How to detect the key that the user just pressed

Question

Dear All,

How to detect the key that the user just pressed? @Castorix31 told me to use WM_XXXX. I just want to know if the Up-Arrow or the Down-Arrow keys. Any simpler way you can suggest?

Answer 1

@BenTam-3003 , If you want to detect the key when the user pressed, Please override the ProcessCmdKey method in your Form.

public partial class Form1 : Form  
    {  
        public Form1()  
        {  
            InitializeComponent();  
        }  
        protected override bool ProcessCmdKey(ref Message msg, Keys keyData)  
        {  
            if (keyData == Keys.Up)  
            {  
                MessageBox.Show("Up Arrow key");  
            }  
            if (keyData == Keys.Down)  
            {  
                MessageBox.Show("Down Arrow key");  
            }  
            return base.ProcessCmdKey(ref msg, keyData);  
        }  
  
    }  

When you press Up-Arrow key, it will show a message box called Up Arrow key and so on the Down Arrow key.

Updated code:

   protected override bool ProcessCmdKey(ref Message msg, Keys keyData)  
        {  
            byte[] ascii = System.Text.Encoding.UTF8.GetBytes(keyData.ToString());  
            switch(ascii[0])  
            {  
                case byte m when m > 32 && m < 255:  
                    if(true)  
                    {  
                        break;  
                    }  
                case byte m when m == 13:  
  
                    break;  
                default:  
                    if (keyData == Keys.Up)  
                    {  
                        MessageBox.Show("up Arrow key");  
                      
                    }  
                    else if (keyData == Keys.Down)  
                    {  
                        MessageBox.Show("Down Arrow key");  
                          
                    }  
                    break;  
  
  
            }  
             
            return base.ProcessCmdKey(ref msg, keyData);  
        }  

Best Regards,
Jack

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