Find and Close the window using WIN API

This article explains how to find and close the window using Win API.

Find the Window

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

FindWindow(string lpClassName,string lpWindowName)

Finding ClassName and WindowName using Spy++

Spy++ (SPYXX.EXE) is a Win32-based utility that gives you a graphical view of the system's processes, threads, windows, and window messages.With the Window Finder Tool you can find the properties of a selected window.

Step 1 : Arrange your windows so that Spy++ and the subject window are visible.

Step 2: From the Spy menu, choose Find Window to open the Find Window dialog box.

Step 3:  Drag the Finder Tool to the desired window. As you drag the tool, window details display in the dialog box. (Handle,Caption(Window Name),Class Name)

Example for closing Notepad

//Declartion

[DllImport("user32.dll")]

public static extern int FindWindow(string lpClassName,string lpWindowName);

DllImport("user32.dll")]

Public static extern int SendMessage(int hWnd,uint Msg,int wParam,int lParam);

public const int WM_SYSCOMMAND = 0x0112;

public const int SC_CLOSE = 0xF060;

private void button1_Click(object sender, EventArgs e)

{

    // retrieve the handler of the window

    int iHandle = FindWindow("Notepad", "Untitled - Notepad");

    if (iHandle > 0)

    {

        // close the window using API

        SendMessage(iHandle, WM_SYSCOMMAND, SC_CLOSE, 0);

    }
}

Closing google window

private void button2_Click(object sender, EventArgs e)

{

    //closing google window

    int googleHandle = FindWindow("IEFrame", "Google - Microsoft Internet Explorer provided by Cognizant");

    if (googleHandle > 0)

    {

        // close the window using API

        SendMessage(googleHandle, WM_SYSCOMMAND, SC_CLOSE, 0);

    }
}