Passing info message to a Wicket page while using PageParameters

问题

Does Wicket somehow allow passing both of the following kinds of params in a PageParameters object? Apparently not?

• accountId which is shown in the URL (/account/<ID>)
• infoMessage parameter which is not shown in the (bookmarkable) URL

I'm currently using IndexedHybridUrlCodingStrategy for the page in question, and simply trying parameters "0" and "infoMessage" gives this exception:

WicketMessage: Not all parameters were encoded. Make sure all parameter names are integers in consecutive order starting with zero. Current parameter names are: [0, infoMessage]

If I change "infoMessage" parameter name into "1", it works, but yields an ugly URL (in this case something like /account/42/Tosite%20108207%20tallennettiin.5) which is not what I want.

---

Now, the obvious answer perhaps is that infoMessage shouldn't be in PageParameters. But thing is, I tried adding it as normal constructor parameter instead, like so:

public AccountPage(PageParameters parameters, String infoMessage) {
    // ...
}

But this approach fails in one important use case. After deleting a persistent "Record" object related to the Account, the following does not load the AccountPage properly (the deleted record is still visible). This code is executed in onClick() of an AjaxFallbackLink.

setResponsePage(new AccountPage(AccountPage.pageParameters(account), message));

On the other hand, my original approach...

setResponsePage(AccountPage.class, AccountPage.pageParameters(account));

... works fine, as it somehow loads the AccountPage "more thoroughly", but, again, I don't know how to pass the infoMessage parameter cleanly.

(AccountPage.pageParameters() above is a simple static utility for creating appropriate PageParameters with "0" = account id. The AccountPage constructor always loads the account from persistence using the ID.)

Any ideas? Perhaps using AjaxFallbackLink partially causes the problem?

Using Wicket 1.4.

回答1:

From what I see in your question, you try to render both a bookmarkable page and show a feedback message to the user (most probably in a FeedbackPanel), but you don't want that message to be part of the URL.

What you want to do is tell the Session that you have an informational message, and let the feedback panel handle the message.

@Override void onSubmit() {
    ... save object ...
    getSession().info("Object ... has been saved");
    setResponsePage(ObjectPage.class, new PageParameters("id="+object.getId()));
}

In this case you tell Wicket to temporarily store a message in the session, until it gets rendered by a feedback panel. This idiom is also known as "flash messages".

You can't use both PageParameters and another parameter as constructor arguments, because Wicket can't create your page instance with such a constructor when the page is requested. Wicket only knows how to instantiate pages with default constructors or pages with a PageParameters parameter.

来源：https://stackoverflow.com/questions/10189570/passing-info-message-to-a-wicket-page-while-using-pageparameters