Sunday, September 20, 2009

Force Validation Using ASP.NET Validation Controls

ASP.NET comes in with a set of validation controls that automatically validate the data entered by a user. Though this validation controls are very powerful and easy to use, they have a small draw back in the sense that they require the entire page to be valid before it's submitted back to the server. There is no direct way to validate only a particular section of the page. This article will explain some circumstances where validating a particular section of page will be required and how to accomplish it.
While validation controls is a great tool for validating user input before data is being submitted there are some situations where we might either want the data to be submitted without validation or we want to validate only particular fields in the form.
A typical example for when we may want the data to be passed through without validation is when a page has both submit and cancels server buttons. When the user clicks the submit button the data has to be validated whereas when the user clicks the cancel post back has to happen without any validation.

The solution for by passing validation on server button click is fairly easy. All we have to do is set the CausesValidation property of the button control to false. Once the CausesValidation property is set to false no validation will happen both on the client side and server side.
The syntax for doing it in the design time is
<asp:button id="cmdCancel" runat="server" Text="Cancel" CausesValidation="False"></asp:button>
This can also be done in runtime using the following code
cmdCancel.CausesValidation = false;

To disable a particular validation control we can use the ValidatorEnable function as shown in the script below
<script language="javascript">
ValidatorEnable(nameofvlaidationcontrol, false)
To disable all the validation control we need to loop through Page_Validators array and disable each validator as shown in script below
<script language="javascript">
for(i=0;i< Page_Validators.length;i++)
{    ValidatorEnable(Page_Validators[i], false);
In order to enable validation only for particular set of controls when a submit button is clicked we need to combine the above two scripts and call it from the client click event of the button as shown in sample below
<script language="javascript">
function enableValidators()
  for(i=0;i< Page_Validators.length;i++)

    ValidatorEnable(Page_Validators[i], false)
  ValidatorEnable(rvState, true);
Attaching the function to the client click event of a submit button
When the cmdSave submit button is clicked all the other validators will be disabled and only the validator named rvState will be enabled. If the validation of rvState is successful then the page will be submitted. The code we have used so far will disable the validatiors only on the client side, so the validation will still happen on the server side and error messages will be shown. To disable particular validators on the server side the following code has to be added to the button click event

Tuesday, September 15, 2009

IE 8: Developer Tools

We definitely start loving IE 8 a lot more than we expected and as we discover newer features in it.

IE 8 includes a add-in called Developer Tools, which will allow you to analyze websites much more better than earlier versions of the browser.

These developer tools can be accessed by going to Tools –> Developer Tools or simply pressing F12 key.

Here are few built in developer tools that are available,

  • Debugging of HTML & CSS
  • Code Search
  • Source viewing
  • Outline elements on screen
  • Controlling caching and cookies
  • Browser Modes.

More information watch this webcast

File Monitoring in .NET

File monitoring applications can be easily developed in .NET using the FileSystemWatcher class. This class listens to changes in files system and raises events whenever changes happen. This article explains how to monitor changes in files and subdirectories of a directory using the FileSystemWatcher class.
The FileSystemWatcher is available within the System.IO namespace. We need to include the System.IO namespace for accessing the FileSystemWatcher class. In order to specify the folder to monitor we have to set the Path property of the FileSystemWatcher as shown below:

FileSystemWatcher fsw = new FileSystemWatcher();
fsw.Path = "c:\\fileWatcher";
If you want to monitor changes to a specific file then the Filter property should be used along with the Path property. The Filter property should be set to file name and the Path property should be set to the path of the folder as shown below
fsw.Path = "c:\\fileWatcher ";
fsw.Filter = "TestWatchFile.txt";
Wild card characters can also be used to specify set of files as shown below
fsw.Filter = "*.txt";
The FileSystemWatcher to begin monitoring we have to set the EnableRaisingEvents property to true
fsw.EnableRaisingEvents = true;

As mentioned before the FileSystemWatcher raises events whenever changes like creation, deletion etc happens to the specific folder or file. The events that are raised by FileSystemWatcher are Changed, Created, Deleted, Error and Renamed.

We need to write appropriate event handlers to handle these events. The FileSystemEventHandler has an argument named FileSystemEventArgs, which provides useful event data. The data provided by the FileSystemEventArgs are ChangeType which gives the type of change that occurred and Path which gives the full path of the affected file or folder.

A sample Changed event handler is given below
fsw.Changed += new FileSystemEventHandler(fsw_changed);
fsw.Deleted += new FileSystemEventHandler(fsw_changed);
fsw.Created += new FileSystemEventHandler(fsw_changed);
private void fsw_changed(object Sender,FileSystemEventArgs e)
MessageBox.Show("The file" + e.FullPath+ " was " + e.ChangeType.ToString() + " on " + System.DateTime.Now.ToString());

FileSystemObject class can be used to monitor files or folders by setting appropriate properties and handling the events raised by the class.

Monday, September 14, 2009

Executing ASP Page in ASP.NET

When migrating applications from ASP to ASP.NET there may be situations where you would like to use some of the existing ASP code within ASP.NET pages. This how can we achieve to do so.

We can embed ASP pages within ASP.Net pages by suing screen-scraping mechanisms provided by the WebRequest and WebResponse classes, which are within the System.Net namespace. These two classes provide a request/response model for accessing data from Internet. Using the WebRequest class we can create a request to the asp page, which you need to embed within ASP.NET page. The WebResponse class is used to receive the response generated by the request. We then use the StreamReader class to get the contents of the response and display it on the screen.
All this functionality is encapsulated within a static method of a class as given in the code below. This static function accepts the name of the ASP page to be embedded. It gets response from the ASP page and returns the response content as a string.
public class ASPWithInASPNet
public static void GetASPResults(string AspPage)
Regex objRegex = new Regex(@"^http\://[a-zA-Z0-9\-\.]+[a-zA-Z]{2,3}(/\S*)?$");
string StrPath;
StrPath = AspPage;
Uri RequestURI = HttpContext.Current.Request.Url;
StrPath = RequestURI.Scheme+ "://" + RequestURI.Host +
HttpContext.Current.Request.ApplicationPath + "/";
StrPath = StrPath + AspPage;
HttpWebRequest WebReq =
WebResponse WebRes = WebReq.GetResponse();
StreamReader SR = new StreamReader(WebRes.GetResponseStream());
catch(WebException Ex)
HttpContext.Current.Response.Write( Ex.Message);
This class can be used in any of you ASP.Net pages as shown in the sample below.
private void Page_Load(object sender, System.EventArgs e)
Note: This functionality can be used to embed not only ASP pages but also any web page like JSP, HTML etc.

Friday, September 04, 2009

Build the Newest Silverlight 3 Applications with Expression

Silverlight 3 and Expression Studio 3 help you create and deploy Web sites and rich Internet applications more easily than ever. Download Silverlight 3 and the Expression Studio 3 60-day trial today.

View article...

Wednesday, September 02, 2009


HTML 5 is the next major revision of HTML (Hypertext Markup Language), the core markup language of the World Wide Web.

HTML 5 is the proposed next standard for both HTML 4.01 and XHTML 1.0, as development on the next version of the latter has stopped. HTML 5 was initially said to become a game-changer in Web application development, making obsolete such plug-in-based rich Internet application (RIA) technologies as Adobe Flash, Microsoft Silverlight, and Sun JavaFX. Such applications would be made obsolete by specifying a standard video codec for all browsers to use. However, in December 2007, the editor of the burgeoning draft specification dropped the recommendation of the free software Theora and Vorbis codecs, after opposition from Apple and Nokia. This means HTML 5 does not currently specify a common video codec for Web development.

The ideas behind HTML 5, originally referred to as Web Applications 1.0, were pioneered in 2004 by the Web Hypertext Application Technology Working Group (WHATWG); HTML 5 incorporates Web Forms 2.0, another WHATWG specification. The HTML 5 specification was adopted as the starting point of the work of the new HTML working group of the W3C in 2007.

Difference between HTML4 and HTML5

Click Here for more.