Challenges making a simple UI in a C# program... guidance much appreciated

Taliska · July 2023

In brief: made a C# program that fills a TreeView control with info parsed from a file and displays it with PanelManager.DisplayControl(treeView... - works wonderfully (IMHO) - and employs treeView.DrawMode = TreeViewDrawMode.OwnerDrawText and DrawNode += new DrawTreeNodeEventHandler(DrawNode) to make it render nicely.

Now I decide that I need to add buttons so that I can reload the file and redisplay it ... as well as do other things. So I make some buttons using PanelManager.StackWpfElement(loadButton...... and when I click the button, it makes another Panel with a TreeView control...

Try as I might, I can't seem how to figure out how to re-use or delete/recreate a TreeView on its own panel so that there is a single "TreeView panel" after subsequent requests to reload. I am hesitant to recode the TreeView using a wpf control due the the time invested so far, and the challenges that I have overcome with that .. especially if the outcome is going to be bleak.

Many thanks in advance.
(Yet another fan on LINQPad)

JoeAlbahari · July 2023

The StackWpfElement method is a convenient shortcut that when called repeatedly, adds WPF controls to a stack panel. It works only with WPF controls, so if you need to include a WinForms control, you will need to first wrap it in a WindowsFormsHost.

Note that you don't have to use StackWpfElement - you can instead create your own containing panel and dump it. This can be either WinForms or WPF. For example, the following displays a TreeView and buttons using WinForms:

var tv = new TreeView { Dock = DockStyle.Fill };
PopulateNodes();

int fontHeight = SystemFonts.DefaultFont.Height;
var buttonsPanel = new Panel { Dock = DockStyle.Bottom, Height = fontHeight * 3, Padding = new Padding (fontHeight / 3) };
var button = new Button { Text = "Update Nodes", AutoSize = true, Dock = DockStyle.Left };
button.Click += (sender, args) => PopulateNodes();
buttonsPanel.Controls.Add (button);

var mainPanel = new Panel();
mainPanel.Controls.Add (buttonsPanel);
mainPanel.Controls.Add (tv);
mainPanel.Dump();

void PopulateNodes()
{
    tv.Nodes.Clear();   
    tv.Nodes.Add ("Now").Nodes.Add (DateTime.Now.ToString());
    tv.ExpandAll();
}

If you prefer to use WPF buttons instead of WinForms buttons (while using a WinForms TreeView), make buttonsPanel a System.Windows.Forms.Integration.ElementHost instead of a Panel - then you can assign a WPF control to its Child property.

Challenges making a simple UI in a C# program... guidance much appreciated

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