C#

string s = Console.ReadLine();
if (s == "")
    {
    continue;
    }
i = s[0];

ConsoleKeyInfo cki;
cki = Console.ReadKey(true);
i = (int) cki.Key;

1). Add a TextBox control to your form and also add a Button control.<br />
<br />
2). Now double-click the button control and the Button_Click event handler appears.<br />
<br />
3).Add the code given below to the Button_Click event handler:<br />
<br />
<pre>private void button1_Click(object sender, EventArgs e)
        {
            if (textBox1.Text == "YourCDkeyHere")
            {
                  //Steps to perform if the CDkey is correctly entered
            }
            else
            {
                  //Steps to perform if the CDkey is entered incorrectly
            }
        }
</pre><br />
<br />
<br />
So, here you are my dear fellow student. <br />
<br />
Wish you a very happy programming,<br />
Rajdeep.NET :-D