Creating child node in TreeView using foreach

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I have to List<string>, with the following contents (let's say):

C#

List<string> listA = new List<string>();
List<string> listB = new List<string>();

listA.Add("main1");
listA.Add("main2");
listA.Add("main3");

listB.Add("sub1");
listB.Add("sub2");
listB.Add("sub3");

Now. Here comes where I stuck:

I would like to have the following TreeView:

HTML

|
|-main1-|
|       |-sub1
|       |-sub2
|       |-sub3
|
|-main2-|
|       |-sub1
|       |-sub2
|       |-sub3
|
|-main3-|
|       |-sub1
|       |-sub2
|       |-sub3

I wanna use foreach loop for each Lists. The following code gives me error:

C#

foreach (string mains in listA)
{
    TreeNode node = new TreeNode(mains);
    
    foreach (string subs in listB)
    {
        TreeNode node2 = new TreeNode(subs);

        treeView.Nodes[mains].Nodes.Add(node2);
    }

    treeView.Nodes.Add(node);
}

The error is in the inner foreach, but dunno why... The tree hierarchy is being made as I like. Please help me correcting this loop.

Thanks

Posted 21-Sep-15 2:31am

DoomMaker79

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2 solutions

Solution 2

You could simplify this:

C#

private void makeTree(List<string> headings, List<string> items)
{
    foreach (var s0 in headings)
    {
       TreeNode newNode = new TreeNode(s0);
       treeView1.Nodes.Add(newNode);

       foreach (var s1 in items)
       {
           newNode.Nodes.Add(new TreeNode(s1));
       }
    }
}

You'd call it like this:

C#

makeTree(
    new List<string> {"one", "two", "three"},
    new List<string> {"sub1", "sub2"});

Posted 21-Sep-15 3:12am

BillWoodruff

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DoomMaker79 · Accepted Answer · 2015-09-21T02:41:00

ok, I got it finally... Wrong ordering and do not need two TreeNode. So the correct is:

C#

foreach (string mains in listA)
            {
                TreeNode node = new TreeNode(mains);
                treeView1.Nodes.Add(node);

                foreach (string subs in listB)
                {
                    node.Nodes.Add(subs);
                }

                
            }