C# – Setting images from icons in a TreeView

ctreeviewwinforms

I'm writing my own C#-based application launcher, and, while I get it to populate the TreeView and launch application shortcuts in it, I can't seem to figure out how to add the icons as images to the TreeView. My current code for getting the files is:

    private void homeMenu_Load(object sender, EventArgs e)
    {
        this.ShowInTaskbar = false;
        if (Directory.Exists((Directory.GetParent(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData)).FullName + "\\Roaming\\Launcher")))
        {

        }
        else
        {
            Directory.CreateDirectory(Directory.GetParent(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData)).FullName + "\\Roaming\\Launcher");
        }

        DirectoryInfo launcherFiles = new DirectoryInfo(Directory.GetParent(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData)).FullName + "\\Roaming\\Launcher");

        lstPrograms.Nodes.Add(CreatingDirectoryTreeNode(launcherFiles));

        lstPrograms.Sort();

    }

    private static TreeNode CreatingDirectoryTreeNode(DirectoryInfo directoryInfo)
    {
        var directoryNode = new TreeNode(directoryInfo.Name);

        foreach (var directory in directoryInfo.GetDirectories())
        {
            directoryNode.Nodes.Add(CreatingDirectoryTreeNode(directory));
        }

        foreach (var file in directoryInfo.GetFiles())
        {
            directoryNode.Nodes.Add(new TreeNode(file.Name));
        }

        return directoryNode;
    }

The main problem I have is adding the icon to the TreeList's ImageList to the particular node. I know I need to add:

lstPrograms.ImageList.Images.Add(Icon.ExtractAssociatedIcon());

to actually add the icon to the image list, how do I get that particular image's index, then add it to the TreeView with its relative file?

Best Answer

First, add the images as resources and define your image list:

static ImageList _imageList;
public static ImageList ImageList
{
    get
    {
        if (_imageList == null)
        {
            _imageList = new ImageList();
            _imageList.Images.Add("Applications", Properties.Resources.Image_Applications);
            _imageList.Images.Add("Application", Properties.Resources.Image_Application);
        }
        return _imageList;
    }
}

Then, set the ImageList property of the TreeView:

treeView1.ImageList = Form1.ImageList;

Then, when you create the nodes, for a specific node, use:

applicationNode.ImageKey = "Application";
applicationNode.SelectedImageKey = "Application";
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