DefaultButton - Deal with users hitting ENTER on your forms
Developers tend to assume that users will be always clicking on the buttons to submit forms. Is it a valid assumption? Unfortunately not always ... the simplest example can be quick search, a common component on many sites.
What if user simply hit ENTER instead of clicking on the button next to the text box? Because our button wasn't clicked then of course even handler for Click event won't be invoked. The problem is that users expect that hitting Enter will correctly submit the form. So what can we do?
HtmlForm and Panel
classes have a property called DefaultButton. Thanks to this property we
can address the issue. First lets check the HtmlForm.DefaultButton property,
here is how it can be used:
1: protected void Page_Load(object sender, EventArgs e) 2: {
3: Page.Form.DefaultButton = btnSearch.UniqueID;
}
That's all what is needed to make sure that
post back generated by pressing the ENTER key will be "associated"
with the button btnSearch. That is an improvement, but there is another
problem to solve, check contact us page:
This is slightly more
complex situation as here we would like to have Send button to be the default
button for HtmlForm. So what about quick search? The following piece of code
will solve it:
1: <asp:panel id="pnlSearch" runat="server" defaultbutton="btnSearchButton">
2: <asp:textbox id="txbSearchQuery" runat="server" validationgroup="search" maxlength="50" />
3: <asp:Button id="btnSearchButton" runat="server" text="Search" validationgroup="search" />
4: </asp:panel>
By surrounding the quick search controls with ASP.NET panel we can define for that group default button, different default button then the one on HtmlForm. In this simple way it's possible to define arbitrary number of small areas on the page with custom default button.
Another thing worth noticing is that defining unique validation group for
all functionally related groups of controls is considered as a good practice.
This way you can be sure that submitting one group won't trigger validation somewhere
else.
I know that those are not a life-changing features but still I find them very
useful, it's good to dust off basics like this from time to time.
