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POC# Large Tree Iteration
 

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    <p>I have a large result set assembled in a parent/child relationship. I need to walk the tree and display the results to the user. </p> <p>I've done this before using recursion, but because my result set may be large, I want to avoid the possibility of receiving a StackOverflowException.</p> <p>I found the following <a href="http://msdn.microsoft.com/en-us/library/bb513869.aspx" rel="nofollow noreferrer">example</a> on MSDN which uses a Stack. The problem I'm having is because a stack is last-in first-out, my data doesn't appear properly. I'd like it to look like the following:</p> <pre><code> LeveL 1 Level 1.1 Level 1.1.1 Level 1.1.2 Level 1.2 Level 1.2.1 Level 1.2.2 </code></pre> <p>But it looks like:</p> <pre><code> LeveL 1 Level 1.2 Level 1.2.2 Level 1.2.1 Level 1.1 Level 1.1.2 Level 1.1.1 </code></pre> <p>Any ideas?</p> <p>Here is an example of my code. Assuming the <code>DataTable dt</code> has the following columns: ID, ParentID, and Text</p> <pre><code> private struct Item { public string Text; public int ID; public int ParentID; } private void BuildView() { Stack&lt;Item&gt; itemTree = new Stack&lt;Item&gt;(40); //Get All Parent Nodes DataView dv = new DataView(dt); dv.RowFilter = "ParentID = 0"; //Add the parent nodes to the stack foreach (DataRowView drv in dv) { Item item = new Item(); item.Text = drv["Text"].ToString(); item.ID = drv["ID"].ToString(); item.ParentID = drv["ParentID"].ToString(); itemTree.Push(item); } //Go through the stack one node at a time while (itemTree.Count &gt; 0) { Item currentItem = itemTree.Pop(); Debug.WriteLine(currentItem.Text); //Get children of current node dv.RowFilter = String.Format("ParentID = {0}", currentItem.ID); if (dv.Count &gt; 0) { //Add child nodes to the stack foreach (DataRowView drvChild in dv) { Item item = new Item(); item.Text = drvChild["Text"].ToString(); item.ID = drvChild["ID"].ToString(); item.ParentID = drvChild["ParentID"].ToString(); itemTree.Push(item); } } } } </code></pre>
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