刷新后展开ViewTree

Question

I have a viewtree that's databound to an xml document, when the document is saved I call refresh on the datacontext and the ViewTree collapses, I really want the viewtree to not collaps, so I'm trying to write a function that unpacks it again. Here I'm trying to use the xpath of the xml elements to reach the treeviewitems, however I can only get the root object, I suspect that's because 'ContainerFromItem' requires them to be visibly there rather than logically there? But I don't know how else to do this.

This is the method that gets called after the datacontext has been refreshed

private void UnpackOpened(object sender, EventArgs e)
{
    foreach (var node in nodes)
    {
        var pathStrings = node.Path.Split('/').ToList();
        pathStrings.RemoveAll(string.IsNullOrEmpty);
        for (int i = 0; i < pathStrings.Count; i++)
        {
            pathStrings[i] = pathStrings[i].Replace("{", "").Replace("}", "");
            pathStrings[i] = pathStrings[i].Replace("[", "|").Replace("]", "");
        }

        ExpandTree(OutlineWindowInstance.TreeItems.ItemContainerGenerator, pathStrings, 0);
    }
}

This is a recursive function that's supposed to traverse all the previously open treeviewitems and expand them in the now refreshed tree.

void ExpandTree(ItemContainerGenerator itemses, List<string> treeNodes, int step)
{
    var name = treeNodes[step].Split('|')[0];
    var number = int.Parse(treeNodes[step].Split('|')[1])-1;
    var selected = itemses.Items.Cast<XmlElement>().Where(x => x.LocalName == name).ToList()[number];
    var selectedItem =((TreeViewItem) 
    //this is the line that is failing to do what I had hoped it would do
    itemses.ContainerFromItem(selected)); 
    if(selectedItem == null) return;
    selectedItem.IsExpanded = true;

    step++; 
    if (treeNodes.Count > step)
    {
        ExpandTree(selectedItem.ItemContainerGenerator, treeNodes, step);
    }
}

Answer 1

So I managed to solve this. First I have a list of all current documents, for this I created the following class, it handles all things that have to do with the nodes for the document it represents

public class OpennedDocument
{
    public string DocName { get; set; }
    public List<string> ExpandedNodes;
    public bool IsRefreshing { get; set; }

    public void AddExpandedNode(string path)
    {
        if (IsRefreshing) return; //This stops it from registering a node during automatic expansion (after a refresh)
        ExpandedNodes.RemoveAll(path.Contains);
        ExpandedNodes.Add(path);
    }

    public void RemoveExpandedNode(string path)
    {
        var index = path.LastIndexOf("/", StringComparison.Ordinal);

        if(IsRefreshing)return;
        ExpandedNodes.RemoveAll(x => x.Contains(path));

        path = path.Remove(index);
        if(!string.IsNullOrEmpty(path))
            ExpandedNodes.Add(path);
    }
}

These methods are in the general manager script and ensure that all nodes in the treeview that were open before the refresh is openned again afterwards.

private void UnpackOpened(object sender, EventArgs e)
{
    var currentDoc = Documents.SingleOrDefault(x => x.DocName == dte.ActiveDocument.FullName);
    if (currentDoc == null) return;
    currentDoc.IsRefreshing = true;

    for (var index = 0; index < currentDoc.ExpandedNodes.Count; index++)
    {
        var node = currentDoc.ExpandedNodes[index];
        var pathStrings = node.Split('/').ToList();
        pathStrings.RemoveAll(string.IsNullOrEmpty);
        for (int i = 0; i < pathStrings.Count; i++)
        {
            pathStrings[i] = pathStrings[i].Replace("{", "").Replace("}", "");
            pathStrings[i] = pathStrings[i].Replace("[", "|").Replace("]", "");
        }

        ExpandTree(OutlineWindowInstance.TreeItems.ItemContainerGenerator, pathStrings, 0,
            OutlineWindowInstance.TreeItems);
    }

    currentDoc.IsRefreshing = false;
}

void ExpandTree(ItemContainerGenerator itemses, List<string> treeNodes, int step, ItemsControl last)
{
    while (true)
    {
        last.UpdateLayout();
        var name = treeNodes[step].Split('|')[0];
        var number = int.Parse(treeNodes[step].Split('|')[1]) - 1;
        var selected = itemses.Items.Cast<XmlElement>().Where(x => x.LocalName == name).ToList()[number];
        var selectedItem = ((TreeViewItem) itemses.ContainerFromItem(selected));
        if (selectedItem == null) return;
        selectedItem.IsExpanded = true;

        step++;
        if (treeNodes.Count > step)
        {
            itemses = selectedItem.ItemContainerGenerator;
            last = selectedItem;
            continue;
        }
        break;
    }
}