Posted by bryantlikes on Dec 22, 2008 in
C#,
Dotnet |
View Original Article qingquan126778 asked the question in the Silverlight forums about how to switch between pages in Silverlight if the pages are in different xap files. First I pointed to Jesse Liberty’s post on multi-page applications (qinqquan wanted different xap files, not just pages) and then Mike Snow’s post on swapping between xap files using the ASP.NET server control (qingquan wanted client side only).
So since neither one was quite right, I coded up an example of my own that is based off Mike’s example but uses client side scripting instead of server side. Basically you grab a reference to the Silverlight plugin control via the onLoad event and then just set the Source property to the new xap.
function App2()
{
slCtl.Source = "ClientBin/SilverlightApplication2.xap";
}
Download Source Here
BTW – Did you vote on my 10k Content Entry yet? :)
Tags: Silverlight, WPF/E
Posted by bryantlikes on Dec 22, 2008 in
C#,
Dotnet |
View Original Article So my entry in the Mix 10K challenge is up in the gallery. It was a fun little project to create and I went well over 10k many times during the project and then had to whittle it back down each time. It is a feed reader that allows you to subscribe to feeds and it stores your subscriptions in Isolated Storage. I thought it was somewhat original, but then I watched this video on the contest and Adam even mentions an RSS reader, so I guess it was little obvious. :)
If you’re looking to enter the contest a few good posts on the subject are Adam’s post and Bill Reiss’ post.
Anyhow, check out my feed reader and be sure to vote!
Tags: Silverlight, WPF/E
Posted by bryantlikes on Dec 15, 2008 in
C#,
Dotnet |
View Original Article I’ve seen this question a number of times in the Silverlight Forums, so instead of just answering it one more time I decided to answer it here so I can refer back to this. The question generally looks like this:
I have create a dependency property and the setter isn’t getting called during data binding. My dependency property is declared as follows:
public class MyClass : Control
{
public int MyProperty
{
get { return (int)GetValue(MyPropertyProperty); }
set
{
SetValue(MyPropertyProperty, value);
// some custom code here
}
}
// Using a DependencyProperty as the backing store for MyProperty. This enables animation, styling, binding, etc...
public static readonly DependencyProperty MyPropertyProperty =
DependencyProperty.Register("MyProperty", typeof(int), typeof(MyClass), new PropertyMetadata(0));
}
The reason why the setter isn’t called here (at least the way I understand this), is that when data binding sets this value it isn’t calling the public property. Instead it is using the SetValue on the dependency object instead. So the custom code is never called. What you need to do is add a PropertyChangedCallback to the DependencyProperty registration as follows:
public int MyProperty
{
get { return (int)GetValue(MyPropertyProperty); }
set
{
SetValue(MyPropertyProperty, value);
}
}
// Using a DependencyProperty as the backing store for MyProperty. This enables animation, styling, binding, etc...
public static readonly DependencyProperty MyPropertyProperty =
DependencyProperty.Register("MyProperty", typeof(int), typeof(MyClass), new PropertyMetadata(0, MyPropertyChanged));
private static void MyPropertyChanged(DependencyObject o, DependencyPropertyChangedEventArgs e)
{
((MyClass)o).OnMyPropertyChanged((int)e.NewValue);
}
private void OnMyPropertyChanged(int newValue)
{
// custom code goes here instead
}
Now whenever the property changes the OnMyPropertyChanged method will get called. Notice that this is where you put your custom code to handle the property changing. This code will get called when the public property setter is called or when the property is changed using the SetValue method.
More information on Dependency Properties can be found here.
Tags: Silverlight, WPF/E
Posted by mehfuzh on Dec 7, 2008 in
ASP.Net,
C#,
Dotnet,
General |
View Original Article There could be plenty of reason that you might need to do a cross domain web request in your application. One could be let's say you want to divert the resource pressure from your server to some third party content provider like Amazon S3. In my last post I have mentioned a bit about uploading content using WSE to S3 server. I also mentioned about the simple library located at www.codeplex.com/threesharp that does not necessarily require you to work in full trust mode. This is also true if you have a personalized startpage where you want your wideget developers to restrict to partiuclar URLs.
Now, before starting it is worth mentioning that in medium trust mode any cross domain request is disabled by default. In other words, you can do calls only for your local endpoints.
How to get around this ?
When you install .net framework under %installed dir%\framework\version\config you will find a web_(high or medium or low)trust.config file that defines some policy about how your application will behave in a particular security level specified.
Now, to customize the default medium trust settings best is to copy it to your application directory so that you can tweaks thing only for your application and don't end up making it unstable in global scope. To show it as an example I have created a sample project that tries to do a web request, gets the data out and finally stuffs it to the response stream. To simulate, first let's put the following line in web.config which is pretty general for those of you works with it daily to strictly support medium trust in your app.
<trust level="Medium" /> // this is only for simulating in localhost
Next is to define your security level and config that will look for policies
<securityPolicy>
<trustLevel name="Medium" policyFile="web_mediumtrust.config"/>
</securityPolicy>
The above line will come into action only when medium trust is enabled. But here to note that if you dont have control over your hosting provider or your hosting has a <location allowOverride="false"> node in the root config then this approach won't work. Either you have to tell your hosting provider to add the requested URL for you or if you are doing things with your own hosting then you have to do it by yourself :-).
If you generally try to do a web request without any predefined policy defined in medium trust then you might see the following error
Request for the permission of type 'System.Net.WebPermission, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.
To overcome, once you have medium trust config in place you need to override the connectAccess property of WebPermission class. To do so , let's say I want to grant request for search.live.com and its descendant URLs, so the changes that I need to make looks something like the pasted.
<IPermission class="WebPermission" version="1">
<ConnectAccess>
<URI uri="http://www\.live\.com/.*"/>
</ConnectAccess>
</IPermission>
The default URL for requests in medium trust config is set to $OriginHost$ which says, "Can't let you do request to domains other than your own :-)" . The URL property takes regular expression and I can grant as many as URLs I want just by adding a new URL element and associating it with proper endpoint that my API or application might call. You can download the sample here and hope that helps a bit.
Update : As most of the shared hosting are with <location allowOverride="false"> the approach is useful only if you are a system administrator or want to have full control over your site by restricting your widget developers to a limited URLs
Enjoy !!!
Tags: Server, System Administration
