Dot Net Thoughts

In my last post I have created a simple Windows 7 Gadget for testing Regular expressions. In this post we look into the Gadget Options dialog and Gadget API, which helps to display the options dialog and save the preferences from the User. The options dialog is a nice feature used in Gadgets to manage the user preferences. It is also an HTML file. Unlike the main Gadget HTML file, which is specified in the XML Definition file, the Options HTML File is specified in the main gadget file or in the main Javascript file, generally in the gadget initialization area of your script. In the RegEx Tester example, I am using the RegEx function flags as customization options.

RegEx Tester Settings

So I have created an HTML File with 3 checkboxes and wrote a javascript function to get the user selected options, create the flags variable, and when closing the Options dialog, save the user preferences. To create the settings or options dialog, set the SettingsUI property.

System.Gadget.settingsUI = "settings.html";

After setting the SettingsUI property, the Gadget will display a Options button in the Gadget handle.

Settings Button

The Gadget API also supports various events / callback functions for the Options dialog, like SettingsClosing, SettingsClosed etc, which helps to save the Preferences and Read the preferences in the Gadget.

System.Gadget.onSettingsClosed = settingsClosed;
function settingsClosed(event) {
	//OK Button clicked.
if (event.closeAction == event.Action.commit) {
	//Load settings here.
}
}

Gadget API supports various methods to read and write settings. For writing setting we can use System.Gadget.Settings.write or System.Gadget.Settings.writeString. Both the functions will expects a key/value pair. And for reading can use System.Gadget.Settings.read or System.Gadget.Settings.readString, both of these functions take a key and return a value. If the key does not exist (for instance if it has never been written) both will return a value of undefined. Use System.Gadget.Settings.xxxxString method, if you are working with string values. All the settings are stored in Settings.ini file. And it is available in the “C:\Users\\AppData\Local\Microsoft\Windows Sidebar” location.
Saving the preferences

System.Gadget.Settings.write("RegExOptionsSaved", "true");
System.Gadget.Settings.write("RegExOption", escape(result));

And reading the Preferences 

if (System.Gadget.Settings.read("RegExOptionsSaved")) {
regExOptions = unescape(System.Gadget.Settings.read("RegExOption"));
}

RegEx Object constructor 

var re = new RegEx("Pattern","Flags");

And the Flags are

1. Global Search – g – The global search flag makes the RegExp search for a pattern throughout the string, creating an array of all occurrences it can find matching the given pattern.
2. Ignore Case – i – The ignore case flag makes a regular expression case insensitive. For international coders, note that this might not work on extended characters such as å, ü, ñ, æ.
3. Multiline Input – m – This flag makes the beginning of input (^) and end of input ($) codes also catch beginning and end of line respectively.