A Win32 API instance class (Code collection)

See others recentlyCodeA good function class, which is a Win32 API instance class, which includes: the sameProgramDo not start multiple times; obtain any form; restore form status; set form focus, etc.

This class is very practical. Share it with you:

1 /// Summary Description for processutils.
2 Public   Static   Class Processutils
3 {
4 Private   Static Mutex =   Null ;
5
6 /// Determine if the current process is already running
7 Public   Static   Bool Thisprocessisalreadyrunning ()
8 {
9 // Only want to call this method once, at startup.
10 Debug. Assert (mutex =   Null );
11
12 // Creatednew needs to be false in. NET 2.0, otherwise, if another instance
13 // This program is running, the mutex constructor will block, and then throw
14 // An exception if the other instance is shut down.
15 Bool Creatednew =   False ;
16
17 Mutex =   New Mutex ( False , Application. productname, Out Creatednew );
18
19 Debug. Assert (mutex ! =   Null );
20
21 Return   ! Creatednew;
22 }
23
24 [Dllimport ( " User32.dll " , Setlasterror =   True )]
25 Static   Extern Intptr findwindow ( String Lpclassname, String Lpwindowname );
26
27 [Dllimport ( " User32.dll " )]
28 [ Return : Financialas (unmanagedtype. bool)]
29 Static   Extern   Bool Setforegroundwindow (intptr hwnd );
30
31 [Dllimport ( " User32.dll " )]
32 Static   Extern   Bool Isiconic (intptr hwnd );
33
34 [Dllimport ( " User32.dll " )]
35 Static   Extern   Bool Showwindow (intptr hwnd, Int Ncmdshow );
36
37 Const   Int Sw_restore =   9 ;
38
39 [Dllimport ( " User32.dll " )]
40 Static   Extern Intptr getlastactivepopup (intptr hwnd );
41
42 [Dllimport ( " User32.dll " )]
43 Static   Extern   Bool Iswindowenabled (intptr hwnd );
44
45 /// Set focus to the previous instance of the specified program.
46 Public   Static   Void Setfocustopreviousinstance ( String Windowcaption)
47 {
48 // Look for previous instance of this program.
49 Intptr hwnd = Findwindow ( Null , Windowcaption );
50
51 // If a previous instance of this program was found...
52 If (Hwnd ! =   Null )
53 {
54 // Is it displaying a popup window?
55 Intptr hpopupwnd = Getlastactivepopup (hwnd );
56
57 // If so, set focus to the popup window. Otherwise set focus
58 // To the program's main window.
59 If (Hpopupwnd ! =   Null   && Iswindowenabled (hpopupwnd ))
60 {
61 Hwnd = Hpopupwnd;
62 }
63
64 Setforegroundwindow (hwnd );
65
66 // If program is minimized, restore it.
67 If (Isiconic (hwnd ))
68 {
69 Showwindow (hwnd, sw_restore );
70 }
71 }
72 }
73 }