Drag n Drop files into listbox but not duplicate files?

lynn osler

15y5.4k

I am building a drag and drop that will drag a file into a listbox and "tooltip" the file location. Right now, I am trying to get it so that if the file is already there, it won't add it, but give a pop up saying it is there. Here is my code.

public partial class MainWindow : Window{

public

{
InitializeComponent();
}

MainWindow()public MainWindow()private void filesDropped(object sender, DragEventArgs e)

if (e.Data.GetDataPresent(DataFormats.FileDrop))

{
string[] droppedFilePaths = e.Data.GetData(DataFormats.FileDrop, true) as string[];
foreach (string droppedFilePath in droppedFilePaths)
{

ListBoxItem fileItem = new ListBoxItem();

fileItem.Content = System.IO.Path.GetFileNameWithoutExtension(droppedFilePath);
fileItem.ToolTip = droppedFilePath;
DropListBox.Items.Add(fileItem);

}

}

8 Replies

Know the answer? Post it — somebody with the same question will find it here.

Sam Hobbs15y ago
The way I would do it is that I would create an object datasource that the list is bound to. Then I would search the datasource, not the control. All that is a bit much to learn but once you know how it makes things like this object-oriented and easier. I am however not yet familiar with WPF so I am not sure of the details of how to do it.
Dan Sullivan15y ago
Good. Now you just ou need to work out an if statmeant or something of the like to see if you found the file to be a duplicate or not, and add it accordingly. Try it yourself :).

~Dan
lynn osler15y ago
I got excited, it works, kind of. If I add a file, then go to add the same file, I get the popup menu, BUT, it still adds the file to the list.
Dan Sullivan15y ago
Hmm, if that isn't working, then you're going to need to write your own check. Something like this

foreach (ListboxItem li in DropListBox.Items)
{
if(li.ToolTip == fileItem.tooltip)
{
MessageBox.Show("It exists!");
break;
}
}
lynn osler15y ago
ok ... this is what I did... and I think by the way it looks, it SHOULD work? But it doesn't. Am I missing something?

        if (!DropListBox.Items.Contains(fileItem))
        {
                DropListBox.Items.Add(fileItem);
        }
        else
        {
                MessageBox.Show("File Exists");
        }
Dan Sullivan15y ago
Thanks, that's much clearer. Try checking to see if the DropListBox.Items collection contains a ListBoxItem with the same information. I believe you can call at DropListBox.items.Contains(fileItem) to check.

If you can't, you could always iterate through the collection for an item with the same tooltip property.

~Dan
lynn osler15y ago
It didn't paste, I edited to make it right. The code works, it just will add the same file 100 times. I want to add many files, duplicating none. And I am very new to C# kind of winging this on the fly, and trying to figure out what to use to accomplish this.
Dan Sullivan15y ago
Some of your code appears to have not pasted correctly. Have you tried checking the items collection of the DropListBox for a file with the same droppedFilePath?

~Dan