I lot of great ideas came in the discussion about How to create a Default "Enter" Button for Forms/PostBacks.

There are a number of good solutions, here they are collected, as well as an additional one from Dino Esposito.

• Similar to my idea, add a hidden EVENTTARGET, Darrell suggests to use the ClientID:
  Page.RegisterHiddenField("__EVENTTARGET", btnSearch.ClientId) - Darrell Norton
• Jeff uses a JavaScript function and adds an onkeydown handler to the text box's attributes:
  Client-Side function:
    function AnyInput_KeyDown (e, target)
    { if ((e.which && e.which == 13) || (e.keyCode && e.keyCode == 13))
    { __doPostBack(target, ''); return false; } return true; }
  Caller: onkeydown -> "AnyInput_KeyDown(event,'btnSearch');" - Jeff Hulburt
• Brian suggests Andy Smith's DefaultButton control. 
• Gerry Heidenreich has some VB.NET code on his site that rolls the above ideas into the Page_Load.
• Phil Manijak suggests chaining events like:
  private void SearchBox_TextChanged(object sender, EventArgs e) {
  // Pass the event along, as if it were a button click.
  this.SearchButton_Click(sender, e); }
• Matt Berther has a great fix on his site that involves just adding a hidden text box with no name.
• Here's a great solution from Dino Esposito that takes the form of a Smart Text Box Server Control. PostTextBox.txt (5.57 KB)