Detect Enter Key C#

in your form designer class (formname.designer.cs) add this :

this.KeyPress += new System.Windows.Forms.KeyPressEventHandler(this.Login_KeyPress);

and add this code to backbone code (formname.cs):

void Login_KeyPress(object sender, KeyPressEventArgs e)
    {
        if (e.KeyChar == (char)13)
            MessageBox.Show("ENTER has been pressed!");
        else if (e.KeyChar == (char)27)
            this.Close();
    }

This is because when you press Enter TextChanged event won't fire.