CODEWITHSUNDEEP
c#.netdata-structurestreetraversal
Justin
Justin

Reputation: 6549

How to approach this tree traversal

It has been a while since I have had to do tree traversal and would like some input. Here is a sample tree:

tree

The tree is my ASP.NET page. This page is made from 2 master pages and the content page. What I want to do is find the control that is my 2nd master page's primary content and then place all the controls inside in a flat data structure such as a list.

So given that the Orange node is the 2nd master page's primary ContentPlaceHolder, I would like to store all those in the blue ellipse in my list. I have already created some code to return me all child, grandchild, etc of a control in a collection with this:

private IEnumerable<Control> GetChildControls(Control parentControl)
{
    foreach (Control control in parentControl.Controls)
    {
        yield return control;
        foreach(Control grandchild in GetChildControls(control))
        {
            yield return grandchild;
        }
    }
}

But I am a bit stuck on how to filter this tree to a node and it's children. If it helps, the orange node should be the following:

<asp:Content ID="SystemMasterMainContentPlaceHolder" runat="server" ContentPlaceHolderID="MainContentPlaceholder">

Upvotes: 4

Views: 433

Answers (1)

voithos
voithos

Reputation: 70552

You could basically use a combination of the method you already have, and a GetChildById() method.

private Control GetChildById(string controlId, Control parent)
{
    return GetChildControls(parent).First(c => c.ID == controlId);
}

This re-uses the tree traversal that is done by GetChildControls. Note that it will throw an exception if the control is not found - if you don't want that, use FirstOrDefault instead of First.

You could potentially use it like so:

GetChildControls(GetChildById("SystemMasterMainContentPlaceHolder", Page));

Upvotes: 2

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