Mailing-List: contact tapestry-user-help@jakarta.apache.org; run by ezmlm
Precedence: bulk
Reply-To: "Tapestry users" <tapestry-user@jakarta.apache.org>
From: =?iso-8859-1?Q?Petter_M=E5hl=E9n?= <petter.mahlen@elevance.se>
To: "'Tapestry users'" <tapestry-user@jakarta.apache.org>
Subject: RE: Form rewinding and updating properties
Date: Tue, 23 Mar 2004 22:39:40 +0100
Message-ID: <000401c4111f$59173cd0$ce8f59d5@elevanceone>
MIME-Version: 1.0
Content-Type: text/plain;
	charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
In-Reply-To: <4060A444.5040900@u.arizona.edu>
Importance: Normal

The exception is because the 'course' property is null. If you need the =
page
to maintain the same value for 'course' when the form is rendered (shown
during the GET) and rewound (during the following POST), it needs to be
persistent. Otherwise, the value will be lost in between the two HTTP
requests. Most likely, setting it to persistent will solve your problem, =
but
it's a bit hard to be sure without more information.

/ Petter

> -----Original Message-----
> From: Robert Zeigler [mailto:rdzeigle@u.arizona.edu]=20
> Sent: den 23 mars 2004 21:56
> To: Tapestry users
> Subject: Form rewinding and updating properties
>=20
>=20
> Hi,
>=20
> I'm pretty new to tapestry and still trying to get the hang of the=20
> "tapestry way" of doing things.
> I've got a page that lists out student information (student's=20
> name, etc.=20
> as well as updatable information about the courses a student=20
> is enrolled in,
> section, status, etc.). I've got the page so that it loads correctly,=20
> finally, but if I try updating the information, I get an ognl=20
> exception:
>=20
> Unable to update expression 'course.currentSection' for=20
> org.eledge.sms.pages.ViewStudent$Enhance_307@169c9a2[ViewStude
> nt] to null.
> binding: 	ExpressionBinding[ViewStudent course.currentSection]
> location: 	context:/WEB-INF/ViewStudent.page, line 56, column 67
> =20
>=20
>=20
> ognl.OgnlException
> target is null for setProperty(null, "currentSection", null).
>=20
> Essentially, what happens is that the  page is passed an array of=20
> student objects, and the information obtained from there...
> each student object contains an array of course objects, and that's=20
> where the values are (supposed to be) coming from...
> like I said, things work when displaying the form. I'm still a little=20
> unclear on how the whole "rewind" process works, and I=20
> suspect that's where
> my problem is coming from...
> None of the page properties are (students, course, etc.) are=20
> persistent,=20
> and I'm wondering if that's the problem;
> however, i've also tried changing the top level students array, from=20
> which all of the other objects are obtained, to be persistent, and I=20
> still wind up with the
> same problem.  Any ideas/thoughts/help would be appreciated. Thanks!!
>=20
> Robert
>=20
> ---------------------------------------------------------------------
> To unsubscribe, e-mail: tapestry-user-unsubscribe@jakarta.apache.org
> For additional commands, e-mail: tapestry-user-help@jakarta.apache.org
>=20


---------------------------------------------------------------------
To unsubscribe, e-mail: tapestry-user-unsubscribe@jakarta.apache.org
For additional commands, e-mail: tapestry-user-help@jakarta.apache.org