title: Register all viewmodel and services in ViewModelLocator
body: <p>I am developing a new MVVM light Wpf application.I have 25 View and  ViewModels and 25 DataService Interface and its implementations (One implementation for Design time Data service and one for realtime dataservice).</p>
  
  <p>For Eg, Here is a my DataService Interface for my SupplierViewModel:</p>
  
  <pre><code>interface ISupplierDataService
  {
      ObservableCollection&lt;Tbl_Supplier&gt; GetAllSuppliers();
      int GetSupplierCount(string supplierNameMatch);
  }
  </code></pre>
  
  <p>and Here is its implementation for design time :</p>
  
  <pre><code>class SupplierDataServiceMock : ISupplierDataService
  {
  
      public ObservableCollection&lt;Tbl_Supplier&gt; GetAllSuppliers()
      {
        .....
      }
  
      public int GetSupplierCount(string supplierNameMatch)
      {
        ....
      }
  }
  
  class SupplierDataService : ISupplierDataService
  {
  
      public ObservableCollection&lt;Tbl_Supplier&gt; GetAllSuppliers()
      {
        ....
      }
  
      public int GetSupplierCount(string supplierNameMatch)
      {
        ....
      }
  }
  </code></pre>
  
  <p>In ViewModelLocator is I need to register all my 25 ViewModels and its 25 DataService and its implementations like this :</p>
  
  <pre><code> static ViewModelLocator()
      {
          ServiceLocator.SetLocatorProvider(() =&gt; SimpleIoc.Default);
  
          if (ViewModelBase.IsInDesignModeStatic)
          {
              SimpleIoc.Default.Register&lt;ISupplierDataService, SupplierDataServiceMock&gt;();
              SimpleIoc.Default.Register&lt;ICustomerDataService, CustomerDataServiceMock&gt;();
              ....
          }
          else
          {
              SimpleIoc.Default.Register&lt;ISupplierDataService, SupplierDataService&gt;();
              SimpleIoc.Default.Register&lt;ICustomerDataService, CustomerDataService&gt;();
              ....
          }
  
          SimpleIoc.Default.Register&lt;MainViewModel&gt;();
          SimpleIoc.Default.Register&lt;SupplierViewModel&gt;();
          SimpleIoc.Default.Register&lt;CustomerViewModel&gt;();
          ....
      }
  </code></pre>
  
  <p>My question is do I need to register all my 25 ViewModels and its 25 DataService in my ViewModelLocator ?</p>