Event Handling with Atlas Client Controls
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In this conclusion to a three-part series on Atlas programming, you'll learn about text fields, handling control events, and more. This article is excerpted from chapter four of the book
Programming Atlas, written by Christian Wenz (O'Reilly, 2006; ISBN: 0596526725). Copyright © 2006 O'Reilly Media, Inc. All rights reserved. Used with permission from the publisher. Available from booksellers or direct from O'Reilly Media.
Text Fields
A single-line text box is represented in HTML using <input type="text">. This element can also be monitored and controlled using the Atlas library and the appropriate class for it, Sys.UI.TextBox. The functionality provided by Atlas covers keyboard event handling and, of course, both read and write access for the text of the element itself. The methods for the latter task areget_text()andset_text(). Example 4-7 outputs the data entered into the text field, using the same polling approach as in the preceding example (setInterval()) to periodically copy the contents of the text box to an AtlasLabelcontrol.
Example 4-7. Using an Atlas TextBox control
ControlTextBox.aspx
<%@ Page Language="C#" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server">
<title>Atlas</title>
<script language="JavaScript" type="text/javascript">
function pageLoad() {
window.setInterval(
function() {
var label = new Sys.UI.Label($("Label1"));
var textbox = new Sys.UI.TextBox($("TextBox1"));
label.set_text(textbox.get_text());
},
1000);
}
</script>
</head>
<body>
<form id="form1" runat="server">
<atlas:ScriptManager runat="server">
</atlas:ScriptManager>
<div>
<input type="text" id="TextBox1" /><br />
Entered value: <label id="Label1"></label>
</div>
</form>
</body>
</html>
Figure 4-7 shows the result.
Figure 4-7. The text in the text box appears in the label
Single-line text fields (<input type="text">), multiline text fields (<textarea>), and password fields (<input type="password">) have one thing in common: from a JavaScript point of view, they are controlled in the same way. Thevalueproperty provides read and write access to the contents of the field. Therefore, you can useSys.UI.TextBoxfor all three kinds of form fields.
Next: Base Methods >>
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 This article is excerpted from chapter four of the book Programming Atlas, written by Christian Wenz (O'Reilly, 2006; ISBN: 0596526725). Check it out today at your favorite bookstore. Buy this book now.
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