How do I Reset the Values in My ASP.NET Fields?

The current form is here. It is not complete, and only a couple options will work.

Select "Image CD" and then any resolution and click "Add to Order." The order will be recorded on the server-side, but on the client-side I need to reset the product drop-down to "{select}"开发者_如何学C so that the user will know that they need to select another product. This is consistant with the idea that the sub-selections disappear.

I don't know whether I should be using ASP postback or standard form submittal, and most of the fields need to be reset when the user adds an item to the order.

I'd use Response.Redirect(Request.RawUrl) method to reset the form data from the server side.

A little explanation: this is PRG design pattern

Used to help avoid certain duplicate form submissions and allow user agents to behave more intuitively with bookmarks and the refresh button.

A workaround for this question: necessary data may be stored in Session for example. This means we getting the data with the first POST, putting it to the storage, performing redirect and getting it back.

In the pageload event on the form, you need to add something simalar to this:

if (IsPostBack)
{
   //Proccess the order here

   ProductOption.SelectedIndex = 0;
}

That will allow you to process the order, but then start over the order form.

The simplest means would be a recursive function that forks on the type of control

private void ResetControls( Control control )
{
    if ( control == null)
        return;

    var textbox = control As TextBox;
    if ( textbox != null )
        textbox.Text = string.Empty;

    var dropdownlist = control as DropDownList;
    if ( dropdownlist != null )
        dropdownlist.SelectedIndex = 0; // or -1

    ...

    foreach( var childControl in controlControls )
        ResetControls( childControl );
}

You would this call this function in your Load event by passing this. (This is presuming you want to reset more than a single control or small list of controls).