Click on Listbox name to fill Textboxes with Username and Password

I want when click on the Name Listed on a Listbox from the database to fill Textboxes with Username and Password of particular user from SQL database.

I am able to see Names stored on the database on the listbox but when i click on the name its unable to fill the Textboxes.

Here is the code that fills the Listbox with data from database (NOTE: I am able to view a list of names on the Listbox with the code below)

 Public Sub ListBox()
    Try
        If con.State = ConnectionState.Open Then
            con.Close()

        End If
        con.Open()
        Dim cmd As SqlCommand
        cmd = con.CreateCommand()
        cmd.CommandText = "SELECT * FROM Admin"
        Dim Reader As SqlDataReader
        Reader = cmd.ExecuteReader
        While Reader.Read
            lbAdmin.Items.Add(Reader.Item("Full Name"))
        End While
    Catch ex As Exception
    End Try
End Sub

And here is the code I want to fill the Textboxes after clicking on a name in a Listbox (NOTE: Unable to fill Textboxes with code below). I really dont know where I am going wrong, please help.

Private Sub lbAdmin_SelectedIndexChanged(sender As System.Object, e As System.EventArgs) Handles lbAdmin.SelectedIndexChanged
    Try
        If con.State = ConnectionState.Open Then
            con.Close()
        End If
        con.Open()

        Dim cmd As SqlCommand
        cmd = con.CreateCommand()
        cmd.CommandText = "SELECT * FROM Admin"
        Dim Reader As SqlDataReader
        Reader = cmd.ExecuteReader
        While Reader.Read
            txtfullname.Text = Reader.GetString("Full Name")
            txtusername.Text = Reader.GetString("Username")
            txtpassword.Text = Reader.GetString("Password")
        End While
    Catch ex As Exception
    End Try
End Sub