Question

I am working on a project. It does with drag and drop this is the code I have right now.

   namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void listBox1_MouseDown(object sender, MouseEventArgs e)
        {
            listBox1.DoDragDrop(listBox1.SelectedItem.ToString(), DragDropEffects.Move);
        }

        private void listBox2_DragEnter(object sender, DragEventArgs e)
        {
            e.Effect = e.AllowedEffect;
        }

        private void listBox2_DragDrop(object sender, DragEventArgs e)
        {
            listBox2.Items.Add(e.Data.GetData(DataFormats.Text));
            listBox1.Items.Remove(listBox1.SelectedItem.ToString());
        }

It lets you add to the second list box but I am trying to get it where you can also move the item back to first listbox if you want to. Do I repeat the code for the second list box as I did for the first one or is there a line of code I could just add.Also how can you tell if your program is “unbreakable”. Thanks.

Answer 1

For the main question of implementing drag & drop: yes, you would need to create handlers for listbox1 and listbox2 that mirror the functionality you already have:

• A MouseDown event handler for listBox2
• A DragEnter handler for listBox1
• A DragDrop handler for listBox1.

Also you’d need to make sure you assign these handlers to be used for their respective events in the form designer.