如何使用此表中的值从数据库中删除行？

Question

So I'm learning ASP.NET and I've hit a roadblock in trying to create a webpage that connects to an sqlite database and allows for that database to be modified from the webpage. Currently the FindControl is returning NULL and I'm trying to be able to delete the row with delete button in the same row. Also the table is going to be changing sizes so I'm not sure how to make it so that the button and row are always corresponding.

Also when I look at the page in developer tools and at the table the id for the td tag for each element in the first column is in a format of id ="Repeater1_id_0" then id ="Repeater1_id_1" etc. I was testing to see if I could make the button work for the third row, but I still got null.

Here is the code for the table from the database on the webpage in a .aspx file.

<asp:Repeater ID="Repeater1" runat="server" OnItemCommand="Repeater1_ItemCommand">

            <HeaderTemplate>

                <table border="1">
                    <tr>
                        <td><b>ID</b></td>
                        <td><b>Player</b></td>
                        <td><b>Points</b></td>
                        <td><b>Steals</b></td>
                        <td><b>Blocks</b></td>
                        <td><b>Assists</b></td>
                        <td><b>MPG</b></td>
                        <td><b>Shot %</b></td>
                        <td><b>3 Point %</b></td>
                    </tr>
            </HeaderTemplate>

            <ItemTemplate>

                <tr>
                    <td runat="server"  id="id"><%# DataBinder.Eval(Container.DataItem, "id") %> </td>
                    <td><%# DataBinder.Eval(Container.DataItem, "playername") %> </td>
                    <td><%# DataBinder.Eval(Container.DataItem, "points") %> </td>
                    <td><%# DataBinder.Eval(Container.DataItem, "steals") %> </td>
                    <td><%# DataBinder.Eval(Container.DataItem, "blocks") %> </td>
                    <td><%# DataBinder.Eval(Container.DataItem, "assists") %> </td>
                    <td><%# DataBinder.Eval(Container.DataItem, "MPG") %> </td>
                    <td><%# DataBinder.Eval(Container.DataItem, "shootingpercentage") %> </td>
                    <td><%# DataBinder.Eval(Container.DataItem, "threepointpercentage") %> </td>
                    <td><asp:Button ID="btnEdit" runat="server" Text="Edit" /></td>
                    <td><asp:Button ID="btnDelete" runat="server" Text="Delete" OnClick="btnDelete_click" /></td>
                </tr>

            </ItemTemplate>

            <FooterTemplate>


            </FooterTemplate>

        </asp:Repeater>

Now here is the code for what the delete button will do when clicked on in the aspx.cs file. It doesn't work but hopefully it kind of gives an insight into what I'm trying to do.

protected void btnDelete_click(object sender, EventArgs e)
    {
        NBAPlayerRepository players = new NBAPlayerRepository();
        HtmlGenericControl playerId = (HtmlGenericControl)Page.FindControl("Repeater1_id_2");
        var id =Guid.Parse( playerId.ToString());
        players.DeleteRecord(id);

        DataTable table = players.GetAll();

        this.Repeater1.DataSource = table;
        this.Repeater1.DataBind();

    }

I'm kind of a beginner at this stuff so hopefully I haven't broken it too badly.

Answer 1

The correct way of handling button clicks within an ASP.Net Repeater control is to :

(1) Set the Button CommandName parameter appropriately, eg in your case "Delete".

(2) Handle the ItemCommand event on your Repeater control. Check the CommandName property on the event argument object. If this equals "Delete" then you can process the delete, and you can get the data (row) context by looking at the Item property of the event argument object.

As already mentioned by others FindControl only works for server controls, and in any event assuming the identifier format of repeater items is not recommended.