Since SPGridView is nothing more then basic GridView with some additions maybe this link can be helpful (at least as starting point):
Handling the Enter key pressed in a GridView's row edit mode
protected void gvChild_RowDataBound(object sender, GridViewRowEventArgs e)
{
// if enter key is pressed (keycode==13) call __doPostBack on grid and with
// 1st param = gvChild.UniqueID (Gridviews UniqueID)
// 2nd param = CommandName=Update$ + CommandArgument=RowIndex
if ((e.Row.RowState == DataControlRowState.Edit) ||
(e.Row.RowState == (DataControlRowState.Edit|DataControlRowState.Alternate)))
{
e.Row.Attributes.Add("onkeypress", "javascript:if (event.keyCode == 13) {
__doPostBack('" + gvChild.UniqueID + "', 'Update$" +
e.Row.RowIndex.ToString() + "'); return false; }");
}
}
I never tested this code so here is little disclaimer:
Specific SP problems can arise on page postback. I am not sure about gvChild.UniqueID part of the sample code. I think Control.ClientID suits better.