protected override void OnInit(EventArgs e)
{
base.OnInit(e);
// For the onclick script to be executed in IE 6 when the users presses Enter inside the form
// the button needs to be the default button. (In Firefox it doesn't.)
if (_isDefaultButton)
{
HtmlForm parentForm = ControlUtils.GetParentForm(this, true);
if (string.IsNullOrEmpty(parentForm.DefaultButton))
{
parentForm.DefaultButton = UniqueID;
}
else
{
if (parentForm.DefaultButton != UniqueID)
{
throw new ApplicationException(string.Format("Form '{0}' contains a {1} '{2}', but the default"
+ " button has been set to '{3}'. This would prevent the onclick JavaScript from running"
+ " when the user submits the form by pressing Enter in IE.",
parentForm.ClientID, GetType().Name, UniqueID, parentForm.DefaultButton));
}
}
}
}
protected override void OnPreRender(EventArgs e)
{
base.OnPreRender(e);
if (_isDefaultButton)
{
HtmlForm parentForm = ControlUtils.GetParentForm(this, true);
if (parentForm.DefaultButton != UniqueID)
{
throw new ApplicationException(string.Format("Form '{0}' contains a {1} '{2}', which is not set"
+ " as the default button (probably because another control overwrote the DefaultButton"
+ " property). This would prevent the onclick JavaScript from running when the user submits"
+ " the form by pressing Enter in IE.", parentForm.UniqueID, GetType().Name, UniqueID));
}
}
}
protected override void OnLoad(EventArgs e)
{
base.OnLoad(e);
// If this button is the Default button process postbacks without an event target, which
// would happen if the client has JavaScript disabled.
if (Page.IsPostBack)
{
HtmlForm parentForm = ControlUtils.GetParentForm(this, false);
if (parentForm != null && !string.IsNullOrEmpty(parentForm.DefaultButton) &&
parentForm.DefaultButton == UniqueID && string.IsNullOrEmpty(Page.Request.Form[EVENT_TARGET_FIELD]))
{
OnClick(EventArgs.Empty);
}
}
}