Jonas Stawski

JavaScript not working within UpdatePanel

Jonas Stawski — Mon, 02 Nov 2009 14:03:00 GMT

The other day I was having a problem with JavaScript functions not being found. The simplified setup was similar to this:

- UpdatePanel
   - UserControl (Visible = true)
   - UserControl (Visible = false)
      - Embedded JavaScript and Controls

There was some controls on the page that triggered an asynchronous postback which changed the visibility of the UserControls and when the Embedded JavaScript was called I was getting JS errors. Here’s the question I asked on the forums: http://forums.asp.net/t/1484503.aspx.

According to InfinitiesLoop:

The over simplified way of explaining how UpdatePanel does its work on the client is through the innerHTML DOM property. When a delta is retrieved from the server, it finds itself in the existing DOM, disposes of the contents, and then assigns the new content via innerHTML. Thanks to a basically consistent behavior across the major browsers, the new content appears just as if it were there to begin with.

But inline script doesn't work this way. Setting the innerHTML of a DOM element to HTML which contains a script block does not cause that script to execute. The only way to execute arbitrary script dynamically is to eval() it directly, or dynamically create a script element with document.createElement("script") and inject it into the DOM.

So to solve my problem I dynamically created the embedded JS through the use of the ScriptManager on the Page Load:

        1: ScriptManager.RegisterClientScriptBlock(this, this.GetType(), "SomeUniqueID", "function HelloWorld() { alert('Hello World'); }", true);

Happy Programming!

2009 Buenos Aires CodeCamp – Presentations Available

Jonas Stawski — Wed, 07 Oct 2009 18:49:11 GMT

Presentations from the 2009 Buenos Aires CodeCampare now available through the official Argentina TechNet and MSDN Facebook Page. You can find the content under the “Contenidos Tecnicos”: http://www.facebook.com/ComunidadesMicrosoft?v=app_7146470109&ref=nf

Happy Programming!

Se viene el Buenos Aires Code Camp 2009

Jonas Stawski — Fri, 11 Sep 2009 16:01:21 GMT

Este año va a ser aun mas grande que el año pasado. Tenemos 12 charlas en paralelo en 4 horarios diferentes. Más de 50 oradores del todo el país compuesto por MVPs, MSPs, empleados de Microsoft, profesionales y estudiantes. Algunos de los temas son Windows y SQL Admin, ASP.NET, .NET 4.0, WPF, Silverlight, XNA, y mucho mas.

El evento es el Sábado, 26 de Septiembre a de 10:00 a 19:00 en la Universidad de Palermo.

Te lo vas a perder? http://www.codecamp.com.ar/home.aspx

Sample Code for Getting the User Location based on the IP Address

Jonas Stawski — Thu, 03 Sep 2009 18:01:36 GMT

Yesterday I introduced a free service to get the location of the IP Address. If you haven’t read it, go on read that first (it’s very short, I promise). So here I am today, showing you my small .NET API to abstract the XML returned by the service.

First we need an object to hold the data. I called it UserLocation.

        1: public class UserLocation

       2: {

       3:     public string City { get; set; }

       4:     public string Country { get; set; }

       5:     public string CountryAbbrev { get; set; }

       6:     public double Latitude { get; set; }

       7:     public double Longitude { get; set; }

       8: }

Then I created a helper class to retrieve the info. I called it GeoLocation:

       1: public class GeoLocation

       2: {

       3:     //you might want to retrieve this from a config file

       4:     private static string ServiceAddress = "http://api.hostip.info/?ip={0}";

       5:     public static UserLocation Locate(string ipAddress)

       6:     {

       7:         string url = String.Format(ServiceAddress, ipAddress);

       8:         //Get the XML from the request

       9:         XmlDocument xml = GetXml(url);

        //Parse the XML into a UserLocation

        return ParseUserLocation(xml);

    }

  

    private static XmlDocument GetXml(string url)

    {

        HttpWebRequest myReq = (HttpWebRequest)WebRequest.Create(url);

        myReq.Method = "GET";

        HttpWebResponse myResp = null;

        XmlDocument xml = null;

        try

        {

            myResp = (HttpWebResponse)myReq.GetResponse();

            if (myResp != null && myResp.StatusCode == HttpStatusCode.OK)

            {

                Stream dataStream = myResp.GetResponseStream();

                StreamReader reader = new StreamReader(dataStream);

                xml = new XmlDocument();

                xml.LoadXml(reader.ReadToEnd());

  

                reader.Close();

                dataStream.Close();

                myResp.Close();

            }

        }

        catch

        {

            xml = null;

        }

  

        return xml;

    }

  

    private static UserLocation ParseUserLocation(XmlDocument xml)

    {

        UserLocation location = null;

        if (xml != null)

        {

            try

            {

                XmlNamespaceManager nsMgr = new XmlNamespaceManager(xml.NameTable);

                nsMgr.AddNamespace("gml", "http://www.opengis.net/gml");

                

                XmlNode node = xml.SelectSingleNode("/HostipLookupResultSet/gml:featureMember/Hostip", nsMgr);

                if (node != null)

                {

                    location = new UserLocation();

                    XmlNode childNode = node.SelectSingleNode("gml:name", nsMgr);

                    if (childNode != null)

                        location.City = childNode.InnerText;

  

                    childNode = node.SelectSingleNode("countryName", nsMgr);

                    if (childNode != null)

                        location.Country = childNode.InnerText;

  

                    childNode = node.SelectSingleNode("countryAbbrev", nsMgr);

                    if (childNode != null)

                        location.CountryAbbrev = childNode.InnerText;

  

                    childNode = node.SelectSingleNode("ipLocation/gml:pointProperty/gml:Point/gml:coordinates", nsMgr);

                    if (childNode != null)

                    {

                        string[] coord = childNode.InnerText.Split(',');

                        if (coord.Length == 2)

                        {

                            double tmp = 0.0;

                            double.TryParse(coord[0], out tmp);

                            location.Longitude = tmp;

                            double.TryParse(coord[1], out tmp);

                            location.Latitude = tmp;

                        }

                    }

  

                    //make it null because it couldn't find it

                    if (location.CountryAbbrev == "XX")

                        location = null;

                }

            }

            catch

            {

                location = null;

            }

        }

        return location;

    }

}

As you can see. First we use the request API from .NET to make a request to the service and parse the request into an XML. Then we use the XML to parse it into our UserLocation object which will then be used by our web application. This is not a critical part of my application, so I decided that for any problem that I might encounter I will return null. In the web app I will only use the information if it’s not null.

       1: UserLocation location = GeoLocation.Locate(Request.UserHostAddress);

       2: if (location != null)

       3: {

       4:     //TODO: Do something with it

       5:     //location.City

       6:     //location.Country 

       7:     //location.CountryAbbrev 

       8:     //location.Latitude

       9:     //location.Longitude 

      10: }

The code above shows how to use the GeoLocation helper method from the web page or any other object.

Enjoy and Happy Programming!

Get Location of the IP Address

Jonas Stawski — Wed, 02 Sep 2009 19:00:48 GMT

I wanted to share with all of you a free service that provides you an approximation of your user’s IP Address. You can read about it here: http://www.hostip.info/use.html. If you are looking for a more sophisticated solution that is maintained more often than the free solution you can also use this service: http://www.maxmind.com

As of this writing you can get the response in 2 different forms: XML or plain text. I like the more structure formats so I will be using the XML option.

Stay tune… I will post a C# API for retrieving the information.

UPDATE: You can now see the code here.

Happy Programming!

Visual Studio 2010 Beta 1 Painfully Slow

Jonas Stawski — Thu, 23 Jul 2009 03:23:33 GMT

Remember that blog I wrote about installing VS 2010 in a Virtual Machine? Well, as I type this I’m doing a fresh install of VS 10 in my Windows 7 RC machine (not a VM). I just can’t take it anymore. Visual Studio 10 Beta 1 is painfully slow running on my Quad Core 8 GB Computer as a Virtual Machine. I even have the virtual hard drive file running on a second drive.

You know, when I read about people like Scott Hanselman and Joel Spolsky writing about how the speed of their hard drives (SSD) makes such a huge difference and how they can save 10 minutes a day I just don’t get it. But now that I’ve been on the other side of the spectrum I can see how having a slow machine can really negatively affect your performance.

I think my development speed has slowed down to half of my normal speed. Sometimes, while debugging, it is so slow that I just get up and scream. Hopefully I won’t see this problem running VS 10 in a physical machine (finger’s crossed).

Routing in ASP.NET 3.5 and 4.0

Jonas Stawski — Fri, 17 Jul 2009 23:52:38 GMT

Routing was born with the creation of the asp.net MVC Framework. During the beta testing of the MVC framework people started asking for this feature to be included in asp.net so it could be used with web forms as well. The asp.net team listened and included Routing with the release of .net 3.5 SP1. Thanks for the history, but what exactly is routing?

Routing enables you to use URLs that do not map to a physical location on the server. For example in a normal page request for the default.aspx resource there has to be a physical file default.aspx on the server. On the other hand with routing you can map different URLs to a single resource. For example a normal web app might use the file Product.aspx to display product information and use the querystring as an input parameter for the Product ID resulting of a URL similar to this: Products.aspx?productID=345. The same can be accomplished with Routing, but with the difference that the URLs can be more human readable and hence more related to an action. The above example can be implemented as something like /ShowProduct/345. Search engines are not very friendly to URLs with querystring parameters and utilizing the Routing methods allows you have a more Search Engine Optimized website.

There is already a similar mechanism that accomplishes the same and it is called URL Rewriting. With URL Rewriting the incoming requests is processed and changes the URL before sending it to the actual page. If tomorrow the “fake” URL is changed the web application needs to change all URLs that utilizes it. With asp.net Routing, the URL request is not changed and there is an API that creates your URLs for a specific route. If tomorrow you decide to change the URL of a route you simply change it in one place and all your references that uses the API to create the URL are changed by default.

In order to take advantage of asp.net Routing, you have to define each route and you do so in the application_start of the global.asax:

        1: void Application_Start(object sender, EventArgs e) 

       2: {

       3:     // Code that runs on application startup

       4:     //Add the routing information for when the user clicks on a category

       5:     System.Web.Routing.Route categoryRoute = new System.Web.Routing.Route("{CategoryName}/{CategoryID}", new System.Web.Routing.PageRouteHandler("~/category.aspx"));

       6:     categoryRoute.Constraints = new System.Web.Routing.RouteValueDictionary { { "CategoryID", @"\d{1,5}" } };

       7:  

       8:     System.Web.Routing.RouteTable.Routes.Add("CategoryRoute", categoryRoute);

       9:  

      10:     //Add the routing information for when the user clicks on a subcategory

      11:     System.Web.Routing.Route subCategoryRoute = new System.Web.Routing.Route("{CategoryName}/{SubCategoryName}/{CategoryID}/{SubCategoryID}", new System.Web.Routing.PageRouteHandler("~/subcategory.aspx"));

      12:     subCategoryRoute.Constraints = new System.Web.Routing.RouteValueDictionary { { "CategoryID", @"\d{1,5}" }, { "SubCategoryID", @"\d{1,5}" } };

      13:  

      14:     System.Web.Routing.RouteTable.Routes.Add("CategoryRoute", categoryRoute);

      15:  

      16: }

in the code above we are declaring 2 routes and what we are saying is that whenever there is a request in the form of [string]/[id] to route it to the category.aspx page and whenever there is a request in the form of [string]/[string]/[id]/[id] route it to the SubCategory.aspx page. What I like to point out here is that you can specify with placeholders what each location represents and if there are any constraints. For example the first string on the first route represents the CategoryName while the second one represents the CategoryID. On line 6 we can also see that CategoryID can only be a digit of 1 - 5 characters in length and we do so with regular expresions. So if the users is trying to tamper with the URL and enters a non digit string or a 6 digit number, asp.net will not find a matching Route and display a 404 (Page Not Found) error. If you ask me that is a beautiful thing and makes your job as a developer a heck lot easier. Now you know for sure that the category id will for certain be a number and not a string and hence you don’t have to worry about possible runtime conversion errors.

This is cool, but how do I create the URLs for my routes. You do so by using the Routing API:

       1: RouteTable.Routes.GetVirtualPath(null, new RouteValueDictionary { { "CategoryName", "Suitcases" }, { "CategoryID", 1 } }).VirtualPath;

in the sample code above we see that we are using the helper method GetVirtualPath of the Routes object. We pass in a RouteValueDictionary which is a dictionary containing the name and value of each parameter. So you can see that the CategoryName is Suitcases and it’s ID is 1. This would result in the URL: /Suitcases/1 and when browsing to this URL the category.aspx page will be called. If for whatever reason you decide to change the URL from /CategoryName/CategoryID to /Category/CategoryName/CategoryID, all you have to do is change the Route definition in the Global.asax and all references that use the API call to construct the URLs will be changed automatically.

To access the values of the routes you also use the Routing API like this:

       1: Page.RouteData.Values["Category"];

which returns an object.

I hope you see how important Routing can be to your web application and start using it on your current and future projects.

Happy Programming!

MVP For Third Year in a Row

Jonas Stawski — Tue, 07 Jul 2009 13:27:36 GMT

On July 1st I was given the news that I will be part of the elite group of the 2009 MVP (Microsoft Most Valuable Professional) program. The program consists of about 5000 people around the globe and is given to people who contribute to the Microsoft development and IT community for speaking at events, writing articles, blogging, and participating in forums. I was awarded the Visual C# MVP and you can see my profile here.

I would like to thank everyone who attends my sessions, read my blog, read my articles, and give me the opportunity to answer their questions online. I look forward for another great year…

Happy Programming!

Installing Visual Studio 2010 Beta on a Virtual Machine

Jonas Stawski — Sat, 13 Jun 2009 14:39:37 GMT

For the release of Visual Studio 2010 RC (Release Candidate), Microsoft provided us with a fully installed VPC (Virtual Machine) image. For some reason they did not do the same for the release of Beta 1. I guess they wanted people to go through the installation so they can receive feedback and bugs for it. Anyway, if you want to install VS 2010 Beta in a Virtual Machine, I recommend watching this Channel 9 Videoby Brian Keller on how to download and install all the requirements. Keep in mind that Brian also installs VS Team Foundation Server which is not needed if you only want to play with VS 2010. Therefore you can skip the steps to install SQL Server 2008 and VS TFS 2010.

Happy Installing!

SQL Server 2008 Spatial Data and Virtual Earth Files

Jonas Stawski — Thu, 14 May 2009 13:11:59 GMT

Thanks to everyone who showed up for the Miramar.NET user group at Devry University. You can now download the presentation and demos from here.

Happy Programming!