C # conversion from a private void to public void [closed]

Hello everyone, I wondered how I can convert this code to public void . Visual Studio reports an error in the and variable.

Error message: "The name 'and' does not exist in the current context"

I just made ctrl+c and ctrl+v of:

private void TextDisplay_KeyPress(object sender, KeyPressEventArgs e) 

To:

public void Detect() 

Below the body of my method:

if (e.KeyChar == 49 || e.KeyChar == 50 || e.KeyChar == 51 || e.KeyChar == 52 || e.KeyChar == 53 || e.KeyChar == 54 || e.KeyChar == 55 || e.KeyChar == 56 || e.KeyChar == 57 || e.KeyChar == 58)
        {
            TextDisplay.Text = TextDisplay.Text + e.KeyChar.ToString();
        }

        //Detetor da tecla Equal
        if (e.KeyChar == 61)
        {
            Equal();
        }

        //Detetor da tecla Multi
        if (e.KeyChar == 42)
        {
            Multi();
        }

        //Detetor da tecla Plus
        if (e.KeyChar == 43)
        {
            Plus();
        }

        //Detetor da tecla Divisão
        if (e.KeyChar == 47)
        {
            Divisão();
        }

        //Detetor da tecla  less
        if (e.KeyChar == 45)
        {
            Less();
        }

        //DetetoR da tecla backspace
        if (e.KeyChar == 8)
        {
            if (TextDisplay.Text == "")
            {
                System.Media.SystemSounds.Beep.Play();
            }
            else
            {
                if (TextDisplay.Text.Length == 1)
                {
                    TextDisplay.Text = "";
                }
                else
                {
                    TextDisplay.Text = TextDisplay.Text.Substring(0, TextDisplay.Text.Length - 1);
                }
            }
        }

        //Detetor da tecla enter
        if (e.KeyChar == 13)
        {
            Equal();
        }

        //Detetor da tecla Esc
        if (e.KeyChar == 27)
        {
            Clear();
        }