Make listbox items have a different value than item text

Question

Hi,

I know this is a bad question, but google has failed me.

I want a listbox full of items. Although, each item should have a different value. So when the user selects an item and presses a button: a method will be called which will use the value the select item has.

I can not/Do not want to reveal the values to the user (e.g "Item1 (value)).

Any assistance is appreciated.

EDIT: This is NOT for asp.net. It is a windows forms application. I just thought the html example would be easy to read.

I have the inspiration from HTML:

<form>
<input type="radio" name="sex" value="Value1" /> Male
<br />
<input type="radio" name="sex" value="Value2" /> Female
</form>

This also allows me to use different values then what the user sees - if I want to.

Answer 1

items have a property called 'Tag', which you can use to store any information you want (hidden from the user)

ListViewItem myItem = new ListViewItem();
myItem.Text = "Users see this";
myItem.Tag = "Users don't see this";

(or set the appropriate properties in the property explorer)

Answer 2

You can choose what do display using the DisplayMember of the ListBox.

List<SomeData> data = new List<SomeData>();
data.Add(new SomeData() { Value = 1, Text= "Some Text"});
data.Add(new SomeData() { Value = 2, Text = "Some Other Text"});
listBox1.DisplayMember = "Text";
listBox1.DataSource = data;

When the user selects an item, you can read the value (or any other property) from the selected object:

int value = (listBox1.SelectedItem as SomeData).Value;

Update: note that DisplayMember works only with properties, not with fields, so you need to alter your class a bit:

public class SomeData
{
    public string Value { get; set; };
    public string Text { get; set; };
}

Answer 3

As stated by the 1st answer, the use of DisplayMember works whether you are using asp.net or winforms.

And to comment a bit more, it also works if you are using the rather old fashion Items.add way of adding items to a ListBox.

Just for fun, here is a simple demo of what you need (just create a new form and drop on it a ListBox and a Label):

public partial class Form1 : Form
{
    class Customer
    {
     public string FirstName { get; set; }
     public string LastName { get; set; }

     public override string ToString()
     {
      return string.Format("{0} {1}", LastName, FirstName);
     }
    }

    public Form1() { InitializeComponent(); }

    protected override void OnLoad(EventArgs e)
    {
     base.OnLoad(e);                        
     listBox1.DisplayMember = "LastName";            
     listBox1.DataSource = GetCustomers();
     //listBox1.Items.AddRange(GetCustomers().ToArray());            
    }

    private IEnumerable<Customer> GetCustomers()
    {
     return new List<Customer>()
     {
      new Customer() { FirstName = "Gustav", LastName = "MAHLER" },
      new Customer() { FirstName = "Johann Sebastian", LastName = "BACH" }
     };
    }

    private void lb_SelectedIndexChanged(object sender, EventArgs e)
    {
     label1.Text = listBox1.SelectedItem.ToString();
    }        
}

Enjoy

PS: @2nd post Tag is not available to ListBox: because it accepts an array of object, not a specific item container like ListView... but you don't need any in your case. Tag is useful when you want to carry additional data along with a specific TreeViewItem or ListViewItem for example. By the way, Tag is defined at the Control level and so exists for Button, Label, and so on... but for my part I think it is rather a bad idea to store business data in it (untyped, UI coupled...) apart from the ListView and TreeView cases for which it is rather convenient.