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But this means we will need to decide
where to put it on the screen. With IDSSAPI, we can easily
use the registry to save where the windows was located the
last time it was displayed and use that position to place
the window the next time it is displayed. Doing this is
simply a matter of adding the following calls to IDSSAPI:
Private Sub Form_Load()
'place this form on the screen based on the position saved
in the registry
Me.Top = IDSS_Reg.GetSetting(irkHKEY_CURRENT_USER, "IDSSAPI_Demo",
"Top", 0)
Me.Left = IDSS_Reg.GetSetting(irkHKEY_CURRENT_USER, "IDSSAPI_Demo",
"Left", 0)
End Sub
Private Sub Form_OKClick()
IDSS_Reg.SaveSetting irkHKEY_CURRENT_USER, "IDSSAPI_Demo",
"Top", CLng(Me.Top)
IDSS_Reg.SaveSetting irkHKEY_CURRENT_USER, "IDSSAPI_Demo",
"Left", CLng(Me.Left)
App.End
End Sub
With the IDSSAPI registry functions,
the only thing you have to worry about is passing the right
parameters. In both GetSetting and SaveSetting, the first
three parameters specify what value in the registry we are
dealing with (note that IDSSAPI provides much more flexibility
than even VB6 in this aspect). The only difference between
the two functions is the fourth parameter. In SaveSetting,
the fourth parameter specifies the value to be saved. On
the other hand, GetSetting uses the fourth parameter to
specify a default value that it will return if the key does
not exist. In the sample code above, we use a default value
of 0 for both settings, therefore the first time the program
is run, the Window will be shown in the very top-left of
the screen.
Handling hardware button presses is
also extremely easy with the help of IDSSAPI. The following
lines tell the operating system to notify your form when
a specific button is pressed:
IDSS_Win.SetAppKeyWindowAssociation iakAPP1,
Me.hWnd
IDSS_Win.SetAppKeyWindowAssociation iakAPP2, Me.hWnd
IDSS_Win.SetAppKeyWindowAssociation iakAPP3, Me.hWnd
IDSS_Win.SetAppKeyWindowAssociation iakAPP4, Me.hWnd
After you've done this, the operating
system will call your form's Form_KeyPress method whenever
a hardware button is pressed - even if another program has
the focus. To handle this function call, you can use a Select…Case
statement like:
Select Case KeyAscii
'first hardware button pushed
Case IDSSAPI.iakAPP1
…
'second hardware button pushed
Case IDSSAPI.iakAPP2
…
'third hardware button pushed
Case IDSSAPI.iakAPP3
…
'fourth hardware button pushed
Case IDSSAPI.iakAPP4
…
End Select
Finally, we can use a simple Timer
control to periodically update the statistics gathered by
IDSSAPI.
'update the memory statistics
CurMem = IDSS_Mem.MemoryLoad
If CurMem > MaxMem Then
MaxMem = CurMem
ElseIf CurMem < MinMem Then
MinMem = CurMem
End If
'update the power statistics
CurPwr = IDSS_Pwr.BatteryLifePercent
If CurPwr > MaxPwr Then
MaxPwr = CurPwr
ElseIf CurPwr < MinPwr Then
MinPwr = CurPwr
End If
In conclusion, IDSSAPI is a great tool
that gives eVB users easy access to complex features. While
IDSS is actively improving the product and creating more
examples, there are a few minor
drawbacks. However, the small price is well worth the
hours of debugging and research it is likely to save you.
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