I've got a problem in a C# windows program, I’m working with listboxes to let the user choose a value. The problem is that I use a database query to populate the listbox, like this code:

SqlCommand cmd2 = Conn.CreateCommand();

cmd2.CommandText = "SELECT * FROM " + table_Project_Relaties + " WHERE ProjectNr = '" + textBoxOffertenummer.Text + "'";

while (rdr2.Read())

{

// Get the values from the datareader and put them in the listbox

string name = rdr2.GetString(rdr2.GetOrdinal("cmp_name"));

string number = rdr2.GetValue(rdr2.GetOrdinal("cmp_wwn")).ToString();

listBox1.Items.Add(name).ToString();

}

The problem is that in the listbox the user is seeing the names (witch he can select off course) but I want to use the number in the rest of the program. I want to do another database query with this number value.

Is there any solution to get the number of the selected name of the listbox, maybe there is some “hidden�property possible?

Regards,

Frank

struct MyListItem
{
private string mName;
private int mNumber;

public string Name
{
get { return mName; }
set { mName = value; }
}

public int Number
{
get { return mNumber; }
set { mNumber = value; }
}
}

private void Form1_Load(object sender, EventArgs e)
{
listBox1.BeginUpdate();
listBox1.DisplayMember = "Name";
listBox1.ValueMember = "id";
for (int i = 0; i <= 10; i++)
{
MyListItem item = new MyListItem();
item.Name = "Item" + i.ToString("00");
item.Number = i;
listBox1.Items.Add(item);
}
listBox1.EndUpdate();
}

private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{
MyListItem item = (MyListItem)listBox1.SelectedItem;
MessageBox.Show(item.Number.ToString());
}

Hope this answers your question,

Tomas F

Hi,

Iit seems no hidden property in listbox useful for item specific information(it's there for treectrl and listrctrl).

Anyways for the current problem, we can maintain a parellel array or list (need to be taken care of inserting,removing whenever these operations done on list box),so that u can access the element of this array or list based list box .selected index and u can use the number.

Hope this will work out for ur problem.

Thanx,

Ch.T.Gopi Kumar.

There is no need for a parallel array.

When you add an item to a ListBox, you are actually adding a ListItem object. The ListItem type has a Value property you can use to store a string.

The ListBox.Items.Add method will take either a string or a ListItem object.

So Fdv99 you could do this:

listBox1.Items.Add(new ListItem(name, number));

This works because your number variable is actually a string!

struct MyListItem
{
private string mName;
private int mNumber;

public string Name
{
get { return mName; }
set { mName = value; }
}

public int Number
{
get { return mNumber; }
set { mNumber = value; }
}
}

private void Form1_Load(object sender, EventArgs e)
{
listBox1.BeginUpdate();
listBox1.DisplayMember = "Name";
listBox1.ValueMember = "id";
for (int i = 0; i <= 10; i++)
{
MyListItem item = new MyListItem();
item.Name = "Item" + i.ToString("00");
item.Number = i;
listBox1.Items.Add(item);
}
listBox1.EndUpdate();
}

private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
{
MyListItem item = (MyListItem)listBox1.SelectedItem;
MessageBox.Show(item.Number.ToString());
}

Hope this answers your question,

Tomas F

Note: System.Windows.Forms doesn't have a ListItem class, it's fromthe System.Web.UI.WebControls namespace. So you would have to import WebControls if you wanted to use it, which makes no sense if you are programming for windows.

On the other hand, if you are programming asp.net, you should of course use the ListItem class that already exists, rather than "re-inventing the wheel".