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ASP.NET Web Pages - Helpers


Web Helpers greatly simplifies web development and common programming tasks.


ASP.NET Helpers

ASP.NET helpers are components that can be accessed by single lines of Razor code.

You can build your own helpers using Razor syntax stored as .cshtml files, or use built-in ASP.NET helpers.

You will learn how to use Razor helpers in the next chapters of this tutorial.

Below is a short description of some useful Razor helpers:


The WebGrid Helper

The WebGrid helper simplifies the way to display data:

  • Automatically sets up an HTML table to display data
  • Supports different options for formatting
  • Supports paging (First, next, previous, last) through data
  • Supports sorting by clicking on column headings

The Chart Helper

The "Chart Helper" can display chart images of different types with many formatting options and labels.

chart chart

The Chart helper can display data from arrays , from databases, or from files.


The WebMail Helper

The WebMail helper provides functions for sending email messages using SMTP (Simple Mail Transfer Protocol).


The WebImage Helper

The WebImage helper provides functionality to manage images in a web page.

Keywords: flip, rotate, resize, watermark.



Third Party Helpers

With Razor you can take advantage of built-in or third party helpers to simplify the use of email, databases, multimedia, and social networks as well as many other issues like navigation and web security.


Analytics (Google)

Helper Description
Analytics.GetGoogleHtml(webPropertyId) Renders the Google Analytics JavaScript code for the specified ID.
Analytics.GetStatCounterHtml(project, security)Renders the StatCounter Analytics JavaScript code for the specified project.
Analytics.GetYahooHtml(account) Renders the Yahoo Analytics JavaScript code for the specified account.

Bing

Helper Description
Bing.SearchBox([boxWidth]) Passes a search to Bing. To specify the site to search and a title for the search box, you can set the Bing.SiteUrl and Bing.SiteTitle properties. Normally you set these properties in the _AppStart page.
Bing.AdvancedSearchBox([, boxWidth] [, resultWidth] [, resultHeight]
  [, themeColor] [, locale]
)
Displays Bing search results in the page with optional formatting. To specify the site to search and a title for the search box, you can set the Bing.SiteUrl and Bing.SiteTitle properties. Normally you set these properties in the _AppStart page.

Crypto

Helper Description
Crypto.Hash(string [, algorithm])
Crypto.Hash(bytes [, algorithm])
Returns a hash for the specified data. The default algorithm is sha256.

Facebook

Helper Description
Facebook.LikeButton(href [, buttonLayout] [, showFaces] [, width] [, height]
[, action] [, font] [, colorScheme] [, refLabel]
)
Lets Facebook users make a connection to pages.

FileUpload

Helper Description
FileUpload.GetHtml([initialNumberOfFiles] [, allowMoreFilesToBeAdded]
  [
, includeFormTag] [, addText] [, uploadText])
Renders UI for uploading files.

GamerCard

Helper Description
GamerCard.GetHtml(gamerTag) Renders the specified Xbox gamer tag.

Gravatar Object Reference

Helper Description
Gravatar.GetHtml(email [, imageSize] [, defaultImage] [, rating]
  [, imageExtension] [, attributes]
)
Renders the Gravatar image for the specified email address.

Json

Helper Description
Json.Encode(object) Converts a data object to a string in the JavaScript Object Notation (JSON) format.
Json.Decode(string) Converts a JSON-encoded input string to a data object that you can iterate over or insert into a database.

LinkShare

Helper Description
LinkShare.GetHtml(pageTitle [, pageLinkBack] [, twitterUserName]
  [, additionalTweetText] [, linkSites]
)
Renders social networking links using the specified title and optional URL.

ModelState

Helper Description
ModelStateDictionary.AddError(key, errorMessage)Associates an error message with a form field. Use the ModelState helper to access this member.
ModelStateDictionary.AddFormError(errorMessage) Associates an error message with a form. Use the ModelState helper to access this member.
ModelStateDictionary.IsValid Returns true if there are no validation errors. Use the ModelState helper to access this member.

ObjectInfo

Helper Description
ObjectInfo.Print(value [, depth] [, enumerationLength])Renders the properties and values of an object and any child objects.

Recaptcha

Helper Description
Recaptcha.GetHtml([, publicKey] [, theme] [, language] [, tabIndex]) Renders the reCAPTCHA verification test.
ReCaptcha.PublicKey
ReCaptcha.PrivateKey
Sets public and private keys for the reCAPTCHA service. Normally you set these properties in the _AppStart page.
ReCaptcha.Validate([, privateKey]) Returns the result of the reCAPTCHA test.

ServerInfo

Helper Description
ServerInfo.GetHtml()Renders status information about ASP.NET Web Pages.

Twitter

Helper Description
Twitter.Profile(twitterUserName) Renders a Twitter stream for the specified user.
Twitter.Search(searchQuery) Renders a Twitter stream for the specified search text.

Video

Helper Description
Video.Flash(filename [, width, height]) Renders a Flash video player for the specified file with optional width and height.
Video.MediaPlayer(filename [, width, height])Renders a Windows Media player for the specified file with optional width and height.
Video.Silverlight(filename, width, height)Renders a Silverlight player for the specified .xap file with required width and height.

WebCache

Helper Description
WebCache.Get(key) Returns the object specified by key, or null if the object is not found.
WebCache.Remove(key) Removes the object specified by key from the cache.
WebCache.Set(key, value [, minutesToCache] [, slidingExpiration]) Puts value into the cache under the name specified by key.

WebImage

Helper Description
WebImage(path)Loads an image from the specified path.
WebImage.AddImagesWatermark(image) Adds the specified image as a watermark.
WebImage.AddTextWatermark(text) Adds the specified text to the image.
WebImage.FlipHorizontal()
WebImage.FlipVertical()
Flips the image horizontally or vertically.
WebImage.GetImageFromRequest() Loads an image when an image is posted to a page during a file upload.
WebImage.Resize(width, height) Resizes the image.
WebImage.RotateLeft()
WebImage.RotateRight()
Rotates the image to the left or the right.
WebImage.Save(path [, imageFormat]) Saves the image to the specified path.