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My Favorite New Features in Visual Studio 2010

On Tuesday, April 13th, Microsoft released Visual Studio 2010 and the .NET Framework 4.0 (which includes ASP.NET 4.0). To get started with Visual Studio 2010 you can either download a trial version of one of the commercial editions or you can go grab the free Visual Web Developer 2010 Express Edition. The Visual Studio 2010 user experience is noticeably different than with previous versions. Some of the changes are cosmetic - gone is the decades-old red and orange color scheme, having been replaced with blues and purples - while others are more substantial. For instance, the Visual Studio 2010 shell was rewritten from the ground up to use Microsoft's Windows Presentation Foundation (WPF). In addition to an updated user experience, Visual Studio introduces an array of new features designed to improve developer productivity. There are new tools for searching for files, types, and class members; it's now easier than ever to use IntelliSense; the Toolbox can be searched using the keyboard; and you can use a single editor - Visual Studio 2010 - to work on . This article explores some of the new features in Visual Studio 2010. It is not meant to be an exhaustive list, but rather highlights those features that I, as an ASP.NET developer, find most useful in my line of work. Read on to learn more! Read More >

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Improving CSS With .LESS

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. LESS (and .LESS, by extension) is a parser that allows web developers to create style sheets using new and improved language features, including variables, operations, mixins, and nested rules. Behind the scenes, .LESS converts the enhanced CSS rules into standard CSS rules. This conversion can happen automatically and on-demand through the use of an HTTP Handler, or done manually as part of the build process. Moreover, .LESS can be configured to automatically minify the resulting CSS, saving bandwidth and making the end user's experience a snappier one. This article shows how to get started using .LESS in your ASP.NET websites. Read on to learn more! Read More >

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Formatting Dates, Times and Numbers in ASP.NET

Formatting is the process of converting a variable from its native type into a string representation. Anytime you display a DateTime or numeric variables in an ASP.NET page, you are formatting that variable from its native type into some sort of string representation. How a DateTime or numeric variable is formatted depends on the culture settings and the format string. Because dates and numeric values are formatted differently across cultures, the .NET Framework bases its formatting on the specified culture settings. By default, the formatting routines use the culture settings defined on the web server, but you can indicate that a particular culture be used anytime you format. In addition to the culture settings, formatting is also affected by a format string, which spells out the formatting details to apply. The .NET Framework contains a bounty of format strings. There are standard format strings, which are typically a single letter that applies detailed formatting logic. For example, the "C" format specifier will format a numeric type as a currency value; the "Y" format specifier displays the month name and four-digit year of the specified DateTime value. There are also custom format strings, which display a apply a very specific formatting rule. These custom format strings can be put together to build more intricate formats. For instance, the format string "dddd, MMMM d" displays the full day of the week name followed by a comma followed by the full name of the month followed by the day of the month. For more involved formatting scenarios, where neither the standard or custom format strings cut the mustard, you can always create your own formatting extension methods. This article explores the standard format strings for dates, times and numbers and includes a number of custom formatting methods I've created and use in my own projects. There's also a demo application you can download that lets you specify a culture and then shows you the output for the standard format strings for the selected culture. Read on to learn more! Read More >

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Optimize Images Using the ASP.NET Sprite and Image Optimization Framework

The HTML markup of a web page includes the page's textual content, semantic and styling information, and, typically, several references to external resources. External resources are content that is part of web page, but are separate from the web page's markup - things like images, style sheets, script files, Flash videos, and so on. When a browser requests a web page it starts by downloading its HTML. Next, it scans the downloaded HTML for external resources and starts downloading those. A page with many external resources usually takes longer to completely load than a page with fewer external resources because there is an overhead associated with downloading each external resource. For starters, each external resource requires the browser to make an HTTP request to retrieve the resource. What's more, browsers have a limit as to how many HTTP requests they will make in parallel. For these reasons, a common technique for improving a page's load time is to consolidate external resources in a way to reduce the number of HTTP requests that must be made by the browser to load the page in its entirety. This article examines the free and open-source ASP.NET Sprite and Image Optimization Framework, which is a project developed by Microsoft for improving a web page's load time by consolidating images into a sprite or by using inline, base-64 encoded images. In a nutshell, this framework makes it easy to implement practices that will improve the load time for a web page that displays several images. Read on to learn more! Read More >

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Accessing Server-Side Data from Client Script: Using WCF Services with jQuery and the ASP.NET Ajax Library

Today's websites commonly exchange information between the browser and the web server using Ajax techniques - the browser executes JavaScript code typically in response to the page loading or some user action. This JavaScript makes an asynchronous HTTP request to the server. which then processes the request and, perhaps, returns data that the browser can then seamlessly integrate into the web page. Two earlier articles - Accessing JSON Data From an ASP.NET Page Using jQuery and Using Ajax Web Services, Script References, and jQuery, looked at using both jQuery and the ASP.NET Ajax Library on the browser to initiate an Ajax request and both ASP.NET pages and Ajax Web Services as the entities on the web server responsible for servicing such Ajax requests. This article continues our examination of techniques for implementing lightweight Ajax scenarios in an ASP.NET website. Specifically, it examines how to use the Windows Communication Foundation, or WCF, to serve data from the web server and how to use both the ASP.NET Ajax Library and jQuery to consume such services from the client-side. Read on to learn more! Read More >

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Examining ASP.NET's Membership, Roles, and Profile - Part 18

Membership, in a nutshell, is a framework build into the .NET Framework that supports creating, authenticating, deleting, and modifying user account information. Each user account has a set of core properties: username, password, email, a security question and answer, whether or not the account has been approved, whether or not the user is locked out of the system, and so on. These user-specific properties are certainly helpful, but they're hardly exhaustive - it's not uncommon for an application to need to track additional user-specific properties. For example, an online messageboard site might want to also also associate a signature, homepage URL, and IM address with each user account. There are two ways to associate additional information with user accounts when using the Membership model. The first - which affords the greatest flexibility, but requires the most upfront effort - is to create a custom data store for this information. If you are using the SqlMembershipProvider, this would mean creating an additional database table that had as a primary key the UserId value from the aspnet_Users table and columns for each of the additional user properties. The second option is to use the Profile system, which allows additional user-specific properties to be defined in a configuration file. (See Part 6 for an in-depth look at the Profile system.) This article explores how to store additional user information in a separate database table. We'll see how to allow a signed in user to update these additional user-specific properties and how to create a page to display information about a selected user. What's more, we'll look at using ASP.NET Routing to display user information using an SEO-friendly, human-readable URL like www.yoursite.com/Users/username. Read on to learn more! Read More >

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Filling in PDF Forms with ASP.NET and iTextSharp

The Portable Document Format (PDF) is a popular file format for documents. PDF files are a popular document format for two primary reasons: first, because the PDF standard is an open standard, there are many vendors that provide PDF readers across virtually all operating systems, and many proprietary programs, such as Microsoft Word, include a "Save as PDF" option. Consequently, PDFs server as a sort of common currency of exchange. A person writing a document using Microsoft Word for Windows can save the document as a PDF, which can then be read by others whether or not they are using Windows and whether or not they have Microsoft Word installed. Second, PDF files are self-contained. Each PDF file includes its complete text, fonts, images, input fields, and other content. This means that even complicated documents with many images, an intricate layout, and with user interface elements like textboxes and checkboxes can be encapsulated in a single PDF file. Due to their ubiquity and layout capabilities, it's not uncommon for a websites to use PDF technology. For example, when purchasing goods at an online store you may be offered the ability to download an invoice as a PDF file. PDFs also support form fields, which are user interface elements like textboxes, checkboxes, comboboxes, and the like. These form fields can be entered by a user viewing the PDF or, with a bit of code, they can be entered programmatically. This article is the first in a multi-part series that examines how to programmatically work with PDF files from an ASP.NET application using iTextSharp, a .NET open source library for PDF generation. This installment shows how to use iTextSharp to open an existing PDF document with form fields, fill those form fields with user-supplied values, and then save the combined output to a new PDF file. Read on to learn more! Read More >

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A Look at the GridView's New Sorting Styles in ASP.NET 4.0

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. This article shows how to use these four new properties to style the sorted column. Read on to learn more! Read More >

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Improving CSS With .LESS

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. LESS (and .LESS, by extension) is a parser that allows web developers to create style sheets using new and improved language features, including variables, operations, mixins, and nested rules. Behind the scenes, .LESS converts the enhanced CSS rules into standard CSS rules. This conversion can happen automatically and on-demand through the use of an HTTP Handler, or done manually as part of the build process. Moreover, .LESS can be configured to automatically minify the resulting CSS, saving bandwidth and making the end user's experience a snappier one. This article shows how to get started using .LESS in your ASP.NET websites. Read on to learn more! Read More >

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Using Microsoft's Chart Controls In An ASP.NET Application: Serializing Chart Data

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. This article shows how to use the Microsoft Chart Control's serialization functionality by examining a demo application that allows users to create custom charts, specifying the data to plot and some appearance-related settings. The user can then save a "snapshot" of this chart, which persists its appearance and data to a record in a database. From another page, users can view these saved chart snapshots. Read on to learn more! Read More >

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URL Routing in ASP.NET 4.0

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. For instance, to map a route to a physical file, such as mapping Categories/CategoryName to ShowProductsByCategory.aspx - requires three steps: (1) Define the mapping in Global.asax, which maps a route pattern to a route handler class; (2) Create the route handler class, which is responsible for parsing the URL, storing any route parameters into some location that is accessible to the target page (such as HttpContext.Items), and returning an instance of the target page or HTTP Handler that handles the requested route; and (3) writing code in the target page to grab the route parameters and use them in rendering its content. Given how much effort it took to just read the preceding sentence (let alone write it) you can imagine that implementing ASP.NET Routing in a Web Forms application is not necessarily the most straightforward task. The good news is that ASP.NET 4.0 has greatly simplified ASP.NET Routing for Web Form applications by adding a number of classes and helper methods that can be used to encapsulate the aforementioned complexity. With ASP.NET 4.0 it's easier to define the routing rules and there's no need to create a custom route handling class. This article details these enhancements. Read on to learn more! Read More >

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Accessing and Updating Data in ASP.NET: Filtering Data Using a CheckBoxList

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. This article starts with a look at how to get SQL to filter data based on a user-supplied, comma-delimited list of values. Next, it shows how to programmatically construct a comma-delimited list that represents the selected CheckBoxList values and pass that list into the SQL query. Finally, we'll explore creating a custom parameter control to handle this logic declaratively. Read on to learn more! Read More >

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Dissecting ASP.NET Routing

The ASP.NET Routing framework allows developers to decouple the URL of a resource from the physical file on the web server. Specifically, the developer defines routing rules, which map URL patterns to a class or ASP.NET page that generates the content. For instance, you could create a URL pattern of the form Categories/CategoryName and map it to the ASP.NET page ShowCategoryDetails.aspx; the ShowCategoryDetails.aspx page would display details about the category CategoryName. With such a mapping, users could view category about the Beverages category by visiting www.yoursite.com/Categories/Beverages. In short, ASP.NET Routing allows for readable, SEO-friendly URLs. ASP.NET Routing was first introduced in ASP.NET 3.5 SP1 and was enhanced further in ASP.NET 4.0. ASP.NET Routing is a key component of ASP.NET MVC, but can also be used with Web Forms. Two previous articles here on 4Guys showed how to get started using ASP.NET Routing: Using ASP.NET Routing Without ASP.NET MVC and URL Routing in ASP.NET 4.0. This article aims to explore ASP.NET Routing in greater depth. We'll explore how ASP.NET Routing works underneath the covers to decode a URL pattern and hand it off the the appropriate class or ASP.NET page. Read on to learn more! Read More >

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2010's Most Popular Articles

The end of the year is upon us, 2010 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. I ended last year with a "Best Of" article - see 2009's Most Popular Articles - and decided to continue this tradition. Such "Best Of" articles 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 2010's most popular articles on 4GuysFromRolla.com. Read More >

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Accessing Server-Side Data from Client Script: Accessing JSON Data From an ASP.NET Page Using jQuery

When building a web application, we must decide how and when the browser will communicate with the web server. The ASP.NET WebForms model greatly simplifies web development by providing a straightforward mechanism for exchanging data between the browser and the server. With WebForms, each ASP.NET page's rendered output includes a <form> element that performs a postback to the same page whenever a Button control within the form is clicked, or whenever the user modifies a control whose AutoPostBack property is set to True. On postback, the server sends the entire contents of the web page back to the browser, which then displays this new content. With WebForms we don't need to spend much time or effort thinking about how or when the browser will communicate with the server or how that returned information will be processed by the browser. It just works. While this approach certainly works and has its advantages, it's not without its drawbacks. The primary concern with postback forms is that they require a large amount of information to be exchanged between the browser and the server. Specifically, the browser sends back all of its form fields (including hidden ones, like view state, which may be quite large) and then the server sends back the entire contents of the web page. Granted, there are scenarios where this large quantity of data needs to be exchanged, but in many cases we can use techniques that exchange much less information. However, these techniques necessitate spending more time and effort thinking about how and when to have the browser communicate with the server and intelligently deciding on what information needs to be exchanged. This article, the first in a multi-part series, examines different techniques for accessing server-side data from a browser using client-side script. Throughout this series we will explore alternative ways to expose data on the server so that it can be accessed from the browser using script; we will also examine various tools for communicating with the server from JavaScript, including jQuery and the ASP.NET AJAX library. Read on to learn more! Read More >

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Iron Speed Designer Review

While Visual Studio allows developers to get productive fast by providing great design tools for a UI, it still lacks the ability to do smart layouts, data connections and queries. It is in this area that RAD suite of applications can tremendously boost productivity by abstracting away some of these issues and saving developer time to focus on business intelligence instead of data extraction and presentation. When it comes to RAD application suites for managed web applications, there is non better than Iron Speed Designer. The ease with which you can create a data-centric web application and have different reports of your data within minutes are unparalleled. This review delves into what Iron Speed Designer has to offer as well as some of its limitations. Iron Speed works with .NET 2.0, 3.0, 3.5 and even the latest version .NET 4.0. Read More >

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Sorting and Paging a Grid of Data in ASP.NET MVC

This article is the fifth installment in an ongoing series on displaying a grid of data in an ASP.NET MVC application. Previous articles in this series examined how to sort, page, and filter a grid of data, but none have looked at combining one or more of these features in a single grid. This article and the next one show how to merge these features into a single grid. In particular, this article looks at displaying a grid that can handle both sorting and paging. The subsequent article will examine combining sorting, paging and filtering. Like with its predecessors, this article offers step-by-step instructions and includes a complete, working demo available for download at the end of the article. Read on to learn more! Read More >

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Filtering a Grid of Data in ASP.NET MVC

This article is the fourth installment in an ongoing series on displaying a grid of data in an ASP.NET MVC application. The previous two articles in this series - Sorting a Grid of Data in ASP.NET MVC and Displaying a Paged Grid of Data in ASP.NET MVC - showed how to sort and page data in a grid. This article explores how to present a filtering interface to the user and then only show those records that conform to the filtering criteria. In particular, the demo we examine in this installment presents an interface with three filtering criteria: the category, minimum price, and whether to omit discontinued products. Using this interface the user can apply one or more of these criteria, allowing a variety of filtered displays. For example, the user could opt to view: all products in the Condiments category; those products in the Confections category that cost $50.00 or more; all products that cost $25.00 or more and are not discontinued; or any other such combination. Like with its predecessors, this article offers step-by-step instructions and includes a complete, working demo available for download at the end of the article. Read on to learn more! Read More >

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Integrating Twitter Into An ASP.NET Website

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. Read on to learn more! Read More >

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Creating PDF Documents with ASP.NET and iTextSharp

The Portable Document Format (PDF) is a popular file format for documents. Due to their ubiquity and layout capabilities, it's not uncommon for a websites to use PDF technology. For example, an eCommerce store may offer a "printable receipt" option that, when selected, displays a PDF file within the browser. Last week's article, Filling in PDF Forms with ASP.NET and iTextSharp, looked at how to work with a special kind of PDF document, namely one that has one or more fields defined. A PDF document can contain various types of user interface elements, which are referred to as fields. For instance, there is a text field, a checkbox field, a combobox field, and more. Typically, the person viewing the PDF on her computer interacts with the document's fields; however, it is possible to enumerate and fill a PDF's fields programmatically, as we saw in last week's article. This article continues our investigation into iTextSharp, a .NET open source library for PDF generation, showing how to use iTextSharp to create PDF documents from scratch. We start with an example of how to programmatically define and piece together paragraphs, tables, and images into a single PDF file. Following that, we explore how to use iTextSharp's built-in capabilities to convert HTML into PDF. Read on to learn more! Read More >

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C# Adds Optional and Named Arguments

Earlier this month Microsoft released Visual Studio 2010, the .NET Framework 4.0 (which includes ASP.NET 4.0), and new versions of their core programming languages: C# 4.0 and Visual Basic 10. In designing the latest versions of C# and VB, Microsoft has worked to bring the two languages into closer parity. Certain features available in C# were missing in VB, and vice-a-versa. Last week I wrote about Visual Basic 2010's language enhancements, which include implicit line continuation, auto-implemented properties, and collection initializers - three useful features that were available in previous versions of C#. Similarly, C# 4.0 introduces new features to the C# programming language that were available in earlier versions of Visual Basic, namely optional arguments and named arguments. Optional arguments allow developers to specify default values for one or more arguments to a method. When calling such a method, these optional arguments may be omitted, in which case their default value is used. In a nutshell, optional arguments allow for a more terse syntax for method overloading. Named arguments, on the other hand, improve readability by allowing developers to indicate the name of an argument (along with its value) when calling a method. This article examines how to use optional arguments and named arguments in C# 4.0. Read on to learn more! Read More >

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Advice for Storing and Displaying Dates and Times Across Different Time Zones

A common question I receive from clients, colleagues, and 4Guys readers is for recommendations on how best to store and display dates and times in a data-driven web application. One of the challenges in storing and displaying dates in a web application is that it is quite likely that the visitors arriving at your site are not in the same time zone as your web server; moreover, it's very likely that your site attracts visitors from many different time zones from around the world. Consider an online messageboard site, like ASPMessageboard.com, where each of 1,000,000+ posts includes the date and time it was made. Imagine a user from New York leaves a post on April 7th at 4:30 PM and that the web server hosting the site is located in Dallas, Texas, which is one hour earlier than New York. When storing that post to the database do you record the post's date and time relative to the visitor (4:30 PM), the relative to the web server (3:30 PM), or some other value? And when displaying this post how do you show that date and time to a reader in San Francisco, which is three hours earlier than New York? Do you show the time relative to the person who made the post (4:30 PM), relative to the web server (3:30 PM), or relative to the user (1:30 PM)? And if you decide to store or display the date based on the poster's or visitor's time zone then how do you know their time zone and its offset? How do you account for daylight savings, and so on? This article provides guidance on how to store and display dates and times for visitors across different time zones and includes a demo that gives a working example of some of these techniques. Read on to learn more! Read More >

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Comparing the Performance of Visual Studio's Web Reference to a Custom Class

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. Recently a client made us question one of our fundamental assumptions about the .NET Framework and Web Services by asking, "Why should we use proxy class created by Visual Studio to connect to a web service?" In this particular project we were calling a web service to retrieve data, which was then sorted, formatted slightly and displayed in a web page. The client hypothesized that it would be more efficient to invoke the web service directly via the HttpWebRequest class, retrieve the XML output, populate an XmlDocument object, then use XSLT to output the result to HTML. Surely that would be faster than using Visual Studio's auto-generated proxy class, right? Prior to this request, we had never considered rolling our own proxy class; we had always taken advantage of the proxy classes Visual Studio auto-generated for us. Could these auto-generated proxy classes be inefficient? Would retrieving and parsing the web service's XML directly be more efficient? The only way to know for sure was to test my client's hypothesis. Read More >

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Checking All Checkboxes in a GridView Using jQuery

In May 2006 I wrote two articles that showed how to add a column of checkboxes to a GridView and offer the ability for users to check (or uncheck) all checkboxes in the column with a single click of the mouse. The first article, Checking All CheckBoxes in a GridView, showed how to add "Check All" and "Uncheck All" buttons to the page above the GridView that, when clicked, checked or unchecked all of the checkboxes. The second article, Checking All CheckBoxes in a GridView Using Client-Side Script and a Check All CheckBox, detailed how to add a checkbox to the checkbox column in the grid's header row that would check or uncheck all checkboxes in the column. Both articles showed how to implement such functionality on the client-side, thereby removing the need for a postback. The JavaScript presented in these two previous articles still works, but the techniques used are a bit antiquated and hamfisted given the advances made in JavaScript programming over the past few years. For instance, the script presented in the previous articles uses server-side code in the GridView's DataBound event handler to assign a client-side onclick event handler to each checkbox. While this works, it violates the tenets of unobtrusive JavaScript, which is a design guideline for JavaScript programming that encourages a clean separation of functionality from presentation. (Ideally, event handlers for HTML elements are defined in script.) Also, the quantity of JavaScript used in the two previous articles is quite hefty compared to the amount of code that would be needed using modern JavaScript libraries like jQuery. This article presents updated JavaScript for checking (and unchecking) all checkboxes within a GridView. The two examples from the previous articles - checking/unchecking all checkboxes using a button and checking/unchecking all checkboxes using a checkbox in the header row - are reimplemented here using jQuery and unobtrusive JavaScript techniques. Read on to learn more! Read More >

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Building Interactive User Interfaces with Microsoft ASP.NET AJAX: Refreshing An UpdatePanel With Jav

The ASP.NET AJAX UpdatePanel provides a quick and easy way to implement a snappier, AJAX-based user interface in an ASP.NET WebForm. In a nutshell, UpdatePanels allow page developers to refresh selected parts of the page (instead of refreshing the entire page). Typically, an UpdatePanel contains user interface elements that would normally trigger a full page postback - controls like Buttons or DropDownLists that have their AutoPostBack property set to True. Such controls, when placed inside an UpdatePanel, cause a partial page postback to occur. On a partial page postback only the contents of the UpdatePanel are refreshed, avoiding the "flash" of having the entire page reloaded. (For a more in-depth look at the UpdatePanel control, refer back to the Using the UpdatePanel installment in this article series.) Triggering a partial page postback refreshes the contents within an UpdatePanel, but what if you want to refresh an UpdatePanel's contents via JavaScript? Ideally, the UpdatePanel would have a client-side function named something like Refresh that could be called from script to perform a partial page postback and refresh the UpdatePanel. Unfortunately, no such function exists. Instead, you have to write script that triggers a partial page postback for the UpdatePanel you want to refresh. This article looks at how to accomplish this using just a single line of markup/script and includes a working demo you can download and try out for yourself. Read on to learn more! Read More >

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