Private Declare Auto Function FindWindow Lib "user32" ( ByVal lpClassName As String, ByVal lpWindowName As String) As IntPtr

    'abd.hWnd = FindWindow("Shell_TrayWnd", "") 'Tasbar Handle

        ABD.hWnd = FindWindow("Shell_TrayWnd", "")

    static extern System.IntPtr FindWindow(string lpClassName, string lpWindowName);

    static extern System.IntPtr FindWindowEx(System.IntPtr hwndParent, System.IntPtr hwndChildAfter,

        FindWindowEx(FindWindow("Shell_TrayWnd", null), System.IntPtr.Zero, "TrayNotifyWnd", null);

    int FindWindow(String^ lpClassName, String^ lpWindowName);

    int FindWindowEx(int hwndParent, int hwndChildAfter,

    int hWnd=FindWindowEx(FindWindow("Shell_TrayWnd", nullptr), 0, "TrayNotifyWnd", nullptr);

IntPtr hwnd = FindWindowByCaption((IntPtr)null, "Untitled - Notepad");

        // This is different from FindWindow() in that the code below allows partial matches

static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

Private Shared Function FindWindow(ByVal lpClassName As String, ByVal lpWindowName As String) As IntPtr

    <DllImport("user32.dll", EntryPoint:="FindWindow", SetLastError:=True, CharSet:=CharSet.Auto)> _

Private Shared Function FindWindowByClass(ByVal lpClassName As String, ByVal zero As IntPtr) As IntPtr

    <DllImport("user32.dll", EntryPoint:="FindWindow", SetLastError:=True, CharSet:=CharSet.Auto)> _

Private Shared Function FindWindowByCaption(ByVal zero As IntPtr, ByVal lpWindowName As String) As IntPtr

The FindWindow function retrieves the handle to the top-level window whose class name and window name match the specified strings. This function does not search child windows.

Works hand-in-hand with FindWindowEx

*If lpClassName is NULL FindWindow will search for the window by the lpWindowName (window's title) only. This is useful if the class of a particular window is variable.

        public static int FindWindow(string windowName, bool wait)

            int hWnd = FindWindow(null, windowName);

                hWnd = FindWindow(null, windowName);

            int hWnd = FindWindow(windowName, wait);

ParenthWnd = FindWindow(lpszParentClass,lpszParentWindow);

     hWnd = FindWindowEx(ParenthWnd,hWnd,lpszClass,"");

ParenthWnd = FindWindow(lpszParentClass, lpszParentWindow)

    hWnd = FindWindowEx(ParenthWnd, hWnd, lpszClass, "")

static extern IntPtr FindWindowA(string lpClassName, string lpWindowName);

Declare Function FindWindowA Lib "user32.dll" (lpClassName As String, lpWindowName As String) As Long

    static extern IntPtr FindWindowA(string lpClassName, string lpWindowName);

    var handle = FindWindowA(null, "Untitled - Notepad");

public static extern IntPtr FindWindowEx(IntPtr parentHandle, IntPtr hWndChildAfter, string className,  string windowTitle);

Private Shared Function FindWindowEx(ByVal parentHandle As IntPtr, _

    childHandle = FindWindowEx(

    childHandle = FindWindowEx(windowHandle,IntPtr.Zero,"WorkerW",IntPtr.Zero);

        childHandle = FindWindowEx(childHandle,IntPtr.Zero,"ReBarWindow32",IntPtr.Zero);

            childHandle = FindWindowEx(childHandle, IntPtr.Zero, "ComboBoxEx32", IntPtr.Zero);

                childHandle = FindWindowEx(childHandle, IntPtr.Zero, "ComboBox", IntPtr.Zero);

                    childHandle = FindWindowEx(childHandle, IntPtr.Zero, "Edit", IntPtr.Zero);

Referrel URL : http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui/windowsuserinterface/windowing/windows/windowreference/windowfunctions/findwindowex.asp

Here is an alternative Managed API to FindWindow, The article also describes a way to CloseWindow of another process like notepad, not sure if there is such thing in Win32 API, but at least you can do it in .NET! Here is the article:

dim notepadHwnd as intptr = FindWindow("Notepad", "Untitled - Notepad")

areahwnd = FindWindowEx(mainhwnd, intptr.zero, "Edit", vbnullstring)

console.writeline("Area hwnd using findwindowex: " & clng(areahwnd))

' Area hwnd using findwindowex: 5249450

IntPtr hWnd = FindWindow("WindowClass", "WindowName");

Dim hwndMain as IntPtr = FindWindowEx(intptr.Zero,intptr.Zero,vbNullString,"My Window Title") 'Get the Window Handle

IntPtr hWnd = FindWindow("WindowClass", "WindowName");

Dim hwndMain as IntPtr = FindWindowEx(intptr.Zero,intptr.Zero,vbNullString,"My Window Title") 'Get the Window Handle

        public static extern IntPtr FindWindow( string sClsName , string sWndName );

            IntPtr Hwnd = FindWindow( null , "Form1" );

Use FindWindow and SetForegroundWindow to direct input to the desired window.

  SetForegroundWindow (FindWindow('Untitled - Notepad'))

var hWnd = IntPtr.Zero; //use FindWindowEx etc...

    'Note: this example also uses API calls to FindWindow, GetDlgItemText, and SetActiveWindow.

    theDialogBoxHandle = FindWindow(theDialogBoxClassName, theDialogBoxTitle)

            int hWnd = FindWindow(windowName, wait);

        // THE FOLLOWING METHOD REFERENCES THE FindWindowAPI

        public static int FindWindow(string windowName, bool wait)

            int hWnd = FindWindow(null, windowName);

                hWnd = FindWindow(null, windowName);

Here is an alternative Managed API to FindWindow, The article also describes a way to CloseWindow of another process like notepad, not sure if there is such thing in Win32 API, but at least you can do it in .NET! Here is the article:

    /*SetParent(FindWindow(vbnullstring,"notepad.exe"),me.handle)

    hWnd = FindWindowExW(IntPtr.Zero, IntPtr.Zero, Nothing, "Untitled - Notepad")

[DllImport("coredll.dll", EntryPoint="FindWindowW", SetLastError=true)]

private static extern IntPtr FindWindowCE(string lpClassName, string lpWindowName);

Public Declare Function FindWindow Lib "Coredll" Alias "FindWindowW" (ByVal lpClassName As String, ByVal lpWindowName As String) As IntPtr

        handle = FindWindowCE("HHTaskBar", null);

        handle = FindWindowCE("HHTaskBar", null);

        handle = FindWindowW("HHTaskBar", null);

        handle = FindWindowW("HHTaskBar", null);