Get Async Key State : Key Event « Event « C# / C Sharp

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C# / C Sharp » Event » Key EventScreenshots 
Get Async Key State
Get Async Key State


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;

public class Form1 : Form
{
   [DllImport("User32.dll")]
   private static extern short GetAsyncKeyStateSystem.Windows.Forms.Keys vKey)
  private System.Windows.Forms.TextBox textBox1;
  private System.Windows.Forms.Label lbl;
  private System.Windows.Forms.Button cmdAsyncState;

  public Form1() {
        InitializeComponent();
  }

  private void Form1_KeyPress(object sender, KeyPressEventArgs e)
  {
    e.Handled = true;
  }

  private void Form1_KeyDown(object sender, KeyEventArgs e)
  {
    lbl.Text = "Key Down: " + e.KeyValue.ToString();
    lbl.Text += "\nKey Code: " + e.KeyCode.ToString();
    lbl.Text += "\nKey Data: " + e.KeyData.ToString();

    if ((e.Modifiers & Keys.Shift== Keys.Shift)
    {
      lbl.Text += "\n" "Shift was held down.";
    }

    if ((e.Modifiers & Keys.Control== Keys.Control)
    {
      lbl.Text += "\n" "Control was held down.";
    }
    if (e.Alt)
    {
      lbl.Text += "\n" "Alt was held down.";
    }
  }

  private void cmdAsyncState_Click(object sender, EventArgs e)
  {
    int state = Convert.ToInt32(GetAsyncKeyState(Keys.A).ToString());
    switch (state)
    {
      case 0:
        lbl.Text = "A has not been pressed since the last call.";
        break;
      case 1:
        lbl.Text = "A is not currently pressed, but has been pressed since the last call.";
          break;
      case -32767:
        lbl.Text = "A is currently pressed.";
        break;
    }
  }

  private void InitializeComponent()
  {
    this.textBox1 = new System.Windows.Forms.TextBox();
    this.lbl = new System.Windows.Forms.Label();
    this.cmdAsyncState = new System.Windows.Forms.Button();
    this.SuspendLayout();
    // 
    // textBox1
    // 
    this.textBox1.Location = new System.Drawing.Point(3636);
    this.textBox1.Name = "textBox1";
    this.textBox1.Size = new System.Drawing.Size(20521);
    this.textBox1.TabIndex = 0;
    this.textBox1.Text = "<Text will never appear here>";
    // 
    // lbl
    // 
    this.lbl.AutoSize = true;
    this.lbl.Location = new System.Drawing.Point(3577);
    this.lbl.Name = "lbl";
    this.lbl.Size = new System.Drawing.Size(00);
    this.lbl.TabIndex = 1;
    // 
    // cmdAsyncState
    // 
    this.cmdAsyncState.Location = new System.Drawing.Point(36202);
    this.cmdAsyncState.Name = "cmdAsyncState";
    this.cmdAsyncState.Size = new System.Drawing.Size(14124);
    this.cmdAsyncState.TabIndex = 2;
    this.cmdAsyncState.Text = "GetAsyncState() for \"A\"";
    this.cmdAsyncState.Click += new System.EventHandler(this.cmdAsyncState_Click);
    // 
    // Form1
    // 
    this.AutoScaleDimensions = new System.Drawing.SizeF(6F13F);
    this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
    this.ClientSize = new System.Drawing.Size(292266);
    this.Controls.Add(this.cmdAsyncState);
    this.Controls.Add(this.lbl);
    this.Controls.Add(this.textBox1);
    this.Font = new System.Drawing.Font("Tahoma"8.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
    this.KeyPreview = true;
    this.Name = "Form1";
    this.Text = "KeyTest";
    this.KeyPress += new System.Windows.Forms.KeyPressEventHandler(this.Form1_KeyPress);
    this.KeyDown += new System.Windows.Forms.KeyEventHandler(this.Form1_KeyDown);
    this.ResumeLayout(false);
    this.PerformLayout();

  }


  [STAThread]
  static void Main()
  {
    Application.EnableVisualStyles();
    Application.Run(new Form1());
  }

}


           
       
Related examples in the same category
1.Event system explained in detail
2.Close Form with Pressing X key
3.Check KeyCode from KeyEventArgs
4.Shift key pressedShift key pressed
5.Control Key pressedControl Key pressed
6.Alt key pressedAlt key pressed
7.Get Key action informationGet Key action information
8.Displaying information about the key the user pressedDisplaying information about the key the user pressed
9.Displays a key pressed by the userDisplays a key pressed by the user
10.Full screen and KeyEvent and MouseEvent
11.Key PressKey Press
12.Key Timer Key Timer
13.Keyboard SampleKeyboard Sample
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