ASP.NET - Triggering asyncpostback with LinkButton inside ListView which is inside UpdatePanel

问题

Ok my first post and i hope the title makes sense.

I have an updatepanel, and inside it resides a fileupload control with a button to trigger an upload. Beneath that i have a ListView which is databinded in the behind file with a list of files that is uploaded. The updatepanel has a "PostBackTrigger" pointed to the upload button.

All of this works just as it should. For each item that is listed, there is a linkbutton which deletes that specific file. That also works as it should BUT here is the thing: It does not trigger a postback and i tried numerous methods after searching the web and not to mention stackoverflow for answers. I tried a lot but nothing really happens even if what looks like the best solution is implemented.

The ascx file (yes its a usercontrol if that matters):

<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
    <asp:Label ID="LabelUploadFile" runat="server" Text="Upload fil:"></asp:Label>
    <br />
    <asp:FileUpload ID="FileUploadDocument" runat="server" />
    <br />
    <asp:DropDownList ID="DropDownListDocumentType" runat="server"></asp:DropDownList>
    <br />
    <asp:Button ID="ButtonUploadFile" runat="server" Text="Upload fil" CssClass="nice small radius action button" onclick="ButtonUploadFile_Click" />
    <br />
    <br />
    <br />
    <asp:ListView ID="ListViewDocuments" runat="server" OnItemCommand="ListViewDocuments_ItemCommand">
        <LayoutTemplate>
            <table border="0" cellpadding="1">
                <tr>
                    <th align="left">Type</th>
                    <th align="left">Dokument</th>
                    <th></th>
                </tr>
                <tr id="itemPlaceholder" runat="server"></tr>
            </table>
        </LayoutTemplate>
        <ItemTemplate>
            <tr>
                <td><asp:Label runat="server" ID="lblName"><%#Eval("Type") %></asp:Label></td>
                <td><asp:Label runat="server" ID="lblType"><%#Eval("Dokument") %></asp:Label></td>
                <td><asp:LinkButton ID="DeleteButton" OnClientClick="return confirm('Slet dokument?');" CommandName="Delete" CommandArgument='<%# Eval("id")%>' runat="server" Text="Slet"></asp:LinkButton></td>
            </tr>
        </ItemTemplate>
        <EmptyDataTemplate>
            <tr>
                <td>&nbsp;</td>
                <td>Du har ikke uploadet filer endnu.</td>
                <td>&nbsp;</td>
            </tr>
        </EmptyDataTemplate>
    </asp:ListView>
</ContentTemplate>
<Triggers>
    <asp:PostBackTrigger ControlID="ButtonUploadFile" />
    <asp:AsyncPostBackTrigger ControlID="ListViewDocuments" EventName="ItemCommand" />
</Triggers>

(Note the asyncpostbacktrigger is just another solution i tried out which i have not removed. Also a scriptmanager is present, it is just not represented in the above code)

The ListViewDocuments_ItemCommand from the behind file:

protected void ListViewDocuments_ItemCommand(object sender, ListViewCommandEventArgs e)
    {
        if (e.CommandName == "Delete")
        {
            //Send the file's ID to the data layer for deletion
            _talentDataAccess.DeleteTalentFileByFileId(Convert.ToInt32(e.CommandArgument));
            //Rebind the listveiw with a new list of files.
            _fillFileList();
        }
    }

So like i said, technically everything works, but in short the linkbutton does not refresh the updatepanel.

If there is any questions or need for other code snippets, i will respondt promptly.

Thank you in advance.

回答1:

It's possible that the CommandName="Delete" is raising the events ItemDeleted and ItemDeleting and not ItemCommand. Although I have to say if this was the case then I would expect the page to crash due to the absence of those events (see MSDN for more details).

That said when I have used the Delete (or Edit) word as a command I've found problems. So I would try the following

Change the name of the command to something like CommandName="ItemDelete". Does the ListViewDocuments_ItemCommand fire now
Also - to see if it is the update panel causing problems I would temporarily remove it until you are convinced that the item command fires as you want.

Hope it helps some

来源：https://stackoverflow.com/questions/11327047/asp-net-triggering-asyncpostback-with-linkbutton-inside-listview-which-is-insi

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ASP.NET

listview

updatepanel

linkbutton