How to: Get a Service

You often need to get Visual Studio services to access different features. In general, a Visual Studio service provides one or more interfaces that you can use. You can get most services from a VSPackage.

Any VSPackage that derives from Package and that has been correctly sited can ask for any global service. Because the Package class implements IServiceProvider, any VSPackage that derives from Package is also a service provider.

When Visual Studio loads a Package, it passes an IServiceProvider object to the SetSite method during initialization. This is called siting the VSPackage. The Package class wraps this service provider and provides the GetService method for getting services.

Getting a service from an initialized VSPackage

1. Every Visual Studio extension starts with a VSIX deployment project which will contain the extension assets. Create a Visual Studio VSIX project named GetServiceExtension. You can find the VSIX project template in the New Project dialog under Visual C# / Extensibility.

2. Now add a custom command item template named GetServiceCommand. In the Add New Item dialog, go to Visual C# / Extensibility and select Custom Command. In the Name field at the bottom of the window, change the command file name to GetServiceCommand.cs. For more information about how to create a custom command, Creating an Extension with a Menu Command

3. In GetServiceCommand.cs, remove the body of the MenuItemCommand method and add the following code:

   IVsActivityLog activityLog = ServiceProvider.GetService(typeof(SVsActivityLog)) as IVsActivityLog;  
   if (activityLog == null) return;  
   System.Windows.Forms.MessageBox.Show("Found the activity log service.");  
   
   

   This code gets an SVsActivityLog service and casts it to an IVsActivityLog interface, which can be used to write to the activity log. For an example, see How to: Use the Activity Log.

4. Build the project and start debugging. The experimental instance appears.

5. On the Tools menu of the experimental instance, find the Invoke GetServiceCommand button. When you click this button, you should see a message box that says Found the activity log service.

Getting a service from a tool window or control container

Sometimes you may need to get a service from a tool window or control container that has not been sited, or else has been sited with a service provider that does not know about the service you want. For example, you might want to write to the activity log from within a control.

The static GetGlobalService method relies on a cached service provider that is initialized the first time any VSPackage derived from Package is sited.

Because the VSPackage constructor is called before the VSPackage is sited, global services are typically unavailable from within the VSPackage constructor. See How to: Troubleshoot Services for a workaround.

Here’s an example of the way to get a service in a tool window or other non-VSPackage element.

IVsActivityLog log = Package.GetGlobalService(typeof(SVsActivityLog)) as IVsActivityLog;  
if (log == null) return;  

Getting a service from the DTE object

You can also get services from DTEClass object. However, you must get the DTE object as a service from a VSPackage or by calling the static GetGlobalService method.

The DTE object implements IServiceProvider, which you can use to query for a service by using GetService.

Here’s how to get a service from the DTE object.

// Start with the DTE object, for example:   
// using EnvDTE;  
// DTE dte = (DTE)GetService(typeof(DTE));  
  
ServiceProvider sp = new ServiceProvider((Microsoft.VisualStudio.OLE.Interop.IServiceProvider)dte);  
if (sp != null)  
{  
    IVsActivityLog log = sp.GetService(typeof(SVsActivityLog)) as IVsActivityLog;  
    if (log != null)  
    {   
        System.Windows.Forms.MessageBox.Show("Found the activity log service.");  
    }  
}  

See Also

How to: Provide a Service
Using and Providing Services
Service Essentials