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Archive for November, 2009

Starting with JQuery

Posted by Virendra Dugar on November 24, 2009

Introduction

JQuery is a Java script libarary/ Java Script framework that simplifies the interaction process or access process of traversing in HTML document. It provides methods to make animations, add ajax interaction to the page, provides an easy way to apply CSS to any items and provides an easy mechanism for binding and unbinding events. Huge code written using Java script can easily replaced by few lines of code in JQuery.

History of JQuery

Initially it’s was released in January 2006 but the very first stable version of JQuery 1.0 was released in August 2006. This version had support for CSS, events and Ajax. After that many version of JQuery were released but the latest version is JQuery 1.3.2. You can download this from JQuery website.

What can be done using JQuery

1. Allows to access elements in the document

If one need to access the DOM tree without any JavaScript libarary, one has to write many lines of code. JQuery provides a selector mechanism to access any part of DOM.

2. Easily apply CSS

As it’s known that CSS is the most powerful and mostly used for good appreance of any webpage. JQuery provides CSS Selectors which allows to change the CSS classes or individual style for any portion of the document. This can be done even after the page is rendered.

3. Make Animation

For better user experience, animation can do the job for you. JQuery provides many methods to perform animations like show,hide, fade, wipe, start, stop etc. Doing all this with JQuery is fun as No huge lines of code, no complex logic.

4. Ajax Interaction

In today’s world, Ajax is one of the most popular technology used in almost every website for better user experience. Jquery provides support for ajax also which allows to access server side event without refreshing the web page.

5. API to change document’s content

JQuery provides API (Application Program Interface) which allows to change the content of the document. Changing Text, inserting images, ordering of list can be done with few keystrokes with JQuery API. Entire structure of HTML can be rewritten or extended.

6. Event handling

Any technology is a failure if it cannot responsed to the user when any event takes place. Jquerys’s event handling is one the decent feature. It quickly responsed to any event such as user clicking a button.

Demo

To start with JQuery, first download the Jquery from it’s official website (http://JQuery.com). Make sure you download the latest copy of the JQuery.

<script src="Script/jquery.js" type="text/javascript"></script>

I have copied the jquery.js and placed it in script directory of the project. In this demo, I am going to show you how easily you can change the CSS and do animation.

Let’s first take a look at HTML

<h2>
History of JQuery</h2>
<div id="content">
Initially it's was released in January 2006 but the very first stable version of JQuery 1.0 was released in August 2006. This version had support for CSS,events and Ajax. After that many version of JQuery were released but the latest version is JQuery 1.3.2. You can download this from JQuery website.
</div>

As you can see, I have placed a div tag with it’s ID set to content. Now, I will show you how you can find the div and apply CSS to it using JQuery.

<style type="text/css">
    .ApplyColor
        {
            background-color: Gray;
            font-family: Arial;
            font-size: 10pt;
            color: White;
        }
    h2
        {
            font-size: 20pt;
        }
</style>

<script type="text/javascript" language="javascript">

    $(document).ready(function() {
        $('#content').addClass('ApplyColor');
    });
</script>

.ready() is a jQuery event handler. This particular event handler will execute when the document is ready to be accessed and scripts have completed loading. A .ready() handler can be placed anywhere on the page and you can even have multiple ready handlers in the page.

Now, if you run this page, you will see the div with content id is having gray background and white color foreground.

Let’s go to the animation part with JQuery.

Place a button and some text in Paragraph tag. Using JQuery, I will add a click event handler.

<asp:Button ID="btnShow" runat="server" Text="Show" />
<p style="display: none;background-color:Red">
    Hello
</p>

Now add this Jquery code to document.ready event

<script type="text/javascript" language="javascript">

    $(document).ready(function() {
        $('#btnShow').click(function() {
              $("p").show("");
              return false;
        });
    });

</script>

Above code will find the btnshow and add a click event handler to it. When the button is click then Jquery will find the p tag and make a call to show function which will display the content of the p tag on the screen.

Like wise there are many more functions for animation. You can find the whole list over here.

Reference

 

http://jquery.com/

Conclusion

This is just an overview of starting with Jquery. Many more complex things can be done via jquery with ease. Go to this main page of Jquery and learn as much as you can.

Happy Programming…

Virendra Dugar 🙂

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Copy DLL From GAC

Posted by Virendra Dugar on November 16, 2009

Introduction

The idea behind writing this article is to share solution to one problem that I faced recently for one my project. The problem was how we can copy an assembly (.DLL) file from Global Assembly Cache (GAC). Well, if it simply copy and paste then I am wasting my and your valuable time over here. There is no point have an article such as this. When you read the article heading, it looks pretty simple but it is not. Let’s first start with the basics.

The Basics

Assembly: According to MSDN “Assemblies are the building blocks of .NET Framework applications; they form the fundamental unit of deployment, version control, reuse, activation scoping, and security permissions. An assembly is a collection of types and resources that are built to work together and form a logical unit of functionality. An assembly provides the common language runtime with the information it needs to be aware of type implementations.

There are two types of assembly

  • Private: The assembly which is used only by a single application is called as private assembly.It does not require strong name and versioning.
  • Shared: Assembly which can be used across multiple applications is called shared assembly.

Click here to find more details about assembly.

GAC (Global assembly cache):  GAC is a place where .NET assemblies are stored, specifically used to be shared by multiple applications on that computer.

GACUtil is a command line tool which allows you to place, to remove assembly from GAC.

To install an assembly called VirendraAssembly in the GAC, you can use the command.

gacutil /i VirendraAssembly.dll

To uninstall an assembly called VirendraAssembly in the GAC, you can use the command

gacutil /u VirendraAssebmly.dll

I will not go into the details of gacutil you can find from this link.

But have you ever tried to copy DLL from GAC (Global assembly cache)? Well, first time when someone asked me, I said go to GAC (c:\Windows\Assembly) folder, Select the assembly you want to copy, then right click on it and select copy option and paste it at your desired location. Well, I tried the same way but unfortunately there is no option available to copy when you make a right click on any assembly. Only available options are uninstall and properties option.

See the below screen shot.

Options

One more thing that is noticeable is, go to DOS prompt and fire DIR command to see the listing of C:\Windows\Assembly folder and you will be surprised to see the listing. See below screen shot.

Screen2

Where C:\Windows\Assembly folder looks like this.See Screenshot below:

Screen1

Surprised!! Well, what you see on the DOS Prompt is the internal structure of GAC folder then why windows is not showing such structure of the GAC. Well, this is because off SHFusion.dll (Assembly cache Viewer). On the Dos Prompt fire Dir /AH command. It shows desktop.ini. SHFusion.dll uses this desktop.ini file to show abstract view of GAC.

Various Techniques to show internal structure of GAC

There are 4 ways to show the same structure for GAC in windows as we will in DOS.

Rename the Desktop.ini file

As I mentioned previously, SHFusion.dll make use of desktop.ini to determine how to display the content of the GAC folder. From DOS prompt, fire these commands to rename the desktop.ini file.

attrib desktop.ini -h -r -s
rename desktop.ini desktop.ini.bak

Now, go to C:\Windows\Assembly folder to see its content. Screen will look something like below screenshot

Screen3

You can also see the particular folder content. Select GAC and you will see something like this.

Screen4

If you want to see both the view together run this series of commands on DOS Prompt.

Assuming you are on c:\ drive.

cd Windows\Assembly
attrib -r -h -s desktop.ini
mkdir OriginalView
move desktop.ini OriginalView
attrib +s OriginalView
attrib +r +h +s OriginalView/desktop.ini

Now, go to assembly folder. You will internal structure of GAC and plus one more folder named OriginalView. When you go in this folder, you will  see original view of GAC.

By Modifying the Registry

The following steps will modify the registry. If you make any incorrect entry in registry, that can cause some serious problems. Sometimes you may need to install operating system again. Use registry editor at your own risk. I prefer, before you follow these steps, take a backup of registry.

We need to add a key in registry that will disable the abstract view of the GAC.

To open registry editor, Go to Run and type regedit. Locate following registry, in the registry editor.
HKEY_Local_Machine\Software\Microsoft\Fusion\

Registry1

Right click on Fusion Folder and select New ->DWord Value.

Registry 2

Add a new Dword named “DisableCacheViewer” and set its value 1.

Registry 3

Now go to C:\Windows\Assembly folder and you will see folders in GAC.

By Uninstalling SHFusion.dll

Go to Visual Studio Command Prompt and fire this command to uninstall the SHFusion.dll

regsvr32 -u C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\shfusion.dll

Command

Following message will appear.

Message

Now go to C:\Windows\Assembly folder and you will see folders in GAC.

To get back to the previous state of view register the SHfusion.dll using the following command, fire this command on Visual Studio Command prompt.

regsvr32 C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\shfusion.dll

Command

And you will see following message on the screen.

Message

Now go to Assembly folder again and it will show the abstract view of GAC.

Using SUBST Command

Go to Windows DOS Prompt and type following command and press enter.

SUBST L: “C:\Windows\Assembly”

SUBST

This command will create a virtual drive “L” and this drive will have the internal view of GAC, where C:\Windows\Assembly will have the abstract view of GAC. Kindly ensure that the drive name that you type in SUBST command, it must not exist in your system. Go to My Computer and you will see the Drive named “L:”.

Now to delete this drive, run this command on command prompt.

SUBST L: /D

This will delete the L: drive.

By all above these four techniques, you can see the internal structure of GAC. Via Internal structure you can copy the DLL and paste it at desired location.

Now, let’s see what every folder contains in GAC. Mainly there are 5 Folders.

  1. GAC : This folder contains non-native images of DLL used in .NET Framework 1.x.
  2. GAC_32 : A 32-bit system will only have the GAC_32 directory.  A 64-bit system will have both the directory GAC_32 and GAC_64. These directories contain assemblies that are specific to 32-64 bit mode.
  3. GAC_MSIL: The GAC_MSIL cache contains assemblies that can be run in either 32-bit or 64-bit mode. They don’t have any dependency.
  4. NativeImage Framework Version :  Native image generated for Framework version. If you have .NET Framework 1.0 and 2.0 both, then there will be two directories.
  5. Temporary and Tmp : Temporary Directories.

The folder GAC, GAC_32, GAC_64 and GAC_MSIL contains non-native images of the DLLs. They all contain the MSIL that will be complied into native images and placed in NativeImage_Framework Version folder.

Reference

http://www.codeproject.com/KB/dotnet/demystifygac.aspx
http://blogs.msdn.com/junfeng/archive/2004/09/12/228635.aspx

Conclusion

During this article, I have showed you various techniques to show internal structure of GAC and one can easily copy the DLL from the GAC folder and can paste it at desired location. I hope that readers will learn something new.

Kindly post your comments regarding feedback for this article.

Thanks,
Virendra Dugar

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