C # simulate PrintScreen and Alt + PrintScreen to capture screen images,

C # simulate PrintScreen and Alt + PrintScreen to capture screen images,

C # simulate PrintScreen and Alt + PrintScreen to capture screen images

Keybd_event API function: This function is used to synthesize a key event. The system can use this synthetic key event to generate the WM_KEYUP or WM_KEYDOWN message. The interrupt handler of the keyboard driver calls the keybd_event function. In Windows NT, this function has been replaced by SendInput. Function prototype; VOID keybd_event (BYTE bVk, BYTE bScan, DWORD dwFlags, DWORD dwExtralnfo); parameter: bVk: defines a virtual key code. The key value must be 1 ~ In the range of 254.
BScan: The hardware scan code that defines the key.
DwFlags: defines a flag set for all aspects of function operations. The application can use a combination of the following predefined constants to set the flag.
KEYEVENTF_EXTENDEDKEY: if this value is specified, the first value of the scan code is the prefix byte of OXEO (224.
KEYEVENTF_KEYUP: if this value is specified, the key is released. If this value is not specified, the key is pressed.
DwExtralnfo: defines the 32-bit value associated with the strike key.
Return Value: this function has no return value. Complete 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 // auxiliary code associated with keyboard actions Add information); // <summary> // simulate the Print Screen Keyboard Message to capture a full Screen image. /// </Summary> public void PrintScreen () {keybd_event (byte) 0x2c, 0, 0x0, IntPtr. zero); // down Application. doEvents (); keybd_event (byte) 0x2c, 0, 0x2, IntPtr. zero); // up Application. doEvents () ;}//< summary> /// simulate the Alt Print Screen Keyboard Message to capture the current window image. /// </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> /// obtain an image from the clipboard /// </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 button#click (object sender, EventArgs e) {button1.Enabled = false; pictureBox1.Image = null; PrintScreen (); pictureBox1.Image = GetScreenImage (); button1.Enabled = true; Application. doEvents ();} private void button2_Click (object sender, EventArgs e) {button2.Enabled = false; Enabled = null; AltPrintScreen (); pictureBox1.Image = GetScreenImage (); button2.Enabled = true; Application. doEvents ();}}}

Running effect:

Legacy problems:

PrintScreen has no task problems, but when using AltPrintScreen, the correct image is always not available for the first time. I don't know why! I hope you can pass by and give me some advice. I am very grateful to you!

In the C language, what is the symbol (->) and how to use it?

This is a symbol in the struct pointer. Write a program to explain it, for example:
# Include <stdio. h>
Struct STU // define a struct
{
Int num;
} Stu;
Int main ()
{
Struct STU * p; // defines a struct pointer.
P = stu; // p points to the struct variable stu.
Stu. num = 100; // attaches an initial value to the struct member num.
Printf ("% d", p-> num); // output the num value in stu
Return;
}
As you can see, the-> method is to reference the variable in the struct !!
Format: p-> struct member (such as p-> num)
The function is equivalent to stu. num or (* p). num.
I don't know. You don't understand, and don't understand call me. O (∩ _ ∩) O ~
Hope to adopt it.

In the C language, what is the symbol (->) and how to use it?

This is a symbol in the struct pointer. Write a program to explain it, for example:
# Include <stdio. h>
Struct STU // define a struct
{
Int num;
} Stu;
Int main ()
{
Struct STU * p; // defines a struct pointer.
P = stu; // p points to the struct variable stu.
Stu. num = 100; // attaches an initial value to the struct member num.
Printf ("% d", p-> num); // output the num value in stu
Return;
}
As you can see, the-> method is to reference the variable in the struct !!
Format: p-> struct member (such as p-> num)
The function is equivalent to stu. num or (* p). num.
I don't know. You don't understand, and don't understand call me. O (∩ _ ∩) O ~
Hope to adopt it.