listbox, textbox bind

[ludmann]

Can someone please tell me how to bind the listBox to a textbox?
In my code below, I have a listBox1, which is bound to a data table and displays a list of last names. I bound the selected value to email address, just because this is the primary key in the table.

Below the listbox, I have a textbox, which supposed to display all other fields in the row, that is selected in the listBox. I thought if I could get the datatable to return the id for the row, I could entered that in the text box section like, dt_shared.Rows[returnedid].ToString()

Is there a default id for a datarow in a datatable, and if yes how can I get it? And how can I then bind the listbox to the textbox?

If not how can I bind the listbox to the textbox?

listBox1.DataSource = dt_shared;
listBox1.DisplayMember = "LastName";
listBox1.ValueMember = "Email1Address";
listBox1.DataBindings.Add("SelectedValue",dt_shared,"Email1Address");


String str = "";

for(int i=0; i< dt_shared.Columns.Count; i++)
{
if(dt_shared.Rows[?].ToString() != null)
{
str = str + dt_shared.Rows[?].ToString() + "\r\n";
}

}

textBox1.Text = str;

Thank you

Marika