Q:

C# Making it so the Enter Key behaves as if a button has been pressed

How do I code it so that when the enter key has been pressed it behaves as if a button on the existing form has been pressed?
Let's say the button on the form makes it so a display message of hello shows up
 private void buttonHello_Click(object sender, EventArgs e)
{
    MessageBox.Show("Hello");
}

How do I make it so when the enter key is pressed it does the same thing 
(for the life of me I can't remember and it's probably really simple and I'm being really dumb)

A:

WinForms?  If yes, select the FORM.  Now change the AcceptButton property to "buttonHello".
See Form.AcceptButton:

Gets or sets the button on the form that is clicked when the user
  presses the ENTER key.

A:

Capture the Enter key down event, like this:
private void Form1_KeyDown(object sender, KeyEventArgs e) 
{
    if (e.KeyCode == Keys.Enter){
        button.PerformClick();
    }
}

A:

In your Form properties, set AcceptButton = yourButton, That's it.

