Creating widgets with DesktopX 3 is, relatively speaking, a snap. Today I'm
going to walk you through how to create a widget. It's actually going to be a
pretty complicated one (for me anyway) but it will hopefully show you the ropes
on how to create fully featured widget.
The widget I want to create is one I've been looking for for a long while - A
disk space meter that lets the user configure which drive they are monitoring.
Step
1: Load up the DesktopX development environment.
This is the last option on the DesktopX Standard "Welcome" screen.
Once you had loaded it, you will be created with this dialog:
At this point, depending on your skill-level you're going to
either want to import an existing widget (which is what I'm going to do because
I need to have a sample in front of me) or you'll jump right in to making the
widget.
Step 2: Import existing widget or create one from scratch.
Since my widget is going to be getting the amount of disk space
available from a particular drive, I will want to look at a similar widget that
gets the amount of free memory available. There is a sample included with
DesktopX 3 that does this. So I'm going to click on the "Import a widget"
button.
If I had wanted to create from scratch, I would have clicked on
the "Desktop" tab in the builder dialog and chosen "New" object and started from
scratch.
The
widget in question is called the WM-Memory_meter widget. All it does is display
the amount of free memory. It's very simple. But the reason I need it is that I
don't personally know how to get system information like this via VB Script or
JavaScript.
So now I'm going to right-click on it and choose Edit Script.
Step 3: Write your script.
'Let's allocate the
object globally, so we don't waste time allocating it on each call
Dim objWMIService
Sub Object_OnScriptEnter
object.settimer 123, 5000
Set objWMIService = GetObject("winmgmts:\\.\root\cimv2")
Object_OnTimer123
End Sub
'Let's clean it, as a good
practice
Sub Object_OnScriptExit
Set objWMIService = nothing
End Sub
Sub Object_OnTimer123
Dim colItems
Set colItems = objWMIService.ExecQuery("Select AvailableMBytes from
Win32_PerfFormattedData_PerfOS_Memory",,48)
For Each objItem In colItems
Object.text = "Available memory: " & objItem.AvailableMBytes & " MB"
'we just really need one result here, so we exit
Exit Sub
Next
End Sub |
So there's the whole thing. When it starts, it created a timer called "123"
that gets called every 5,000ms (5 seconds). He's accessing the WMI stuff (which
I'm not that familiar with). And on the Timer, he's grabbing specific stuff
from the WMI object.
So okay, how do I use this to get % of disk space available. My answer:
Google. I am going to look for "Win32_PerfFormattedData_PerfOS_Memory"
in Google and see what other goodies are available. And I found
this page. And boy are there a lot of different things you can display. But
I find the one I want: "Win32_PerfFormattedData_PerfDisk_LogicalDisk".
But there's a bit more I need. The memory thingy in the example doesn't have
to grab from a particular drive. I need a way to get the disk space free on a
particular drive. That leads me back to Google where I start trying in searches
to with my newly found term with drive letters and such. I find
this page. It doesn't have what I have but you may find it useful for other
things. I eventually make it to
this page here. And then I find
this gold mine! Holy cow, there are so many things I could make with this
one page. Okay, one thing at a time..
I make this change in code:
Sub Object_OnTimer123
Dim colItems
Set colItems = objWMIService.ExecQuery("Select
* from
Win32_PerfFormattedData_PerfDisk_LogicalDisk where Name = 'C:'",,48)
For Each objItem In colItems
Object.text = "Available space: " & objItem.FreeMegabytes
& " MB"
Exit Sub
Next
End Sub |
But there's a whole bunch of things I could have instead of .FreeMegabytes.
That page has tons of things (including free space). If I want to display
the percentage of free space available, I'd use
PercentFreeSpace instead of
FreeMegabytes.
It took a bit to figure out that I simply had to plugin 'C:' as the name of
the drive in the query. But once I figured that out I was ready for the next
step.
Step 4: The Preferences Dialog
What sets this widget apart from others is that you can set which drive
you're monitoring the disk space for. To do that, I will need to build a
preferences dialog. So I look in the "DX Scripting Guide" that comes with
DesktopX and chapter 8 is "Widget Preferences".
There is only one simple rule with creating preferences -- they have to be
the very first thing you do in your script or else they won't be created. All I
want to do is create a simple combo box where the user selects the drive letter.
Therefore: I need to add these lines right after the Object_OnScriptEnter:
Sub Object_OnScriptEnter
Widget.AddPreference "Combolist1"
Widget.Preference("Combolist1").Type = "ComboList"
Widget.Preference("Combolist1").AddValue "C:"
Widget.Preference("Combolist1").AddValue "D:"
Widget.Preference("Combolist1").AddValue "E:"
Widget.Preference("Combolist1").AddValue "F:"
Widget.Preference("Combolist1").AddValue "G:"
Widget.Preference("Combolist1").DefaultValue = "C:"
Widget.Preference("Combolist1").Caption = "Available Drives"
Widget.Preference("Combolist1").Description = "Disk Drives"
object.settimer 123, 5000
Set objWMIService = GetObject("winmgmts:\\.\root\cimv2")
End Sub |
The current value of the combo box is known as
Widget.Preference("Combolist1").value. So I go back to that other
function where I had hard coded 'C:' and change it to:
Set colItems =
objWMIService.ExecQuery("Select *
from
Win32_PerfFormattedData_PerfDisk_LogicalDisk where Name = '" &
Widget.Preference("Combolist1").Value
&"'",,48)
|
The other thing we will want to add is to have it recheck when the user
closes the preferences dialog (after changing the drive letter). This is from
the docs.
Sub Widget_OnPreferencesChange
Object_OnTimer123
End Sub |
At this point on our screen we have:
Step 5: Export the object as a widget.
Now
it's time to export it as a widget. To do that, right click on it and choose
"Export".
If you have DesktopX Pro, you can export this as a "gadget"
which turns it into a stand-alone program you can send to anyone.
And here we go:
My widget is ready to go.
Here is the full source code:
'Let's allocate the object
globally, so we don't waste time allocating it on each call
Dim objWMIService
Dim szDrive
Sub Object_OnScriptEnter
Widget.AddPreference "Combolist1"
Widget.Preference("Combolist1").Type = "ComboList"
Widget.Preference("Combolist1").AddValue "C:"
Widget.Preference("Combolist1").AddValue "D:"
Widget.Preference("Combolist1").AddValue "E:"
Widget.Preference("Combolist1").AddValue "F:"
Widget.Preference("Combolist1").AddValue "G:"
Widget.Preference("Combolist1").DefaultValue = "C:"
Widget.Preference("Combolist1").Caption = "Available Drives"
Widget.Preference("Combolist1").Description = "Disk Drives"
'If I wasn't so lame I'd write something that would go through the
list of drives available and make sure only available drives are here
but I'm too lazy for that.
object.settimer 123,5000
Set objWMIService = GetObject("winmgmts:\\.\root\cimv2")
End Sub
Sub Object_OnScriptExit
Set objWMIService = nothing
End Sub
Sub Widget_OnPreferencesChange
Object_OnTimer123
End Sub
Sub Object_OnTimer123
Dim colItems
Set colItems = objWMIService.ExecQuery("Select * from
Win32_PerfFormattedData_PerfDisk_LogicalDisk where Name = '" &
Widget.Preference("Combolist1").Value &"'",,48)
For Each objItem In colItems
Object.text = "Available memory: " & objItem.FreeMegabytes & " MB"
'we just really need one result here, so we exit
Exit Sub
Next
End Sub |
Some other notes
A few observations worth noting. DesktopX isn't cross-platform. On a widget
enabling program such as this, this should be considered a feature not a
limitation. Because DesktopX is designed exclusively for Microsoft Windows (or
98% of the market) it is able to support all kinds of things that a cross
platform program would not. For instance, this example relied on the WMI
Service of Windows. There are tons of things of this nature that are specific to
Windows that can be created that wouldn't be practical if it were cross-platform
since different platforms have different features and limitations.
You can learn more about DesktopX 3 at
Link.
It comes in 3 forms: DesktopX Client (a run-time to make use of objects,
widgets, and desktops). DesktopX Standard which is what would be the least
you'd need for this example (and comes with Stardock's mega OS enhancement
suite, Object Desktop), or
DesktopX Pro which allows you to export these widgets as "gadgets" that can be
sent to anyone whether they have DesktopX or not.
PDF available
