Perform some functions on a listbox when i click in htmlbutton to avoid postback.

[Abeeez]

I want to perform some functions on a ListBox when I click an HTML button but I to avoid postback to minimise the server round trips....

protected void Assign_Button_Click(object sender, EventArgs e)
        {
            Button clickedButton = sender as Button;
            if (clickedButton == null)
            {
                return;
            }

            if (clickedButton == Add_Button)
            {
                if (Availableroles_ListBox.SelectedItem != null)
                {
                    AssignedRoles_ListBox.Items.Add(Availableroles_ListBox.SelectedItem.ToString());
                    Availableroles_ListBox.Items.Remove(Availableroles_ListBox.SelectedItem.ToString());
                }
            }
            else if (clickedButton == AddAll_Button)
            {
                foreach (ListItem vv in Availableroles_ListBox.Items)
                {
                    AssignedRoles_ListBox.Items.Add(vv.ToString());
                }
                Availableroles_ListBox.Items.Clear();
            }
            else if (clickedButton == Remove_Button)
            {
                if (AssignedRoles_ListBox.SelectedItem != null)
                {
                    Availableroles_ListBox.Items.Add(AssignedRoles_ListBox.SelectedItem.ToString());
                    AssignedRoles_ListBox.Items.Remove(AssignedRoles_ListBox.SelectedItem.ToString());
                }
            }
            else if (clickedButton == RemoveAll_Button)
            {
                foreach (ListItem vv in AssignedRoles_ListBox.Items)
                {
                    Availableroles_ListBox.Items.Add(vv.ToString());
                }
                AssignedRoles_ListBox.Items.Clear();
            }
         
        }

[mzmishra]

try to use javascript functions

[Frinavale]

Looking over your code, it is going to be very tricky to do this using JavaScript. There is a way, but it isn't straightforward and requires some tricky stuff so that your page requests don't get caught up in ASP.NET Page Validation errors.

I recommend that you allow the postbacks to the server. You could consider using an UpdatePanel which makes use of Ajax (asynchronous requests/postbacks) so that the process is less noticeable to the end user.

-Frinny