[C #] how to activate a window

Using system;
Using system. Collections. Generic;
Using system. componentmodel;
Using system. Data;
Using system. drawing;
Using system. text;
Using system. Windows. forms;
Using system. runtime. interopservices;
Using Microsoft. Win32;
Using system. diagnostics;

Namespace activeexternalappwindowtest
{

Public partial class form1: Form
{< br> [dllimport ("user32.dll")]
Private Static extern bool
setforegroundwindow (intptr hwnd );
[dllimport ("user32.dll")]
Private Static extern bool showwindowasync (intptr hwnd, int ncmdshow);
[dllimport ("user32.dll")]
Private Static extern bool isiconic (intptr hwnd);
// message function
[dllimport ("user32.dll", entrypoint = "postmessagea")]
Public static extern bool postmessage (intptr hwnd, int MSG, int wparam, int lparam);

[Dllimport ("user32.dll")]
Public static extern intptr findwindow (string strclassname, string strwindowname );
[Dllimportattribute ("user32.dll")]
Public static extern int sendmessage (intptr hwnd, int MSG, int wparam, int lparam );

Public const int wm_syscommand = 0x0112;
Public const int SC _maximize = 0xf030;

Public form1 ()
{
Initializecomponent ();
}

Private void button#click (Object sender, eventargs E)
{
Process [] processes = process. getprocessesbyname ("CSI ");

If (processes. length> 0)
{
Intptr hwnd = processes [0]. main1_whandle;

// If (isiconic (hwnd ))
// Showwindowasync (hwnd, 9); // 9 indicates the sw_restore flag, indicating to restore the form
Sendmessage (hwnd, wm_syscommand, SC _maximize, 0 );
Setforegroundwindow (hwnd );
}

}
}
}