Sharepoint Feature Upgrades - sharepoint-2010

Question

I have the following in my feature.template.xml
...
<VersionRange BeginVersion="1.0.0.1" EndVersion="1.0.0.2">
<CustomUpgradeAction Name="1.0.0.1_TO_1.0.0.2"></CustomUpgradeAction>
</VersionRange>
<VersionRange BeginVersion="1.0.0.2" EndVersion="1.0.0.3">
<CustomUpgradeAction Name="1.0.0.2_TO_1.0.0.3"></CustomUpgradeAction>
</VersionRange>
...
My feature upgrade event is as follows:
public override void FeatureUpgrading(SPFeatureReceiverProperties properties, string upgradeActionName, System.Collections.Generic.IDictionary<string, string> parameters)
{
using (SPSite site = (SPSite)properties.Feature.Parent)
using (SPWeb mySite = site.RootWeb)
{
switch (upgradeActionName)
{
case "1.0.0.1_TO_1.0.0.2":
//execute logicA
break;
case "1.0.0.2_TO_1.0.0.3":
//execute logicB
break;
default:
break;
}
}
Am I correct in saying that if the site is currently version 1.0.0.0, it will be upgraded to v 1.0.03, executing both logicA and logicB above. This means that sharepoint would call featureupgrading event for each version upgrade.Is this correct? Or do I need to do something different to achieve this?
I also have the following concerns:
What exactly do the the BeginVersion and EndVersion mean.
I especially do not understand the BeginVersion. What happens if instead of 1.0.0.2 I set it to 1.0.0.1 as well?
Any assistance would be greately appreciated, as I did not find any good relevant details online or on books.

Answer 1

When you add a new Feature to your VS SharePoint project, Visual studio initializes your Feature with version 0.0.0.0.
In the properties window you can set a version number for your feature.
When you want to upgrade an existing feature you'll have to define the range of versions for which you want your upgrade actions (code, new manifest, ...) to happen.
E.g.: You deployed your feature without changing the version number. Your current deployed feature has version number 0.0.0.0.
You want to upgrade your feature and set the version number to 2.0.0.0.
If you define a versionrange as follows:
<VersionRange BeginVersion="1.0.0.0" EndVersion="2.0.0.0">
You'll notice nothing will happen when you call SPFeature.Upgrade() since 0.0.0.0 is not in the defined versionrange.
If you use this versionrange
<VersionRange EndVersion="2.0.0.0">
or
<VersionRange BeginVersion="0.0.0.0" EndVersion="2.0.0.0">
You'll notice your FeatureUpgrading eventreceiver or other upgrade actions will be triggered.
Your upgraded feature will now have version number 2.0.0.0.
If you call SPFeature.Upgrade again nothing will happen again, because 2.0.0.0 exceeds the defined versionrange. So BeginVersion is included, EndVersion not.
Every feature with a version number between [0.0.0.0 - 1.x.x.x] will be upgraded if you use the latter versionranges.
I think you can also leave the BeginVersion and EndVersion attributes entirely out. Then you're upgradeactions will be triggered at every SPFeature.Upgrade() call. (To be verified)
For more information: Chris O'Brien wrote an interesting articles series about this topic, cfr. http://www.sharepointnutsandbolts.com/2010/06/feature-upgrade-part-1-fundamentals.html