C# .NET DropDownList OnSelectedIndexChanged not firing

Question

Currently I have a dropdownlist in a asp:repeater. The dropdownlist gots two different events.

DataBinding and SelectedIndexChanged. But the SelectedIndexChanged just won't trigger not matter what.

Here's my ASP code:

<asp:UpdatePanel runat="server" UpdateMode="Conditional">
                <ContentTemplate>
                    <asp:Repeater runat="server" ID="_repArticles">
                        <ItemTemplate>
                            <tr>
                                <td>
                                    <img width="130" height="100" src='<%# Eval("ImageFilePath") %>' /> 
                                </td>
                                <td>
                                    <%# Eval("Price") %>
                                </td>
                                <td>
                                    <asp:DropDownList AutoPostBack="true" runat="server" ID="_ddlQuantity" OnDataBinding="_ddlQuantity_DataBinding" OnSelectedIndexChanged="_ddlQuantity_SelectedIndexChanged"></asp:DropDownList>
                                </td>
                                <td>
                                    <%# Eval("TotalPrice") %>
                                </td>
                                <td>
                                    <asp:LinkButton runat="server" ID="_btnRemove" OnClick="_btnRemove_Click" CssClass="close" ToolTip='<%$ Resources: Resource, Remove %>' CommandArgument='<%# Eval("ProductId") %>' ForeColor="Transparent" BackColor="Transparent"></asp:LinkButton>
                                </td>
                            </tr>
                        </ItemTemplate>
                    </asp:Repeater>
                </ContentTemplate>
            </asp:UpdatePanel>

And here's my C# code:

protected void _ddlQuantity_DataBinding(object sender, EventArgs e)
    {
        var ddl = sender as DropDownList;

        for (int i = 1; i < Convert.ToInt32(Eval("Stock")); i++)
            ddl.Items.Add(new ListItem(i.ToString(), i.ToString()));

        ddl.SelectedValue = Eval("Quantity").ToString();
    }

    protected void _ddlQuantity_SelectedIndexChanged(object sender, EventArgs e)
    {
        var ddl = sender as DropDownList;

        this.MasterPage.UpdateCartItem(Convert.ToInt32(Eval("ProductId")), Convert.ToInt32(ddl.SelectedValue));

        ddl.SelectedValue = Eval("Quantity").ToString();
    }

I start to think that you can't use both of these events, does anyone know what I am doing wrong?

Yes, the event just doesn't fire, the databinding does fire selectedindexchanged doesnt. Project is also on debug mode. — Rick, Jun 09 '14 at 15:59
try setting a asyncpostback trigger with ID and event of the dropdown — Karthik Ganesan, Jun 09 '14 at 16:04
Karthik Ganesan the dropdownlist are generated in the repeater so I can't just say ControlID="_ddlQuantity". — Rick, Jun 09 '14 at 16:07
If the postback event isn't triggering, that generally means the postback isn't happening. This implies a JavaScript error. Have you checked the console? — Daniel, Jun 09 '14 at 16:08
Make sure you aren't re-binding the DDL when you past back. That will reset the `SelectedIndexChanged` event. — D Stanley, Jun 09 '14 at 16:10
well you can try this after your databind.... 'UpdatePanel1.Update();' — Rex, Jun 09 '14 at 16:22
Not to sound stupid but are you certain you are changing the index of the drop down? — CathalMF, Jun 09 '14 at 16:23
I also found a post somewhere stating that if the SelectedValue within each index is the same it wont fire. — CathalMF, Jun 09 '14 at 16:24
Could this be your issue. http://stackoverflow.com/questions/485390/why-isnt-the-selectedindexchanged-event-firing-from-a-dropdownlist-in-a-gridvie?rq=1 — CathalMF, Jun 09 '14 at 16:31

score 0 · Answer 1 · answered Jun 09 '14 at 16:05

0

You can try changing

UpdateMode="Always"

from

UpdateMode="Conditional"

answered Jun 09 '14 at 16:05

Trikaldarshiii

11,174
16
67
95

Been suggested in the comments below the question, didn't work unfortunately. – Rick Jun 09 '14 at 16:09

score 0 · Answer 2 · answered Jun 10 '14 at 04:43

0

Well I got the solution, and it's a facepalm moment. I rebinded the repeater on the page load, forgot to set the "if (!IsPostBack)" around it.

answered Jun 10 '14 at 04:43

Rick

79
1
8

score 0 · Answer 3 · answered Jun 10 '14 at 09:26

Put Triggers in UpdatePanel and then try

<asp:UpdatePanel runat="server" UpdateMode="Conditional">
            <ContentTemplate>
                <asp:Repeater runat="server" ID="_repArticles">
                    <ItemTemplate>
                        <tr>
                            <td>
                                <img width="130" height="100" src='<%# Eval("ImageFilePath") %>' /> 
                            </td>
                            <td>
                                <%# Eval("Price") %>
                            </td>
                            <td>
                                <asp:DropDownList AutoPostBack="true" runat="server" ID="_ddlQuantity" OnDataBinding="_ddlQuantity_DataBinding" OnSelectedIndexChanged="_ddlQuantity_SelectedIndexChanged"></asp:DropDownList>
                            </td>
                            <td>
                                <%# Eval("TotalPrice") %>
                            </td>
                            <td>
                                <asp:LinkButton runat="server" ID="_btnRemove" OnClick="_btnRemove_Click" CssClass="close" ToolTip='<%$ Resources: Resource, Remove %>' CommandArgument='<%# Eval("ProductId") %>' ForeColor="Transparent" BackColor="Transparent"></asp:LinkButton>
                            </td>
                        </tr>
                    </ItemTemplate>
                </asp:Repeater>
            </ContentTemplate>
<Triggers>
            <asp:PostBackTrigger ControlID="_ddlQuantity" />
        </Triggers>
        </asp:UpdatePanel>

C# .NET DropDownList OnSelectedIndexChanged not firing

3 Answers3