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

Question

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}" 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.

Answer 1

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.

Answer 2

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).

Answer 3

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.