如何在ASP.NET Web表单中使用Ajax更新ListView中的值

Question

I'm using a listview and ajax in an asp.net web form. In part of that form, I display comments, which readers can rate, either positive or negative. This value isn't updated unless the page is refreshed, is there a way to update the value without the need of refreshing the page?

<asp:ScriptManager ID="ScriptManager" runat="server" EnablePageMethods="true">
    </asp:ScriptManager>
        <asp:UpdatePanel ID="UpdatePanel" runat="server">
            <ContentTemplate>
                <asp:ListView ID="ListView1" runat="server" OnItemCommand="ListView1_ItemCommand">
                    <ItemTemplate>
                        <div class="row comm_info_bar ">
                            <div class="col-md-5 RightDisplay"><%# Eval("name") %></div>
                            <div class="col-md-5 comm_info_date"><%# Eval("date") %></div>

                            <asp:LinkButton ID="negBtn" class="glyphicon glyphicon-minus voteCommentIcon voteContNeg text-danger smallGlyph" runat="server" CommandName="negative" CommandArgument='<%#Eval("id")%>' />

                            <asp:Label ID="lblnegative" name="lblnegative" class=" voteNumNeg" runat="server" Text='<%# DataBinder.Eval(Container.DataItem, "negative") %>'></asp:Label>

                            <asp:LinkButton ID="posBtn" class="glyphicon glyphicon-plus voteCommentIcon voteContNeg text-success smallGlyph" runat="server" CommandName="positive" CommandArgument='<%#Eval("id")%>' />
                            <asp:Label ID="lblpositive" class="voteNumPos" runat="server" Text='<%# DataBinder.Eval(Container.DataItem, "positive") %>'></asp:Label>

                        </div>
                        <div class="row">
                            <div class="col-md-12 comments"><%# Eval("text") %></div>
                        </div>
                    </ItemTemplate>
                </asp:ListView>
            </ContentTemplate>
        </asp:UpdatePanel>

and in code:

static List<Int64> commentsUser = new List<long>();
protected void ListView1_ItemCommand(object sender, ListViewCommandEventArgs e)
{
    string name = e.Item.DataItemIndex.ToString();
    long commentId = Convert.ToInt64(e.CommandArgument);
    ArticleCommentsDataClass ArticleComment = new ArticleCommentsDataClass();

    if (e.CommandName == "positive")
    {
        if (!searchcomments(commentId))
        {
            ArticleComment.Comments_positive(commentId);
            commentsUser.Add(commentId);
        }
    }
    else
    {
        if (!searchcomments(commentId))
        {
            ArticleComment.Comments_negative(commentId);
            commentsUser.Add(commentId);
        }
    }
}

Is there anyone who has an idea on how to do this?

Answer 1

This sounds like you are binding (reading the data of your grid) before executing the command. Since the command changes the data, you should rebind the grid or update it in any other way.

Check out this article that talks about when each event is raised