CompletIT Community Server

Animating ListBox items - the VisualStateManager

idragoev — Fri, 13 Jun 2008 13:13:00 GMT

Check out my second article on ListBox items animations. Here you can see how to use VisualStateManager and also some problems I faced during the migration to Silverlight 2 beta 2

Enjoy!

Moving ViewState to the bottom of the page

nraychev — Mon, 02 Jun 2008 13:51:00 GMT

We noticed that the ViewState in silverlightshow.net was enormous so we decided to make some improvements. The first step was to move it to the bottom of the page just for the search engine optimization. I have met many articles in internet which describe how to do this. One of them which I have used is:

http://www.hanselman.com/blog/MovingViewStateToTheBottomOfThePage.aspx

I’ll describe the solution which worked for us:

I created a class named SLSPage which extends the System.Web.UI.Page class and made all ASP.NET pages inherit this class instead of the Page class. Here our class is:

using System.Text.RegularExpressions;
using System.IO;
using System.Web.UI;
using System;
using System.Configuration;

namespace SilverlightShow
{
    public class SLSPage : System.Web.UI.Page
    {
        #region Constants
        private static readonly Regex viewStateRegex = new Regex( @"<input\s+type=""hidden""\s+name=""__VIEWSTATE""\s+id=""__VIEWSTATE""\s+value=""[^""]+""\s*/>", RegexOptions.IgnoreCase | RegexOptions.Multiline | RegexOptions.Compiled );
        private static readonly Regex endFormRegex = new Regex( @"</form>", RegexOptions.IgnoreCase | RegexOptions.Multiline | RegexOptions.Compiled );
        #endregion

        #region Handlers
        protected override void Render( System.Web.UI.HtmlTextWriter writer )
        {
            string originalHtml = string.Empty;
            string newHtml = string.Empty;

            using ( StringWriter stringWriter = new StringWriter() )
            {
                using ( HtmlTextWriter htmlWriter = new HtmlTextWriter( stringWriter ) )
                {
                    base.Render( htmlWriter );
                    originalHtml = stringWriter.ToString();
                }
            }

bool success = false;

Match viewStateMatch = viewStateRegex.Match( originalHtml );

            if ( viewStateMatch.Success )
            {
                string viewStateString = viewStateMatch.Value;
                newHtml = originalHtml.Remove( viewStateMatch.Index, viewStateMatch.Length );

Match endFormMatch = endFormRegex.Match( newHtml, viewStateMatch.Index );

                if ( endFormMatch.Success )
                {
                    newHtml = newHtml.Insert( endFormMatch.Index, viewStateString );
                    success = true;
                }
            }

            if ( success )
            {
                writer.Write( newHtml );
            }
            else
            {
                writer.Write( originalHtml );
            }
        }
        #endregion
    }
}

We have two constant, precompiled Regex objects. The first matches the hidden field named __VIEWSTATE and the second – the closing tag of the form. Note that our solution will work only if we have only one form – the server form, but it is common scenario in ASP.NET.

#region Constants
private static readonly Regex viewStateRegex = new Regex( @"<input\s+type=""hidden""\s+name=""__VIEWSTATE""\s+id=""__VIEWSTATE""\s+value=""[^""]+""\s*/>", RegexOptions.IgnoreCase | RegexOptions.Multiline | RegexOptions.Compiled );
private static readonly Regex endFormRegex = new Regex( @"</form>", RegexOptions.IgnoreCase | RegexOptions.Multiline | RegexOptions.Compiled );
#endregion

Then I override the Render method where we have full control on the rendered html.

In this method I declare two string variables – one for the original rendered html and one for the html in which the ViewState will be at the bottom.

string originalHtml = string.Empty;
string newHtml = string.Empty;

I use the Render method of the Page class in order to render the html into a HtmlTextWriter , named htmlWriter, which wraps a StringWriter named stringWriter. Then I use the ToString method of the StringWriter in order to load the rendered html in the originalHtml variable.

using ( StringWriter stringWriter = new StringWriter() )
{
     using ( HtmlTextWriter htmlWriter = new HtmlTextWriter( stringWriter ) )
     {
           base.Render( htmlWriter );
           originalHtml = stringWriter.ToString();
     }
}

Then I declare a Boolean variable called success, which by default is false:

bool success = false;

This variable will be set to true only if all operations for moving the ViewState succeed. The following code moves the ViewState:

Match viewStateMatch = viewStateRegex.Match( originalHtml );
if ( viewStateMatch.Success )
{
string viewStateString = viewStateMatch.Value;
newHtml = originalHtml.Remove( viewStateMatch.Index, viewStateMatch.Length );

    Match endFormMatch = endFormRegex.Match( newHtml, viewStateMatch.Index );
    if ( endFormMatch.Success )
    {
         newHtml = newHtml.Insert( endFormMatch.Index, viewStateString );
         success = true;
    }
}

If the first match succeeds I remove the ViewState, save it in a temp variable named viewStateString, save the changed html in the newHtml variable and continue with the second match. If the second match succeeds I insert the viewstate tag just before the closing form tag and set the success variable to true. So only if all operations succeed we can use the modified html, otherwise we will use the original. I make a check:

if ( success )
{
writer.Write( newHtml );
}
else
{
writer.Write( originalHtml );
}

I use the HtmlTextWriter named writer, which we accept as a parameter of the Render method. This method writes the html to the output.

There are several occasions when some of the matches will not succeed and the original html must be rendered. For example when we use Ajax controls where we have partial rendering. In this situation only a part of the page html is rendered and there is no ViewState.

The second step was to optimize the ViewState so now its size is reduced up to 95%. In fact we do not need any more to move it to the bottom because only a small part of it remained. So this solution was just temporary. But if you don’t have enough time to make optimizations you can use this solution.

Using the HyperlinkButton control in Silverlight 2 Beta 1

nraychev — Fri, 30 May 2008 14:13:00 GMT

I published an article about the HyperlinkButton, which you can see here:

HyperlinkButton in Silverlight 2 beta 1

Articles about Button controls in general and the Button control in Silverlight 2 Beta 1

nraychev — Mon, 12 May 2008 08:15:00 GMT

I published two new articles about Silverlight controls today:

The first covers the key features of the ButtonBase class, inherited in all button controls, you can see it here: Button Controls

The second one is dedicated to the Button control. Visit it here: Button Control

Using the Border control in Silverlight 2 Beta 1

nraychev — Thu, 08 May 2008 12:04:00 GMT

I completely forgot to mention my article about the Border control in Silverlight which I published a few weeks ago.

Here it is:

Using the Border control in Silverlight 2 Beta 1

SiteMap and URL Rewriting in ASP.NET 2.0

nraychev — Wed, 23 Apr 2008 09:04:00 GMT

Introduction

A common scenario in web development is when one page shows different content depending on some query parameters. OK, but these query parameters do not look friendly to the user and are neither friendly for the search engines. Here the URL Rewriting comes. We have URL rewriting in SilverlightShow.net sitemap page. Look for example here:

http://www.silverlightshow.net/Sitemap-Articles.aspx

You see that the articles are organized in pages and when clicking on “Older Articles” or “Newer Articles” the page is changed and the URL looks slightly different. Only the number at the end of the page name is different, for example “Sitemap-Articles-1.aspx” or “Sitemap-Articles-2.aspx”.

The problem

It’s needless to say that all these different URLs are processed by a single ASP.NET page. The problem came when we decided to put an ASP.NET SiteMapPath control. By default it automatically binds using the information provided in the Web.sitemap file. OK, we have the following SiteMap structure:

<?xmlversion="1.0"encoding="utf-8" ?>

<siteMapxmlns="http://schemas.microsoft.com/AspNet/SiteMap-File-1.0" >

<siteMapNodeurl="~/Default.aspx"title="Home" description="Home">

<siteMapNodeurl="~/Sitemap.aspx"title="Sitemap"description="Sitemap">

<siteMapNodeurl="~/Sitemap-News.aspx"title="News"description="News"></siteMapNode>

<siteMapNodeurl="~/Sitemap-Articles.aspx"title="Articles" description="Articles">

<siteMapNodeurl="~/Sitemap-Announcements.aspx"title="Announcements"description="Announcements"></siteMapNode>

<siteMapNodeurl="~/Sitemap-Products.aspx"title="Products"description="Products">

<siteMapNodeurl="~/Sitemap-Controls.aspx"title="Controls"description="Controls"></siteMapNode>

<siteMapNodeurl="~/Sitemap-MediaPlayers.aspx"title="Media Players"description="Media Players"></siteMapNode>

<siteMapNodeurl="~/Sitemap-Games.aspx"title="Games"description="Games"></siteMapNode>

<siteMapNodeurl="~/Sitemap-Charts.aspx"title="Charts"description="Charts"></siteMapNode>

</siteMapNode>

<siteMapNodeurl="~/Sitemap-Tools.aspx"title="Tools"description="Tools"></siteMapNode>

<siteMapNodeurl="~/Sitemap-Moonlight.aspx"title="Moonlight"description="Moonlight"></siteMapNode>

<siteMapNodeurl="~/Sitemap-Demos.aspx"title="Demos"description="Demos"></siteMapNode>

<siteMapNodeurl="~/Sitemap-Learn.aspx"title="Learn"description="Learn">

<siteMapNodeurl="~/Sitemap-Videos.aspx"title="Videos"description="Videos"></siteMapNode>

<siteMapNodeurl="~/Sitemap-Presentations.aspx"title="Presentations"description="Presentations"></siteMapNode>

<siteMapNodeurl="~/Sitemap-Tutorials.aspx"title="Tutorials"description="Tutorials"></siteMapNode>

<siteMapNodeurl="~/Sitemap-Resources.aspx"title="Resources"description="Resources"></siteMapNode>

<siteMapNodeurl="~/Sitemap-Samples.aspx"title="Samples"description="Samples"></siteMapNode>

<siteMapNodeurl="~/Sitemap-QuickStarts.aspx"title="QuickStarts"description="QuickStarts"></siteMapNode>

<siteMapNodeurl="~/Sitemap-TipsandTricks.aspx"title="Tips and Tricks"description="Tips and Tricks"></siteMapNode>

</siteMapNode>

<siteMapNodeurl="~/Sitemap-Issues.aspx"title="Issues"description="Issues"></siteMapNode>

<siteMapNodeurl="~/Sitemap-Misc.aspx"title="Misc"description="Misc"></siteMapNode>

</siteMapNode>

<siteMapNodeurl="~/Sitemap-Shows.aspx"title="Shows"description="Shows"></siteMapNode>

</siteMapNode>

</siteMap>

We have the root website node, marked with title “Home” and the sitemap node marked with title “Sitemap”. All child nodes of the “Sitemap” node except the last child (Shows) are processed by a single ASP.NET page. Since the URL is different no matter that all these nodes are in fact one ASP.NET page the SiteMapPath works the way it has to work. For example if we are on the following URL:

http://www.silverlightshow.net/Sitemap-Articles.aspx

Our SiteMapPath is rendered the following way:

If you look at our Web.sitemap file you will see that it works fine. Till now everything is OK, but imagine that we want to open the last page in the Articles page, which is on the following URL:

http://www.silverlightshow.net/Sitemap-Articles-1.aspx

It works on SilverlightShow.net because we have made it work but in common scenario it wouldn’t work. No SiteMapPath would be shown because in the Web.sitemap we don’t have a node with url="~/Sitemap-Articles-1.aspx". You can always say that we can add this node too but in our case lots of articles are added to the site every day and the pages become more and more. I don’t like the option of checking for new pages every day and updating the Web.sitemap file.

The solution

The solution is to attach to the SiteMap.SiteMapResolve in the OnLoad handler of the page that processes the request where paging is needed.

We have the following code in the code behind of our page:

protected override void OnLoad( EventArgs e )

{

base.OnLoad( e );

SiteMap.SiteMapResolve += new SiteMapResolveEventHandler( this.ConstructSiteMap );

Note: You can do the same in the Page_Load method if your ASP.NET page is marked with: AutoEventWireup="true". I’m overriding the OnLoad event handler because it is faster :)

Note: SiteMap class is located in the System.Web namespace and is an in-memory representation of the navigation structure of the website. It is used by the SiteMapPath control.

Here is the handler for the SiteMapResolve event.

private SiteMapNode ConstructSiteMap( Object sender, SiteMapResolveEventArgs e )

{

SiteMapNode currentNode;

if ( SiteMap.CurrentNode == null )

{

currentNode = e.Provider.FindSiteMapNode( "~/Sitemap-Articles.aspx " );

}

else

{

currentNode = SiteMap.CurrentNode.Clone( true );

}

return currentNode;

}

In our case if the URL is with paging it is not found in the Web.sitemap file and that’s why the SiteMap.CurrentNode property will be null. This causes the SiteMapPath control to disappear. OK, now we check if this property of the SiteMap is null and if it is we just create a SiteMapNode using the current provider’s SiteMapProvider.FindSiteMapNode method giving the URL without paging. Note that we surely will know the URL that must be given to the FindSiteMapNode method because we are in the page which processes the request. If this property is not null we just clone it. The return value of our handler will be the SiteMapNode which will be used to render the SiteMapPath control.

This is a better solution than updating the Web.sitemap file every day.

Additional Issues and solutions

I found out that the SiteMap class has a strange way of caching. For example if we go to: http://www.silverlightshow.net/Sitemap-Controls.aspx our SiteMapPath will look like this:

After that we are going to http://www.silverlightshow.net/Sitemap-Articles.aspx and our SiteMapPath is normal:

But the problem comes when we go through the pages. If we hadn’t find a solution our SiteMapPath path would look this way, no matter that we are on the Articles page and not on the Controls page:

This behavior is as strange as our solution. It seems that the SiteMap remembered that when last time the CurrentNode was null we made it “~/Sitemap-Controls.aspx” and when we are on Articles page and this node is again null it uses the previous value from Controls. As I told you our solution is also strange but works :) We are putting our page path in variable instead of literal:

currentNode = e.Provider.FindSiteMapNode( this.currentPagePath );

Our variable of type string currentPagePath contains for example the following value “~/Sitemap-Games.aspx” for the following page: http://www.silverlightshow.net/Sitemap-Games.aspx. The behavior is exactly the same. But if we make this variable null just after our page is unloaded no caching takes place:

protected override void OnUnload( EventArgs e )

{

base.OnUnload( e );

this.currentPagePath = null;

}

Note: In our case our Controls and Articles pages are processed by a single ASP.NET page. But the caching behavior of the SiteMap takes place even these two URLs are processed by different ASP.NET pages. Our solution works for our Shows page which is different ASP.NET page. You just must make the variable which contains the current node path null on both places.

Using the GridSplitter control in Silverlight 2 Beta 1

nraychev — Tue, 15 Apr 2008 14:30:00 GMT

I wrote a little article about using the GridSplitter control.

You can see it here:

GridSplitter Article

I also wrote another article in response of a guy who asked me about how the Canvas control deals with the Measure/Arrange process when it is laid out by a parent Panel.

Here it is:

Canvas and Measure/Arrange

A few articles about layout controls in Silverlight 2 Beta 1.

nraychev — Wed, 09 Apr 2008 08:21:00 GMT

Hi to all :)

As a first post in this blog I'd like to present the articles about Silverlight which we published this week. They describe how to use the layout controls in Silverlight 2 Beta 1 and can be used as tutotials:

Yolu can see them here:

Layout controls in Silverlight 2 Beta 1

Using the Canvas control in Silverlight 2 Beta 1

Using the StackPanel control in Silverlight 2 Beta 1

Using the Grid control in Silverlight 2 Beta 1

DataGridView Extension 1.1.1 was released today.

iiordanov — Fri, 29 Feb 2008 16:13:00 GMT

DataGridView Extension 1.1.1 was published today and the full functional free version can be downloaded from here.
List of the fixed issues included in this new version are:

Added rows to unbound DataGridView control are not shown - described in this post;
Export of DataGridView using API results in black color of some of the exported cells;
Improved multithread operations when exporting;
Changes in API comments on classes, methods, properties, etc;
Other bug fixes.

What more has changed is that now the source code of the DataGridView Extension is available for sell from here.

CodeCamp Bulgaria

estoychev — Thu, 07 Feb 2008 11:40:16 GMT

The developer's community in Bulgaria organizes the first Code Camp on 15/16th of February 2008. I'm glad to see that such initiatives are held in my country as well. I'm sure it is going to be fun and this will be the first of many upcoming camps.

There will be 7 sessions:

Pingback and Trackback enable your web application
Multicore architectures and programming
CIFactory - continues integration on crack
Mootools
Aggregator How-To
Creating multiplatform .NET applications using Mono

I'm going to speak in the first one - Pingback and Trackback enable your web application. You can find more information on the official site - http://codecamp.sofiadev.org

Meet you there.

Interactive Silverlight Voting Control

idragoev — Wed, 05 Dec 2007 14:43:00 GMT

As you might know, we at CompletIT are behind the SilverlightShow.net - the independent Silverlight community site. Also, the last few weeks we've published several articles (with source code included) just to show how easy is to create nice stuff with Silverlight 1.1.

I also decided to write an article based on simple interactive voting control. The purpose of this control is to show the current results for certain vote. The site visitors can give their vote simply by clicking on the option result they like and the results are automatically updated.

We will continue publishing articles with source code. We hope such examples are helpful for the developers.

You can submit your own article Silverlight on SilverlightShow.net - just click here.

Silverlight 1.1 Tools Alpha - VS Orcas Beta 2 to VS2008 RTM migration issues

estoychev — Tue, 04 Dec 2007 09:10:27 GMT

Last week Silverlight 1.1 Tools Alpha for VS 2008 RTM were released and as a developer working with Silverlight I run to install them on my fresh new copy of VS 2008 RTM. The installation went without any problems, but unfortunately after trying to create a new Silverlight project (same for class library) I got a popup error saying:

"The project file 'C:\Users\estoychev\AppData\Local\Temp\zhxiyguv.4rr\Temp\SilverlightProject1.csproj' cannot be opened. The project type is not supported by this installation."

Puff. I tried to google about this error message but I got no helpful results. I only noticed that a guy commented on the ScottGu's blog with the same problem. Scott kindly replied to this guy to mail him and he would attach someone to help for this problem. I followed his advice and wrote to him. The next day I received an answer from Bill Hiebert guiding me how to resolve my problem. The simple step you should take is the following:

Open a Visual Studio Command prompt and type "devenv /resetskippkgs".

Then try to create a new Silverlight project. This solution does work for me. I hope it also works for you. Thanks Bill ;)

DataGridView Extension 1.1 Installation Update

iiordanov — Fri, 30 Nov 2007 10:08:00 GMT

DataGridView Extension's installation and archive for download were updated.
List of the fixed issues included in the new update:

Improved error handling in the Xml persistence;
Fixed a bug in themes import functionality;
Update of ‘Developers' guide’ and ‘End User Manual’;
Fixed bug in Pdf export font mapping – the Extension could not embed in the generated pdf document font which is a part of Font Type Collection file. Instead of that a default font is used;
Other small fixes and improvements.

DataGridView Extension 1.1 hit the streets with improvements, print and export to Pdf.

iiordanov — Sat, 17 Nov 2007 18:58:00 GMT

The new version of DataGridView Extension 1.1 has been relesed on time. In the new version you will find printing functionality, export to Pdf, many improvements and bug-fixes. You can download it from here or see the change log.

DataGridView Extension 1.1 will be released on the 13th of November 2007.

iiordanov — Fri, 02 Nov 2007 15:01:00 GMT

We are proud to announce that DataGridView Extension 1.1 will be released on the 13th of November 2007. This new version will contain new functionalities (such as Export & Import of themes, Print, Export to Pdf, UI Security and others) as well as fixes of issues reported by our users (thank you guys!). Developers guide will be also available for download, describing how to use, integrate, change and control the extension and its features in your applications.

CompletIT at DevReach, Sofia, Bulgaria 1-2 October, 2007

idragoev — Mon, 08 Oct 2007 15:36:00 GMT

At the beginning of October I have visited DevReach - the premier conference for Microsoft technologies in South Eastern Europe. I was on several lectures about MS SQL:

What's New in SQL Server 2008 for Developers - by Vladi Tchalkov;
T–SQL Querying: Tips and Techniques (With SQL 2008 features too) by Stephen Forte;
Lino Does LINQ by Lino Tadros;
Being Smart About Database Design by Vladi Tchalkov,
100 Years of Transaction Solitude...Transactions and isolation levels by Ami Levin;
SQL Server Service Broker - Your Gateway to the World of Transactional Asynchronicity by Ami Levin;
Security and .NET by Hadi Hariri;
Silverlight, Flash on Steroids by Lino Tadros.

What I appreciated most is the fact, that I had the chance to discuss different topics with the speakers. Most of them are experienced, well known in the community, with knowledge about the cutting-edge MS technologies.

I’m looking forward to meeting the guys again.

DGV Extension's installation and archive for download were updated #2

iiordanov — Sat, 15 Sep 2007 08:13:00 GMT

Now you can download our latest installation\archive with improved export to Excel.
An issue was found and described by one of our users in the following topic.

Please note that if you already have DataGridView Extension downloaded you do not need to download it again but just the assembly 'DGVEExcelExporter.dll' and replace the old one you already have.

SilverlightShow.net - Silverlight Community

estoychev — Sat, 01 Sep 2007 15:12:00 GMT

Today we've published our first beta of SilverlightShow. It is a website that provides regular aggregation and classification of the information related to Silverlight available all over the Internet. We will get interviews, make video/audio/screen casts, write articles, provide samples; we will try to bring to you the hottest articles around Silverlight. As it is still a beta version there are no benefits to be a member of the community but soon we will provide functionalities to publish your own articles.

Currently we aggregate news from different sources - blogs, user groups, etc. We categorize the information carefully and let you see only the valuable pieces of it. Probably now you use RSS/Atom feeds or Google Alerts or Google Blog Search to stay in touch with the latest news around Silverlight. Yes, we also use these 'tools'. We also check the official Microsoft Silverlight Community site. We know about all of them. But we strongly believe that we can offer you more - a better experience to stay tuned with Silverlight.

I hope you will see in SilverlightShow a great place to learn and discuss things about Silverlight.

ASP.NET 2.0 issues: Validation of viewstate MAC failed

estoychev — Fri, 31 Aug 2007 11:44:00 GMT

Have you ever experienced such error? Well, today I did. It is not easy to get it - you have to browse too quickly trough pages (or in one page) and click buttons (causing postback). Yep, sounds strange. The point is that if you have a page, with lets say just a text box and a button, and you push that button quickly you will probably get this error - especially if you do it with slow connection or at least not on your local machine.

I would reccommend reading this thread in ASP.NET forums if you want to learn more about this error and want a solution (or a workaround).

DGV Extension's installation and archive for download were updated

iiordanov — Fri, 31 Aug 2007 11:32:00 GMT

Now you can download our latest installation\archive with improved file structure and sample project in C#.

DataGridView Extension 1.0. Release

idragoev — Fri, 17 Aug 2007 12:27:00 GMT

When Microsoft released .NET framework 2.0 the DataGrid control was replaced by DataGridView, which allows the developers to control better the way the data is presented by creation of much more user friendly views, but even in DataGridView control there is missing functionality.

And here is where the DataGridView Extension component comes, it is absolutely free and extends the functionality of the standard DataGridView control by adding themes support, searching data, export to Excel and HTML, etc.

Moreover, DataGridView Extension allow end-users to control the whole appearance at run time – columns size and order, formatting, colors, borders, etc.

The developers can easily integrate DataGridView Extension in their existing application in two simple steps:

Add reference to DataGridViewExtension.dll and the dll for exporting to Excel (DGVEExcelExporting.dll) and to HTML (DGVEHtmlExporting.dll) if needed.
Drag & drop DataGridView Extension Component on your root container from the toolbox then select the grid you wish to manage and set the value of its property ‘IsManagedByExtension’ to true

As a conclusion we can say that the DataGridView Extension brings direct, visible, benefits to the applications’ end-users by giving them control over the presentation of the data at run-time as well as export to external well known formats.

You can learn more about DataGridView Extension here.