Solution Lab

Articles, demos and examples that help AppLife users get the most out of their software.

Versioning Options

  • Date:
  • May 13th, 2008
  • Version:


Price List Viewer Example (zip)

Lab Description

Discusses the pros and cons of client side application versioning options, and demonstrates a common versioning technique.

Any application update process must consist of three activities.

  • Checking for an available update
  • Downloading an update
  • Initiating the update process (Applying the update)

With AppLife Update, the Update Controller performs these activities for you. We’ll discuss the first step in the process, determining whether or not an update is available.

To accomplish this, we need a way to identify what version is currently checking for an update. When you first initialize an Update Controller, its Version property is used. The version property follows the {Major}.{Minor}.{Build}.{Revision} format. You can set this property within a form designer or with code.

The Update Controller offers a simple means to synchronize the Update Controller version property with the hosting application assembly version number. This makes sense for many applications as this is a natural key for determining the current application version. To enable this synchronization, simply set the Update Controller UseHostAssemblyVersion property to true.

For many applications though, setting the version property within the designer or using the assembly version for determining the current client version is not the best approach. The primary disadvantage is you actually have to build a new version of the hosting application just to increment the version stamp. For applications with sub-components such as data files or databases that require periodic updating, requiring an application rebuild to publish an update is not the best approach. Another example is an update process that will actually update multiple sub-applications at once. In this scenario as well, a different versioning key would be beneficial.

A common alternate approach with AppLife Update is to use a config file entry to hold the current application version. A registry key or database table could also be used with a similar approach.

Using a config file entry

To use an entry from a config file to version a client, we need to set the Update Controller version property before we check for updates and we need to modify the config file while updating. With AppLife Update, these activities are easily accomplished.

Setting the Client Version

Setting the version on your Update Controller requires one line of code.

//set the version number from the config file

this.updateController.Version = new Version(ConfigurationManager.AppSettings["version"]);

Updating the Client Version

Updating the client version during an update requires adding two actions to the end of your action list update. We’ll use a Set Shared Property action to place the current update version into a property that we can use in a Change Xml Node action. With this action we can easily set the version value within the application config file. With these two actions in place, we can go about publishing updates that perform any updating actions knowing that proper versioning is in place.

To use a registry key or database to maintain the client version value, you would use a Set Registry Value or Transacted Database query action in place of the Change Xml Node action.


By using a config file to maintain the current client application version, your updates do not require building and publishing modified application assemblies. This adds flexibility to your updating process.

Download AppLife Update Here