I really need some help with this as I have been trying to fix this for months and I can't figure it out.
I run an online chess site written in Silverlight 3.0
The architecture is Silverlight Client connecting to a WCF service that reads and writes data to a SQL Server database. It is hosted on Godaddy,
Once every so often I get the following error:
Could not load file or assembly ‘System.Web.Silverlight’ or one of its dependencies.
The system cannot find the path specified.
If I leave it alone it will fix itself after a few hours, however usually I just make a new publish of my application and it goes away. Also all the pages in the solution get this message not just the Silverlight application. So I have an aspx page with top ranks that does not use Silverlight but is in the same solution it also gets the same error. Its almost like the whole site dies.
This does not seem like a huge issue but it makes going on vacation hard since my site can go down at any time I am away. Also this seems to happen the most when I am sleeping so I often don't get to fixing it until I have already lost hours of potential logins.
This sounds like a ASP.NET problem. I suspect you are using ASP.NET with the Silverlight 2.0 ASP.NET server control. Ditch it and code the Object tag yourself, that way you no longer need that special assembly in your web site.
I received an answer on the Silverlight.net forums, it is a cobination of two items:
Like Anthony Suggested use an Object Tag to embed your Silverlight control.
Remove all refferences of System.Web.Silverlight from all your projects and never use it again.
Related
Recently I developed an application using a Pivot control as a "menu" and other pages with XNA content (2D and 3D).
Now, I discovered that my application won't be certified cause Im using System.XNA.Framework.Game and System.XNA.Framework.Graphics in my app.
This is really upsetting me at the moment, cause it's throwing away hours of work...
I never published something on the marketplace, so I'm asking if it's possible, anyway, to publish an application of this kind or at least, publish it as Beta Testing without "Certification" as they say on few pages..
Any clue?
Composite Silverlight+XNA applications are different from full-featured Silverlight applications invoking XNA assemblies. The restriction is still there - you must not have calls to Microsoft.Xna.Framework.Game or Microsoft.Xna.Framework.Graphics.
Mind you, some XNA elements are still allowed, such as Microsoft.Xna.Framework.Audio, that gives you access to the Microphone class, or Microsoft.Xna.Framework, that lets you access the FrameworkDispatcher.
I am planning to make a web application, using silverlight for frontend. requirement is: this frontend will be just an empty shell, and it must be language independent. it will get everything it needs to display and use from server, therefore making it language independent.
i tried to find tutorials, but there is nothing.
as far as i understand, silverlight uses xaml for all its data, so just generating it with whatever language i want shouldn't be a problem. but i don't have any silverlight experience or knowledge, so i'm not sure what is the best way to do this. for example, i don't know how will new content be generated, and what kind of structure silverlight requires.
can anyone give me some starting points?
Your requirements are rather demanding. If i can summarise:
silverlight will be the front end (or container)
you don't know what it will be showing
the content may be dynamically generated
everything, including the visual content, will be retrieved from the server
If i have misunderstood then by all means correct me or adjust your question.
Those requirements are not trivial, especially when you have no prior experience in Silverlight. Fetching data from the server is a normal behaviour in Silverlight, but fetching any generated UI content will be a slow and inefficient use of the technology platform. Silverlight is delivered via the browser, and runs on the client. If you are going to have generated UI, then you may want to consider using straight HTML instead (you can generate the contents using ASP.Net or a scripting language such as PHP). Alternatively, you can generate your required UI views from within the Silverlight app itself by either swapping in and out the appropriate pre-built piece of UI (or controls), programmatically adding new controls into the visual tree, or by loading XAML using the XamlReader class.
This answer may or may not help you much, but like i said before - put some more specific details into your question and you will get more specific answers (either add comments under your question, or post a new more specific question if you cannot edit your current one).
Edit: i have just come across this blog article from Jeff Prosise explaining the use of the INavigationContentLoader interface in Silverlight 4 to dynamically load pages from either remotely or locally. It is a detailed write-up, with a lot of code samples, it may be of use to you.
I would suggest you start at http://Silverlight.net
The "Learn" section has lots of videos that can get you started. http://www.silverlight.net/learn/
I want to develop a web Application to manage school administration. But I am not clear, which technology should I use to create Rich Internet Application. At present, develeopment company is going with ASP.net tools and say this is a web app.
However, there is page refresh on every click. Which I don't like. Please suggest, where to proceed.
Regards
Piyush
In a plain ol ASP.NET application, the screen refresh can be eliminated by using update panels in webforms, or by using more of the AJAX capabilities of the MVC Framework. (Wikiplex on Codeplex has a crazy simple example of this that I love in their example application).
Between Silverlight and Flash, however, Silverlight is designed to be a Web Application, or (at times) a desktop application in a Browser, while Flash is more of a multimedia framework.
Since it is school administration, which doesn't require random people to have Silverlight installed, Silverlight and JS/AJAX are both good options. Both are built into the ASP.NET set of libraries, and have good support in Visual Studio. Flash is a bit of an outsider in this regard.
So to sum up:
In general JavaScript/AJAX > Silverlight but either would be great.
If you are totally against any screen refresh, I'd lean more towards Silverlight.
If the developers are very familiar with Flash and communicating with the server with Flash, then I'd say it is also an option, but with no knowledge on all three and I'd not pick Flash first.
It's a little late for a response to the initiator. But I didn't agree with some of the answers I read here, and since google is popping this up in the search returns I felt compelled to align my answer on this board.
First off, a lot of developers create applications in ASP.NET and AJAX because they are comfortable with it not because the technology is better. For years, what it took one person to develop in the Adobe Flex framework, took many developers to create in AJAX. There is no more AJAX versus Flex, there's just Flex. Who wants to write a hundred lines of code in AJAX to do the same thing it takes 1 line of code in Flex. That's why the cost with an AJAX deployment was always more expensive.
On ASP.NET, you're right. Who wants to see the page refresh every time you perform an action? Not to mention, no browser follows the HTML implementations exactly, so how .NET app looks in 1 browser would look different in another browser, in addition to differences witnessed with the various browser versions.
Most ASP.NET, heck even Coldfusion Applications are clunky in HTML. So with that in mind all of my gui development is done in Adobe Flex. When a flash file is created, it compatible with 99% of the browsers (safari on mobile devices excluded), and all of the Operating Systems are supported. I'll tell you what, you can get silverlight to work in linux but have fun while it loads 50MB of MS software on your Linux OS. Not to mention Flash has a 99% market penetration. So it's already preloaded on machines and browsers.
Plus flash supports most picture formats and SVG natively. Did you know Silverlight became notorious because they don't support even a GIF/BMP formats? Forget SVG if you're using Silverlight because it doesn't support it. What's SVG? Look it up! It's only the most useful way to create any image you want right in a flex app. For instance maps are useful in SVG. AND its just a small file. Not a horrendous large file.
Language, Flex is just easier to program in and there's a lot of support for it. Think I'm kidding, try for yourself. You can download a Free version of flex for 30 days. Forgive my ignorance but I don't even know where to begin on loading Silverlight. I've got visual studio and all that but I gave up after trying. But that was 1 year after it's release so it may have changed.
And frankly, if you or a developer can't afford flex, DON'T BUY IT. Instead, download eclipse, which is free forever. Adobe Flex is only a special iteration customized by Adobe anyway. So you probably won't get charting and some other components in eclipse, but most of the GUI components are built right into Eclipse.
Programming ASP.NET is just old hat. It's clunky, difficult to work with and it's possible to corrupt the files. It's not possible at all to corrupt your project files in Flex/Eclipse because they are just TEXT files. How cool is that?
Don't get me wrong, I program in ASP.NET too. But I like it for Application server processes; you know like the middleman between database and client. SQL server feeds ASP, and ASP feeds my Flex GUI using SOAP. Big plus is even though I hate Visual studio crystal reports, it's still way better than nothing. Believe me you want to have some reporting possibilities like CF Report Builder or crystal reports. Some people just like a nicely formatted PDF and that's all there is to it.
I've released hundreds of applications using various technologies. Right now this is my favorite. But frankly, a good GUI can be done anywhere if you are a 'kung fu' master. I'm saying that although it's easier out of the gates to program in Flex compared to .NET/Silverlight, someone with some mad .NET skills can put a Flex app to shame. But as it stands right now, there is no argument that Flex is the stronger candidate with the most market penetration, flexibility, and ease of use.
Good luck all...
ASP.NET does provide some special sauce for AJAX, so it's entirely possible to eliminate the page load without leaving ASP.NET. If you leave ASP.NET, the options are endless: Java, Silverlight, JQuery, Flash, etc. ad infinitum.
Silverlight and Flash are great for richer user interfaces, however I dont think they should be used for the "whole" interface or application. Its best to narrow down these parts and decide how rich these need to be, then evaluate which technology to use. If you just want to prevent full round trips to the server on a page, AJAX is a good option. I would also recommend Silverlight over Flex, since you probably/already have the tools.
I am working on my first DotNetNuke website and there is a requirement for all the custom module functionality I am developing to be available with JavaScript disabled.
However, when I create a module that contains a simple submit button, i.e.<input type="submit" />, DotNetNuke displays a critical error with JavaScript turned off but works as expected with JavaScript turned on.
When I attach to the running process using Visual Studio, the unhandled exception is thrown from admin/Skins/Nav.ascx.vb line 177. The inner exception message is "Invalid JSON primitive: ."
My research online only managed to turn up this forum post (Postbacks are not working when Javascript is disabled in the browser) that appears to be the same problem as mine, but no solution is provided.
Can anyone shed any light on this issue? Is it viable to be attempting to write non-JavaScript functionality in this version of DotNetNuke?
Update: it turns out that another website designed recently with Dot Net Nuke by the company I am working for is having the same problem with non-javascript postbacks when using DNN version 5.1.4 but it does not have the problem (i.e. it can postback without javascript) in DNN version 5.0.1.
So perhaps a hard dependency on javascript has been introduced at some point after version 5.0.1. We are investigating this possibility further and I will keep this question updated as we go. Obviously I still welcome anyone's input on the subject.
Update: i've started a thread on the Dot Net Nuke forums to see if I can get any help there. If any solutions come up I'll post them here. Trying to find official DNN stance on support for javascript disabled functionality
One of the developers in the office found a workaround to get postbacks working with javascript disabled. Unfortunately since he does not have a Stack Overflow account, I will try to translate his solution as best I can for those who are interested. Bottom line is postbacks with Javascript disabled is possible once you make a few changes to the Dot Net Nuke environment.
Step 1 - Change the menu module. In our case we used the Telerik RadMenu.
<dnn:NAV runat="server" id="dnnNAV" ProviderName="DNNMenuNavigationProvider" IndicateChildren="false" ControlOrientation="Horizontal" CSSControl="mainMenu" />
becomes
<dnn:RADMENU runat="server" id="dnnRADMENU" MaxLevel="2" EnablePageIcons="False" PagesToExclude="" ShowPath="True" />
Step 2 - Remove the actions and visibility modules.
<dnn:ACTIONS runat="server" id="dnnACTIONS" ProviderName="DNNMenuNavigationProvider" ExpandDepth="1" PopulateNodesFromClient="True" />
<dnn:VISIBILITY runat="server" id="dnnVISIBILITY" minicon="images/DNN-minus.gif" maxicon="images/DNN-plus.gif" />
Step 3 - Download the DNN source and make two changes in the LibraryUI\Utilities\ClientAPI.vb file.
Line 155:
DotNetNuke.UI.Utilities.ClientAPI.RegisterClientReference(objButton.Page, DotNetNuke.UI.Utilities.ClientAPI.ClientNamespaceReferences.dnn_dom)
becomes
If Not objButton.Page.IsPostBack Then
DotNetNuke.UI.Utilities.ClientAPI.RegisterClientReference(objButton.Page, DotNetNuke.UI.Utilities.ClientAPI.ClientNamespaceReferences.dnn_dom)
End If
Line 355:
ClientAPI.GetCallbackEventReference(objPage, "", "", "", "")
becomes
If Not objPage.IsPostBack Then
ClientAPI.GetCallbackEventReference(objPage, "", "", "", "")
End If
Step 4 - compile the Dot Net Nuke library.
Note: Also make sure you are not logged in as an admin or host, as the admin/host panel at the top of the page will also break if you attempt to postback with javascript disabled.
Hope this helps someone else. If you feel like I'm missing some important details, let me know and I'll try and fill in what's needed.
DotNetNuke relies heavily on JavaScript and I doubt there is a real easy way around it - at least considering you need to support all functionality. Perhaps you can clarify that?
The the bottom line here is that you're going to need to modify DotNetNuke to meet your needs. It certainly isn't impossible to get it working, but I would venture a guess that it just plain isn't worth it for most people.
If, as you said, you need to retain ALL functionality without using JavaScript, you're going to have a pretty substantial amount of work to do.
I'd suggest, to get started, you download the source package, set up a development environment on your local machine, turn off JavaScript in your browser and start taking notes. This will help to determine the level of effort involved.
I'm guessing you won't get a lot of responses out of this one (as the poster in the forum thread you linked to didn't) as very few people have sat down in front of DotNetNuke with this as a requirement.
Also, keep in mind that any time you're making substantial changes to the DotNetNuke framework, you're interfering with your ability to easily perform upgrades in the future. Just another thing to think about.
I believe that I've seen the leadership in DNN say that they've taken a hard dependency on JavaScript, and have no intention at this time of considering a non-JavaScript compatible scenario.
That being said, being able to do a simple postback shouldn't be too difficult to support. I would look around in the Client API area for the error that you're describing. A lot of the Client API code is in the DotNetNuke.WebUtility assembly, which is a separate download from CodePlex to get the source.
First I'd like to make it clear, I'm not looking for a "my tech is better than yours" type of post; this is a real case scenario and I have been faced with this decision. With this in mind, let me explain:
We have a WinForms application. It started in the early .NET 1.0 but the first shipping version was using .NET 1.1. There are layers (like BusinessLayer.dll, Datalayer.dll, Framework.DLL, etc.) but at some point during the "long" development cycle of this application, the "presentation" layer (Win Forms) got infected with some code, thus the "separation between the code and the presentation with code behind" is some sort of myth.
Bad practices or whatever, the truth is that the application is there and it works.
Years passed and we had .NET 2.0, we slowly migrated and it mostly worked, had to change a few calls here and there. Last version did the same thing, but for .NET 3.5sp1. We needed some sort of Webservices thing, and decided to use WCF instead. It works fine.
But despite all these .NET upgrades, most of the application's codebase is still the same old rock and roll from 5 years ago. We use Gentle.NET (old and unmaintained now) for our dataobjects (it was a blessing 5 years ago!).
Our presentation layer, the winforms, are "nice looking" since we employ 90% of completely gdi+ custom controls. (whenever possible without having to hack the WinAPi). The application is touch based (i.e.: it makes use of the Ink but it doesn't rely on that), but the buttons, labels, etc, everything is "designed" to be used with a tactile device. (TabletPC or Touchscreen). Of course some users use keyboard/mouse.
With all that in mind, and with all this web2.0 and Internet fuzz (plus Jeff's posts ;) ), we are considering the possibility of rewriting the application but using a web technology.
The idea is obviously bringing more availability for our customers (they can use the system whenever/wherever they want), and less maintenance (we can upgrade and it is an instant upgrade for 'em all), etc. You know, the usual Internet vs WinApp thingy.
The problem is that given that this is the healthcare industry, not all of our customers might be willing to "move" their databases to our server/s, which is acceptable, and would force us to install a webserver/database server in their own servers so they have their own copy. Not a big problem (except we would have to update those manually but that's not an issue, given that we've been updating win32 apps for 5 years now!).
Now, back to the main "question".
The team has little Asp.NET experience, we did program a lot in ASP 2.0 (in 1999/2000) but that was a spaghetti of HTML+VBScript+CSS, so I don't think it counts. After all that experience (the Internet bubble!) we went back to VB6 then C#.NET 1x and you know the rest of the story. We're a small team of C# developers for WinForms. We've acquired some Linq To SQL Experience in our last .NET 3.5 ride, and we liked it. We felt it very natural and very "if we would have had this five years ago…" like.
Given all this, rewriting the application is not a "simple task" (not even if we wanted to do it in the already known C#.NET), it would take time and planning, but we could correct dozens of mistakes and with 5 years of experience working with the application, we now can say that we have a better idea of how the customers would like to use the software and what limitations we created (by ourselves) when we designed the current app.
All that "knowledge" of the application and the way the business works, could be applied to produce a much better application in terms of design and code and usability. Remember in .NET 1.1 we didn't even have generics! ;) (you'll see lots of ArrayList's hanging around here).
As an additional note, we use Crystal Reports (and, as usual, we hate it). We don't think the ink control is a "must" either. The HTML/CSS could be shaped to look the way we want it, although we're aware that HTML is not WinForms (and hence some things cannot be reproduced).
Do you think that planning this in MVC (or WebForms) would be too crazy?
I like the MVC (ruby on rails like) idea (I've never programmed in ruby beyond the basics of the book), so no one in our team is an expert, but we can always learn and read. It mustn't be "rocket science", must it?
I know that this whole question might be a little bit subjective, but would you replace an aging Winforms application with a new ASP/MVC/XXX web application? Do you have experience or have tried (and had success or failed) ?
Any insight in helping use better decide what to do will be appreciated.
Thanks in advance!
UPDATE: Thanks to all who responded, we'll evaluate whether this is a good move or not, it sure is a hell of work, but I am afraid the the desktop app is getting older (using old net 1.1 hacks) and tho it has been more or less working without problems in Vista and W7, I'm afraid a future update may break it.
Also, lots of "more or less core" parts of the application are exposing some badly designed ideas and we had to hack here and there to accomplish certain tasks. Part inexperience, part lack of 100% knowledge of how the business worked (and Customers not sure what they wanted).
A new application (in any form) would allow us to create a better foundation while retaining all the user knowledge.
But, it's a L O T of work :) So we'll consider all these options here.
As some of you have mentioned, maybe a thinner client and some (ab)use of WCF here and there might be more appropriate.
Once again, thanks to all!
It would be best to ditch all your efforts of reusing the desktop application code when you recreate the web app. Following are the reasons:
Web apps especially asp.net use a different model. For starters note http is stateless. Each time the browser talks to server you have to explicitly send the current content of all the controls on the current page. You would not have used such a model in your Windows application.
To decrease load on the network you want to optimize the size of viewstate and how frequent you make http requests. Again your existing window app does not have any such provisions.
Updating view. You might have different event handlers, threads and what not in your windows application to update the GUI in different scenarios. All of that will need to be replaced. Javascript is a totally different animal.
Security. When using a browser your access to the local disk is highly limited whereas you will take the same for granted in windows application. If there is any code in the windows app that requires local resources, then that is going to be a trouble spot for you.
I would recommend the following:
Verify if your current application has any local disk access requirements (e.g. read/write to local file etc).
As you write the different http modules or handlers, you can try leveraging some of the backend/ business logic part of the existing windows application.
Give some thought to what part of your application can become a web service.
It sounds like the application needs a lot of refactoring to clean it up. If you want to move to a web model, and have maximum reuse you will really need to do that. Before you move to a web model I think you need to understand if it will be possible to replicate your user interface in that model. Is it your unique selling point from a customer perspective? You want decisions like this to be user driven rather than purely technical decisions.
It sounds like your application is the perfect candidate for a thick client application, rather than the lowest common denominator web model.
Some things to consider:
How will the web interface impact the Tablet interaction?
What new customers will having a web version bring you?
Will existing customers abandon your product?
Do you have access to consultants or outside resource with the right skills to mentor you in web technology? If you don't you can rely on StackOverflow or other web resources to help. You need some good mentoring and guidance on the ground with you.
What happens if you start this effort and it takes much longer than you expect? You know the app but don't sound like you know the web. Past experience shows that massive rewrites like this can end in disaster (it never sounds so difficult at the start)
Can you possibly write new features in a web-based version?
Could you move to ClickOnce deployment to make the application easier to deploy to customers. One of the benefits of the web is easier (zero) deployment. Can you get closer to that?
Would it be easier to migrate to WPF and create a browser application with that?
Silverlight or Flex might be better options for creating a rich experience, and may be more approachable for WinForms developers. Is this a possibility?
It seems like your app. is one of those that works best as a desktop app. Though you want your users to be able to access your app. using a browser.
I would suggest refactoring as much as possible so that the GUI gets cleaner and don't have "code".
When you've done this, start developing a asp.net mvc app but keep your desktop app. You should be able to use all layers except the UI layer, making it easier/faster/... Now that mvc exists, I'd say webforms is more about letting non-web devs do web. But you know web, sort of, and you want control so mvc is the way to go.