Sample code sharing for C # simulation Printscreen and Alt+printscreen capturing screen pictures

C # simulates Printscreen and Alt+printscreen capturing screen pictures

Keybd_event API

function function: This function synthesizes a keystroke event. The system can use this synthetic keystroke event to generate a wm_keyup or WM_KEYDOWN message, and the keyboard driver's interrupt handler calls the Keybd_event function. In Windows NT, the function has already been replaced with SendInput.

function prototype; VOID keybd_event (BYTE bvk,byte bscan,dword dwflags,dword dwextralnfo);

Parameters:

BVK: Defines a virtual key code. The key code value must be between 1~254.
Bscan: Defines the hardware scan code for this key.
DwFlags: Defines a set of flags for each aspect of a function operation. The application can set the flag bit using the combination of some of the predefined constants below.
Keyeventf_extendedkey: If this value is specified, a prefix byte with a value of Oxeo (224) is preceded by the scan code.
Keyeventf_keyup: If the value is specified, the key is freed, and if the value is not specified, the key is pressed.
Dwextralnfo: Defines the additional 32-bit value associated with the keystroke.
Return value: The function has no return value.

Full code:

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;namespace PrintScreen{Public            Partial class Form1:form {[DllImport ("User32.dll")] static extern void keybd_event ( BYTE bvk,//virtual key value byte bscan,//hardware scan code UINT dwflags,//action ID IntPtr dwextrainfo//with keyboard        Auxiliary information for action correlation);        <summary>///Analog Print Screen Keyboard messages, capturing full-size images. </summary> public void Printscreen () {keybd_event ((byte) 0x2c, 0, 0x0, IntPtr.Zero);//d             Own application.doevents ();         Keybd_event ((byte) 0x2c, 0, 0x2, IntPtr.Zero);//up application.doevents ();        }///<summary>///Analog ALT Print Screen Keyboard message, capturing the current window picture. </summary> public void Altprintscreen () {keybd_event((byte) keys.menu, 0, 0x0, IntPtr.Zero);            Keybd_event ((byte) 0x2c, 0, 0x0, IntPtr.Zero);//down application.doevents ();            Application.doevents ();            Keybd_event ((byte) 0x2c, 0, 0x2, IntPtr.Zero);//up keybd_event ((byte) keys.menu, 0, 0x2, IntPtr.Zero);            Application.doevents ();        Application.doevents ();        } public Form1 () {InitializeComponent (); private void Form1_Load (object sender, EventArgs e) {}///<summary>//from clipboard             Take pictures///</summary>//<returns></returns> private Bitmap getscreenimage () {            IDataObject newobject = null;            Bitmap newbitmap = null;                try {application.doevents ();                NewObject = Clipboard.getdataobject (); if (Clipboard.containsimage ()) {Newbitmap = (Bitmap) (ClipboArd. GetImage ().                Clone ());            } return Newbitmap; } catch (Exception ex) {Console.WriteLine (ex.                Message);            return null; }} private void Button1_Click (object sender, EventArgs e) {button1.            Enabled = false;            pictureBox1.Image = null;            Printscreen ();            pictureBox1.Image = Getscreenimage (); Button1.            Enabled = true;        Application.doevents (); The private void button2_click (object sender, EventArgs e) {button2.            Enabled = false;            pictureBox1.Image = null;            Altprintscreen ();            pictureBox1.Image = Getscreenimage (); Button2.            Enabled = true;        Application.doevents (); }    }}

Operating effect:

Legacy issues:

Printscreen does not have a task problem, but the first time to use Altprintscreen is always unable to get the correct picture, do not know why! I hope the expert passed the guidance twos, younger brother greatly appreciated!