CODEWITHSUNDEEP
c#.netwinformstreeview
Horhe El Fenenado
Horhe El Fenenado

Reputation: 125

How can I set how many levels to expand TreeView nodes?

Doing this code will expand all the main nodes under root.

root
    images
    files
    docs

But I want to make that if I change it from 0 to 1 somehow to change the level so it will expand the next level.

root
   images
        myimages
   files
       myfiles
   docs
      mydocs

foreach (TreeNode tn in treeView1.Nodes)
{
    if (tn.Level == 0)
        tn.Expand();
}

I tried to add in the foreach:

if (tn.Level == 1)
    tn.Expand();

But that's not a solution.

Maybe I need foreach in foreach?

All this code is part of a method that is working under BackgroundWorker that get a list of my FTP server directories and files recursively.

So in real time while it's getting the directories and adding the nodes I want to expand the nodes level.

Upvotes: 3

Views: 4090

Answers (1)

Peter Duniho
Peter Duniho

Reputation: 70652

Because the data structure is recursive, IMHO the most appropriate way to deal with the issue is to traverse it recursively. Something like this:

void ExpandToLevel(TreeNodeCollection nodes, int level)
{
    if (level > 0)
    {
        foreach (TreeNode node in nodes)
        {
            node.Expand();
            ExpandToLevel(node.Nodes, level - 1);
        }
    }
}

You would call it like this:

ExpandToLevel(treeView1.Nodes, 1);

That would expand just the first level. Pass 2 to expand the first two levels, etc.

Upvotes: 12

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