doesn't gets rendered anymore.. I don't know why... — el.severo, May 24 '13 at 20:41
let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/30595/discussion-between-el-severo-and-emre) — el.severo, May 24 '13 at 20:42

score 1 · Accepted Answer · answered Jul 31 '13 at 16:20

could you try defining the "CheckedChanged" method inline with the checkbox control inside the repeater:

<asp:CheckBox ID="tag" runat="server" AutoPostBack="true" Text='' CheckedChanged="checkbox_Changed" />

Then you don't have to worry about binding the handler it in code behind. If you're not getting the correct state of the checkbox, also make sure that you have "EnableViewState" on the page properties.

I hope this is helpful, let me know if I've misunderstood the question

score 0 · Answer 2 · answered Jun 21 '16 at 15:33

I have quite dirty solution. My problem was to fire a postback of checkbox in a repeater but i also need the ID of the record. The best way to archive the ID is using ValidationGroup attribute:

<asp:CheckBox ValidationGroup='<%# DataBinder.Eval(Container.DataItem,"id") %>' ID="YOUR_ID" runat="server" AutoPostBack="true" OnCheckedChanged="checkbox_Changed" />

and in code behind:

CheckBox theCheckBox = (CheckBox)sender; 
int id = Convert.ToInt16(theCheckBox.ValidationGroup);

if someone has the same needs can use this solution.

ASP.NET checkbox value when postback inside of an repeater

2 Answers2