using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows.Forms; namespace InjectionPC { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void textBox1_KeyDown(object sender, KeyEventArgs e) { if (e.KeyCode==Keys.Enter) { textBox1.Text = "1"; } } } }