steps for deploying / activating a feature in SharePoint

In order to understand the feature concepts, let's deploy a simple application page, i.e., SimplePageCodeBehind.aspx as feature. So when the user activates this feature, he will be able to browse SimplePageCodeBehind.aspx.
Step 1: Let’s create a project ‘SharePointFeature’. You can find the source code attached with this article. Below is the project tree which has two XML files and a class file which will process the four events: FeatureInstalled, FeaturesUnInstalling, FeatureActivated, and FeatureDeactivating.

Let’s understand these three files first.

• Feature.XML: This is the most important file because it helps SharePoint identify the feature. All features in SharePoint are identified by the GUID key.
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<Feature Id="48DEF2C4-33F9-4885-B0DE-6FE82E9FDCD8"
Title="Go to Custom Pages"
Description="This features enables us to goto Custom Page"
Scope="Web"
Hidden="FALSE"
ImageUrl="menuprofile.gif"
ReceiverAssembly="SharePointFeature, Version=1.0.0.0, Culture=neutral, PublicKeyToken=af83741e324f585c"
ReceiverClass="SharePointFeature.clsFeatureReceiver" 
xmlns="http://schemas.microsoft.com/sharepoint/" >
<ElementManifests>
<ElementManifest Location="ElementManifest.xml" />
</ElementManifests>
</Feature>

To generate a new GUID, click on Tools -> Create GUID and click ‘New GUID’. The Tools menu can be got from within the IDE. We have marked the GUID value which you will need to copy and paste in the feature.xml file.

Other than feature description and title, there are two important things in the XML file. First, it points towards some other XML file, and second, it points to an assembly which captures events.

• ElementManifest.XML file: This file actually specifies how the implementation will look like. There are two important points to be noted for the ElementManiFest.XML file. The custom action tag specifies on which control the feature will be activated. The control we are targeting at this moment is SiteActionsToolBar. This tool bar is the one which you see on the right hand side corner of your SharePoint portal. There is also a URLaction property which specifies which URL it redirects to.
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<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
<CustomAction
Id="SiteActionsToolbar"
GroupId="SiteActions"
Location="Microsoft.SharePoint.StandardMenu"
Sequence="10"
Title="Display Custom Pages"
Description="This links helps to display Custom Page"
ImageUrl="_layouts/SharePoint2/menuprofile.gif">
<UrlAction Url="_layouts/SimplePageCodeBehind.aspx"/>
</CustomAction>
</Elements>

In other words, ElementManifest.xml specifies the location of the feature and which page it should redirect to.

• FeatureReceiver.cs: This class listens and implements custom actions of the feature.
We need to first refer to the SharePoint namespace as shown in the below code snippet.

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using System;
using System.Collections.Generic;
using System.Text;
// Refer the SharePoint namespace
using Microsoft.SharePoint;

We need to implement the SPFeatureReceiver class and implement all the events.

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namespace SharePointFeature
{
    // Inherit from the 'SPFeatureReceiver" class
    public class clsFeatureReceiver : SPFeatureReceiver
    {
        // Implement the four events of SPFeatureReceiver class
        public override void FeatureInstalled(SPFeatureReceiverProperties properties){}
        public override void FeatureUninstalling(SPFeatureReceiverProperties properties) { }
        // This event fires when the feature is activated
        public override void FeatureActivated(SPFeatureReceiverProperties properties)
        {
            ....
            ....
            ....
            ....
        }
        // This event fires when the feature is deactivated
        public override void FeatureDeactivating(SPFeatureReceiverProperties properties) 
        {
        ....
        ....
        ....
        ...
        }
    }
}

As a sample, in the FeatureActivated event, we have set the description and title of the website.

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public override void FeatureActivated(SPFeatureReceiverProperties properties)
{
    // get the object of SharePoint Web
    SPWeb site = (SPWeb)properties.Feature.Parent;
    // Set the description ,properties , titile and update the SpWeb object
    site.Description = "Click on the SiteActions to See how the custom page display";
    site.Properties["OriginalTitle"] = "Display CustomPage";
    site.Properties.Update();
    site.Title = "This Site now has the custom page display";
    site.Update();
}

In FeatureDeactivating, we have reverted back to the title and description.

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public override void FeatureDeactivating(SPFeatureReceiverProperties properties) 
{
    // Get hold of the SharePoint web object and reset back the values
    SPWeb site = (SPWeb)properties.Feature.Parent;
    site.Description = "Custom Page display is disabled";
    site.Title = site.Properties["OriginalTitle"];
    site.Update();
}

• Step 2: We need to register the compiled assembly in GAC and provide the token value in the Feature.XML file. You need to use GACUTIL to register. You can get the token by browsing to ‘c:\Windows\Assembly’ and then viewing the properties of the assembly.


• Step 3: Copy the two XML files, Feature.xml and ElementManisfest.xml in the C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\FEATURES\DisplayCustomPage directory.


• Step 4: Now we need to install the feature using STSADM.exe. So go to the DOS prompt, and go to the ‘C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN’ directory.
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>cd C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN

To install the feature, run the below command using STSADM. Please note that you need to specify the relative directory path and not the physical path of the Feature.xml file.

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>stsadm -o installfeature -filename DisplayCustomPage\Feature.xml

To ensure that SharePoint registers this feature, run IISRESET on the machine.

• Step 5: Now click on Site Action -> Site Settings -> Site Features and Activate the feature.

Now you can see your feature enabled in the site actions menu. If you click on the feature, i.e., ‘Display Custom Pages’, it will redirect you to SimplePageCodeBehind.aspx.

The other point to be noted is that the events have fired and set the title and description as described in the code.

Try to experiment and deactivate the feature and you will see the title and description changing.