CODEWITHSUNDEEP
c#asp.netwebforms
pghtech
pghtech

Reputation: 3702

How can I traverse controls in a user control to find a certain control?

ASP.NET 2.0 Web forms

So how can you iterate through all the controls in user control and find a certain type of control and append a event to it?

I have a similar question How do I add a event to an ASP.NET control when the page loads? that deals with adding an event - but this is different if I wanted to find a control.

SCENARIO

The control is a custom control:

<asp:Repeater runat="server" ID="options" OnItemDataBound="options_OnItemDataBound">
<HeaderTemplate>
    <table border="0" cellpadding="0" cellspacing="0" width="100%">
        <tr>
</HeaderTemplate>
<ItemTemplate>
            <td>
                <span>
                    <asp:Label runat="server" ID="optionName">
                    </asp:Label>
                    <asp:DropDownList runat="server" ID="optionValues" CssClass="PartOption">
                    </asp:DropDownList>
                </span>
            </td>
</ItemTemplate>
<FooterTemplate>
        </tr>
    </table>
</FooterTemplate>
</asp:Repeater>

The custom control declaration on the user control:

<td><def:CustomControl id="somePartOptions" runat="server"></td>

In the code behind of the user control, I tried the following in the Page_Load event:

    foreach(Control control in partOptions.Controls) {
            FindDropDownControl(control);
}

    protected void FindDropDownControl(Control controlContainer) {
        bool isRepeater = false;
        if (controlContainer is Repeater) {
            isRepeater = true;
        }

        if (controlContainer.HasControls()) {
            foreach (Control subControl in controlContainer.Controls) {
                FindDropDownControl(subControl);
            }
        }
    }

However, the boolean flag is always false. So what am I doing? I am eventually wanting to find the dropdownlist control inside the itemTemplate of the repeater, but I can't even find the repeater.

thanks,

Upvotes: 2

Views: 1490

Answers (1)

Marek Kwiendacz
Marek Kwiendacz

Reputation: 9834

I'm using this method to get list of control in container (on each nesting level):

    public static List<Control> GetControlsByType(Control ctl, Type type)
    {
        List<Control> controls = new List<Control>();

        foreach (Control childCtl in ctl.Controls)
        {
            if (childCtl.GetType() == type)
            {
                controls.Add(childCtl);
            }

            List<Control> childControls = GetControlsByType(childCtl, type);
            foreach (Control childControl in childControls)
            {
                controls.Add(childControl);
            }
        }

        return controls;
    }

You can use t in this way: 

List<Control> repeaters = GetControlsByType(containerControl, typeof (Repeater));

Upvotes: 2

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