Intermediate 10 min read Control #11

ListBox Control

The ListBox displays a scrollable list of items. Users can select one or more items.

What is a ListBox?

A ListBox shows items in a list. Users can scroll through and select items. It's great for showing a list of options, files, or names.

Code Example

// Add items
listBox1.Items.Add("Item 1");
listBox1.Items.AddRange(new object[] { "Item 2", "Item 3" });

// Get selected item
private void btnGetSelected_Click(object sender, EventArgs e)
{
    if (listBox1.SelectedItem != null)
    {
        MessageBox.Show($"Selected: {listBox1.SelectedItem}");
    }
}

// Multi-selection
listBox1.SelectionMode = SelectionMode.MultiExtended;

// Get all selected items
private void btnGetAllSelected_Click(object sender, EventArgs e)
{
    var selected = new List<string>();
    foreach (var item in listBox1.SelectedItems)
    {
        selected.Add(item.ToString());
    }
    MessageBox.Show($"Selected: {string.Join(", ", selected)}");
}

Exercise

Task: Create a simple shopping list app.

  1. Add a ListBox with shopping items.
  2. Add a TextBox and Button to add new items.
  3. Add a Button to remove selected items.
  4. Add a Button to clear all items.
  5. Add a Label showing total items count.
Key Takeaway

ListBox is great for displaying lists. Use SelectionMode to control whether users can select one or multiple items.

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