My C# program threw an exception from the following method: SizeF size = Graphics.MeasureString( text, font ); Unfortunately, the exception’s message was rather obscure: “Parameter is invalid.”  After an investigation, I discovered the error occurred because the font had been previously disposed.  Unfortunately, the Font class does not have the typical IsDisposed property, so there Related posts: Change Font Size Convert Between Synchronous and Asynchronous Change Font Style

While surfing the web you may have come across websites with images and other multimedia content that, when clicked, were displayed in a floating window that hovered above the web page. Perhaps it was a page that showed a series of thumbnail images of products for sale, where clicking on a thumbnail displayed the full sized image in a floating window, dimming out the web page behind it. Have you ever wondered how this was accomplished or whether you could add such functionality to your ASP.NET website? In years past, adding such rich client-side functionality to a website required a solid understanding of JavaScript and the “eccentricities” of various web browsers. Today, thanks to powerful JavaScript libraries like jQuery , along with an active developer community creating plugins and tools that integrate with jQuery, it’s possible to add snazzy client-side behaviors without being a JavaScript whiz. This article shows how to display text, images, and other multimedia content in a floating window using FancyBox , a free client-side library. You’ll learn how it works, see what steps to take to get started using it, and explore a number of FancyBox demos. There’s also a demo available for download that shows using FancyBox to display both text and images in a floating window in an ASP.NET website. Read on to learn more! Read More >

Cascading Style Sheets , or CSS, is a syntax used to describe the look and feel of the elements in a web page. CSS allows a web developer to separate the document content – the HTML, text, and images – from the presentation of that content. Such separation makes the markup in a page easier to read, understand, and update; it can result in reduced bandwidth as the style information can be specified in a separate file and cached by the browser; and makes site-wide changes easier to apply. For a great example of the flexibility and power of CSS, check out CSS Zen Garden . This website has a single page with fixed markup, but allows web developers from around the world to submit CSS rules to define alternate presentation information. Unfortunately, certain aspects of CSS’s syntax leave a bit to be desired. Many style sheets include repeated styling information because CSS does not allow the use of variables. Such repetition makes the resulting style sheet lengthier and harder to read; it results in more rules that need to be changed when the website is redesigned to use a new primary color. Specifying inherited CSS rules, such as indicating that a elements (i.e., hyperlinks) in h1 elements should not be underlined, requires creating a single selector name, like h1 a . Ideally, CSS would allow for nested rules, enabling you to define the a rules directly within the h1 rules. .LESS is a free, open-source port of Ruby’s LESS library

As developers, we all make assumptions when programming. Perhaps the biggest assumption we make is that those libraries and tools that ship with the .NET Framework are the best way to accomplish a given task. For example, most developers assume that using ASP.NET’s Membership system is the best way to manage user accounts in a website (rather than rolling your own user account store). Similarly, creating a Web Reference to communicate with a web service generates markup that auto-creates a proxy class , which handles the low-level details of invoking the web service, serializing parameters, and so on.

Twitter is a popular social networking web service for writing and sharing short messages. These tidy text messages are referred to as tweets and are limited to 140 characters. Users can leave tweets and follow other users directly from Twitter’s website or by using the Twitter API. Twitter’s API makes it possible to integrate Twitter with external applications. For example, you can use the Twitter API to display your latest tweets on your blog. A mom and pop online store could integrate Twitter such that a new tweet was added each time a customer completed an order. And ELMAH , a popular open-source error logging library, can be configured to send error notifications to Twitter. Twitter’s API is implemented over HTTP using the design principles of Representational State Transfer (REST) . In a nutshell, inter-operating with the Twitter API involves a client – your application – sending an XML-formatted message over HTTP to the server – Twitter’s website. The server responds with an XML-formatted message that contains status information and data. While you can certainly interface with this API by writing your own code to communicate with the Twitter API over HTTP along with the code that creates and parses the XML payloads exchanged between the client and server, such work is unnecessary since there are many community-created Twitter API libraries for a variety of programming frameworks. This article shows how to integrate Twitter with an ASP.NET website using the Twitterizer library, which is a free, open-source .NET library for working with the Twitter API. Specifically, this article shows how to retrieve your latest tweets and how to post a tweet using Twitterizer

The Release Candidate (RC) for Visual Studio 2010 and .NET Framework 4.0 is now available to the public.  The biggest change from Beta 2 is a major improvement to Visual Studio performance, specifically as it relates to loading solutions, typing, building and debugging.  The RC includes a “go-live license” for companies that wish to deploy Related posts: Visual Studio 2010 and .NET 4.0 Beta 2 Documentation Available for .NET Framework 4 and Visual Studio 2010 Visual Studio 2010 Beta 1 Now Available for MSDN Subscribers

In most usage scenarios, the data displayed in a Microsoft Chart control comes from some dynamic source, such as from a database query. The appearance of the chart can be modified dynamically, as well; past installments in this article series showed how to programmatically customize the axes, labels, and other appearance-related settings. However, it is possible to statically define the chart’s data and appearance strictly through the control’s declarative markup. One of the demos examined in the Getting Started article rendered a column chart with seven columns whose labels and values were defined statically in the <asp:Series> tag’s <Points> collection. Given this functionality, it should come as no surprise that the Microsoft Chart Controls also support serialization . Serialization is the process of persisting the state of a control or an object to some other medium, such as to disk. Deserialization is the inverse process, and involves taking the persisted data and recreating the control or object. With just a few lines of code you can persist the appearance settings, the data, or both to a file on disk or to any stream. Likewise, it takes just a few lines of codes to reconstitute a chart from the persisted information.

Like every Web control in the ASP.NET toolbox, the GridView includes a variety of style-related properties, including CssClass , Font , ForeColor , BackColor , Width , Height , and so on. The GridView also includes style properties that apply to certain classes of rows in the grid, such as RowStyle , AlternatingRowStyle , HeaderStyle , and PagerStyle . Each of these meta-style properties offer the standard style properties ( CssClass , Font , etc.) as subproperties. In ASP.NET 4.0, Microsoft added four new style properties to the GridView control: SortedAscendingHeaderStyle , SortedAscendingCellStyle , SortedDescendingHeaderStyle , and SortedDescendingCellStyle . These four properties are meta-style properties like RowStyle and HeaderStyle , but apply to column of cells rather than a row. These properties only apply when the GridView is sorted – if the grid’s data is sorted in ascending order then the SortedAscendingHeaderStyle and SortedAscendingCellStyle properties define the styles for the column the data is sorted by. The SortedDescendingHeaderStyle and SortedDescendingCellStyle properties apply to the sorted column when the results are sorted in descending order. These four new properties make it easier to customize the appearance of the column by which the data is sorted. Using these properties along with a touch of Cascading Style Sheets (CSS) it is possible to add up and down arrows to the sorted column’s header to indicate whether the data is sorted in ascending or descending order. Likewise, these properties can be used to shade the sorted column or make its text bold.

In the .NET Framework 3.5 SP1, Microsoft introduced ASP.NET Routing, which decouples the URL of a resource from the physical file on the web server. With ASP.NET Routing you, the developer, define routing rules map route patterns to a class that generates the content. For example, you might indicate that the URL Categories/ CategoryName maps to a class that takes the CategoryName and generates HTML that lists that category’s products in a grid. With such a mapping, users could view products for the Beverages category by visiting www.yoursite.com/Categories/Beverages . In .NET 3.5 SP1, ASP.NET Routing was primarily designed for ASP.NET MVC applications, although as discussed in Using ASP.NET Routing Without ASP.NET MVC it is possible to implement ASP.NET Routing in a Web Forms application, as well. However, implementing ASP.NET Routing in a Web Forms application involves a bit of seemingly excessive legwork. In a Web Forms scenario we typically want to map a routing pattern to an actual ASP.NET page. To do so we need to create a route handler class that is invoked when the routing URL is requested and, in a sense, dispatches the request to the appropriate ASP.NET page

Do you need help convincing your boss that your company needs to upgrade to Visual Studio 2010?  Or perhaps you are looking for additional ammo in your .NET vs. Java religious wars with your programming colleagues? Microsoft has produced a Silverlight-based “Myth Busting Matrix” for Visual Studio.  This nifty web tool details the benefits of upgrading Related posts: Microsoft Unveils Visual Studio 2010 and .NET 4.0 Visual Studio 2010 and .NET 4.0 Beta 2 Documentation Available for .NET Framework 4 and Visual Studio 2010

Zain Naboulsi, a Senior Developer Evangelist at Microsoft, has started the “Tip of the Day” series for Visual Studio 2010, taking the reins from Sara Ford. Visual Studio 2010 Tip of the Day Related posts:Microsoft Unveils Visual Studio 2010 and .NET 4.0Visual Studio 2010 Beta 1 Now Available for MSDN SubscribersVisual Studio 2010 and .NET 4.0 Beta Related posts: Microsoft Unveils Visual Studio 2010 and .NET 4.0 Visual Studio 2010 Beta 1 Now Available for MSDN Subscribers Visual Studio 2010 and .NET 4.0 Beta 2

Filtering Database Data with Parameters , an earlier installment in this article series, showed how to filter the data returned by ASP.NET’s data source controls. In a nutshell, the data source controls can include parameterized queries whose parameter values are defined via parameter controls. For example, the SqlDataSource can include a parameterized SelectCommand , such as: SELECT * FROM Books WHERE Price > @Price . Here, @Price is a parameter ; the value for a parameter can be defined declaratively using a parameter control . ASP.NET offers a variety of parameter controls, including ones that use hard-coded values, ones that retrieve values from the querystring, and ones that retrieve values from session, and others. Perhaps the most useful parameter control is the ControlParameter, which retrieves its value from a Web control on the page. Using the ControlParameter we can filter the data returned by the data source control based on the end user’s input. While the ControlParameter works well with most types of Web controls, it does not work as expected with the CheckBoxList control. The ControlParameter is designed to retrieve a single property value from the specified Web control, but the CheckBoxList control does not have a property that returns all of the values of its selected items in a form that the CheckBoxList control can use. Moreover, if you are using the selected CheckBoxList items to query a database you’ll quickly find that SQL does not offer out of the box functionality for filtering results based on a user-supplied list of filter criteria. The good news is that with a little bit of effort it is possible to filter data based on the end user’s selections in a CheckBoxList control.

The previous installment in this ongoing article series showed how to configure the DataPager control to generate an SEO-friendly paging interface. By default, the DataPager renders its paging interface as a series of Buttons, LinkButtons, or ImageButtons that, when clicked, trigger a postback. The problem with postbacks is that they are not crawled by search engine spiders, meaning that with the default behavior only the first page of data will make it into the search engines’ indexes. Fortunately, the DataPager’s paging interface can be configured to include the page number in the querystring. When configured this way, the DataPager renders its paging interface using hyperlinks with URLs like Products.aspx?Page= PageNumber .

The GridView, FormView, and DetailsView controls all contain built-in paging functionality. By setting a few properties, it’s possible to have any of these controls automatically include a paging interface. The ListView, however, does not include built-in paging functionality. Instead, Microsoft decoupled the paging logic from the ListView and moved it into a separate Web control – the DataPager. Paging Through Data with the ListView and DataPager Controls , an earlier article in this series, explored how to use the DataPager to implement a paging interface for the ListView. By default, the DataPager renders Buttons, LinkButtons, or ImageButtons in the paging interface for the Next, Previous, First, Last, and numeric page number buttons. When clicked, these buttons cause a postback, at which point the appropriate set of records are bound to the ListView. Unfortunately, search engines cannot crawl a site using postbacks; instead, they rely on links they find on your site. Consequently, a search engine will only index the first page of data displayed by a ListView, because it cannot reach the subsequent pages.

The end of the year is upon us, 2009 is about to be in the books. When closing out a year I like to take a look back at the articles I wrote over the year and see which ones resonated the most with readers. Which ones generated the most reader emails? Which ones were read the most? Such a retrospective analysis highlights what content was of most interest to developers in the trenches, and this data is used to guide article topics in the new year. While cataloging this year’s most popular articles I thought others might find the data interesting. Such a “Best Of 2009″ list would give both regular and new readers a chance to discover (or rediscover) the most favored content from the year. So here it is – a list and synopsis of the 2009’s most popular articles on 4GuysFromRolla.com. Read More >

Charts are typically used to provide a static snapshot of data. The chart’s underlying data might be based on various user inputs, but in the end the chart, once rendered, represents the end of the reporting workflow. However, other scenarios allow for a more interactive user experience. For example, in the Creating Drill Down Reports article we looked at how to configure the Chart control to allow the user to drill into a particular data point. Specifically, the demo contained a column chart showing the number of products in each category in the Northwind database. Clicking on a column whisked the user to a new page that details about the products in that category. Also, in certain situations the data populating the chart might be arriving from a sensor or some other source that is constantly being updated. In that case, we might want a real time chart whose data is periodically (and automatically) refreshed to show the latest data

Over the years I’ve worked on a number of projects where users could customize some aspect of the site. One such application surveyed a group of employees with and then made recommendations on how to best organize the employees into teams. Companies could buy a certain number of surveys and then direct their employees to the site to complete the survey. Before sending their employees to the site, a company could adjust the survey’s look and feel, uploading their own logo and choosing background and foreground colors, among other customizations. A common requirement for such customizable websites is the ability for the user to select one or more colors

Whenever a browser makes an HTTP request to a web server, it sends along several HTTP headers . These HTTP Headers are used to provide the web server with information to assist with handling the request. For instance, if the browser supports compression it will send along an Accept-Encoding HTTP Header, which lets the web server know what compression algorithms the browser can work with. Any cookies previously set by the web server are sent from the browser back to the server via the Cookies HTTP Header. The browser also sends the User-Agent HTTP Header, which the web server can parse to determine the browser (IE, Firefox, Safari, etc.), the version number, the operating system, and other information. Similarly, the web server includes a number of HTTP Headers when it sends back the contents of the requested resource. These headers are used by the browser to determine how to render the content and for how long to cache the content.

XML is an increasingly popular way to encode documents, data, and electronic messages. There are a number of ways to programmatically create, modify, and search XML files. Since its inception, the .NET Framework’s System.Xml namespace has included classes for programmatically working with XML documents. For instance, the XmlReader and XmlWriter classes offer developers a means to read from or write to XML files in a fast, forward-only manner, while the XmlDocument class allows developers to work with an XML document as an in-memory tree representation. LINQ to XML is a new set of XML-related classes in the .NET Framework (found in the System.Xml.Linq namespace ), which enable developers to work with XML documents using LINQ’s features, syntax, and semantics. Compared to .NET’s existing XML APIs, LINQ to XML is a simpler, easier to use API. For a given task, LINQ to XML code is typically shorter and more readable than code that uses the XmlDocument or XmlReader / XmlWriter classes.

F9 Group wanted to show support for California’s Air Resource board and all the children at Topeka Drive Elementary, which includes general education students, special needs students ( Visually Impaired and Specific Learning Disabilities) and GATE students.

F9 Group wishes the students and faculty at Topeka Drive Elementary a successful school year.

The Microsoft Chart controls make it easy to take data from a database or some other data store and present it as a chart. As discussed in Plotting Chart Data , the Chart controls offer a myriad of ways to get data into a chart. You can add the data programmatically, point-by-point, or you can bind an ADO.NET DataTable directly to the Chart. You can even use declarative data source controls, like the SqlDataSource or ObjectDataSource controls. In addition to converting your specified data points into a chart image, the Chart controls also include a wealth of statistical formulae that you can use to analyze the plotted data. For example, with a single line of code you determine the mean (average) value for data in a particular series. Likewise, with one line of code you can get the median, variance, or standard deviation. These values can be displayed as text on the page or as a stripe line on the chart itself

The SqlBulkCopy class provides a mechanism for efficiently importing large amounts of data into a Microsoft SQL Server database. Compared to importing data by executing one INSERT statement for each record to import, SqlBulkCopy is noticeably faster when importing thousands (or more) records. In a nutshell, importing data using SqlBulkCopy entails creating a SqlBulkCopy object, specifying the destination database and table, and providing the data to import in the form of a DataTable , DataRow , or DataReader. In Using SqlBulkCopy To Perform Efficient Bulk SQL Operations we looked at how to use SqlBulkCopy to programmatically import data from an uploaded Excel spreadsheet into a SQL Server database. While Using SqlBulkCopy To Perform Efficient Bulk SQL Operations showed how to use the SqlBulkCopy class, it did not explore how SqlBulkCopy imports fare in the face of an error. What happens if, when importing a total of 10,000 records, an error occurs when importing record number 501?

Many of the web applications I help build can be classified as in-production line of business applications that receive frequent and ongoing feature enhancements. Typically, these applications have dozens if not hundreds of users who rely on the site each and every day to accomplish tasks necessary to keep the company running smoothly. Every week or so the latest code is deployed to the production servers, bringing with it bug fixes and, very often, new features or changes to existing features. One challenge I’ve bumped into when working on such applications is how to best alert users of the new features and the changes to existing features?

Each series in a chart is composed of a set of data points, which are modeled via the DataPoint class. For most chart types, the two key attributes of a data point are its X and Y value. For example, in a line chart the X value indicates the position of the data point along the X axis, while the Y value represents the position of the data point along the Y axis. Ditto for a column chart, although it may help to think of the Y value as the height of the column.

The second beta version of Visual Studio 2010 and Microsoft .NET Framework v4.0 are now available.  VS 2010 and .NET 4.0 deliver significant new capabilities and improvements.  The Beta 2 release was focused on performance, stability, and the integration of the overall feature set.  The development team is awaiting our feedback on the product and Related posts: Visual Studio 2010 Beta 1 Now Available for MSDN Subscribers Visual Studio "Orcas" and .NET 3.5 Beta Available Microsoft Unveils Visual Studio 2010 and .NET 4.0