Question

I would like to thank contributors in advanced, I am rather stuck on this one:

I have created a List View called listView1 and when the program runs it displays data files (.txt, .doc etc) from a particular folder specified in a Tree View called treeView1. In these same folders next to the data files are icon files(.ico). I would like to assign a .ico to be displayed as the image for the .txt or .doc file that will be loaded into listView1. Both the data file and icon file have the same name just a different extension. Therefor I already have a way of matching the icon file to the data file. However, I cannot seem to find a way to programically assign the icon file as the image to be displayed for the data file in listView1. I cannot use a Image List because you can only assign images from a image list based on its image index not its name. All signs seem to point to creating a array but I cannot figure out how to assign an image in a array to a data file while I am adding it to listView1.

I hope that makes sense, thank you!

Answer 1

Once you have added your image files to an ImageList, you most certainly CAN refer to them by their name (the ImageKey property). The following code works. It is rather crude, because I have no idea how you are populating your Treeview or Listview with data. I just threw in some test data and used common means of populating Treenodes and ListViewItems.

Hope this helps. Let me know if you have questions . . .

public partial class Form1 : Form
{
    // A Class member variable to hold images, to be used by both the 
    // TreeView AND the ListView:
    ImageList _myImagelist;

    public Form1()
    {
        InitializeComponent();

        // Initialize your memeber variable:
        _myImagelist = new ImageList();

        // Add some hokey test images for this arbitrary example:
        _myImagelist.Images.Add("Image1", Properties.Resources.SomeImage);
        _myImagelist.Images.Add("Image2", Properties.Resources.AnotherImage);

        // Some crude code to populate the list with test data:
        TreeView lst = this.treeView1;
        lst.ShowPlusMinus = true;

        // Set a reference to your member variable:
        lst.ImageList = _myImagelist;

        // Now populate your tree nodes and subnodes:
        TreeNode parent;

        //A parent . . .
        parent = lst.Nodes.Add("FirstNode", "Image One", "Image1");

        //  . . . with children:
        parent.Nodes.Add("P1:S1", "Parent One Child One", "Image1");
        parent.Nodes.Add("P1:S2", "Parent One Child Two", "Image1");

        // Another parent . . .
        parent = lst.Nodes.Add("SecondNode", "Image Two", "Image2");

        // . . . More children:
        parent.Nodes.Add("P2:S1", "Parent Two Child One", "Image2");
        parent.Nodes.Add("P2:S2", "Parent Two Child Two", "Image2");
    }


    // Event handler for the AfterSelect Event:
    private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
    {
        TreeNode nd = e.Node;
        this.FillList(nd);
    }


    private void FillList(TreeNode node)
    {
        ListView lv = this.listView1;
        lv.View = View.List;

        // Set the reference to your same member variable:
        lv.SmallImageList = _myImagelist;
        lv.Items.Clear();

        foreach (TreeNode nd in node.Nodes)
        {
            // The Listview also has an override of the .Add method which accepts the image KEY as
            // an argument. The nd.ImageKey property returns a string, which the ListView item recognizes
            // as the key for an item in the referenced ImageList:
            ListViewItem newItem = new ListViewItem(nd.Text, nd.ImageKey);
            lv.Items.Add(nd.Name, nd.Text, nd.ImageKey);
        }

    }
}