Tech blog

Sometimes a developer needs to render a View as string. Practical scenario would be to create an obvious View and send it via e-mail instead displaying it in browser. Here is a simple way to extract content from a rendered View:

Implement RenderViewToString method

public class HomeController : Controller
{
  protected string RenderViewToString(string viewName, object model)
  {
    string result = null;
    var view = ViewEngines.Engines.FindView(this.ControllerContext, viewName, null).View;
    if (view != null)
    {
      var sb = new StringBuilder();
      using (var writer = new StringWriter(sb))
      {
        var viewContext = new ViewContext(this.ControllerContext, view,
              new ViewDataDictionary(model), new TempDataDictionary(), writer);
        view.Render(viewContext, writer);
        writer.Flush();
      }
      result = sb.ToString();
    }
    return result;
  }
}

Call it in your action method

//Somewhere in HomeController...
public ActionResult Index()
{
    //Render a View named 'Email' to string variable named 'content'
    //Second parameter (model) can be null
    string content = RenderViewToString("Email", new EmailModel());

    //Do something with the content, e.g. send it to e-mail

    //This does nothing to do with rendered string
    return View();
}

Note! This blog post is just an idea than well tested solution, more a review that detailed description.
In Silverlight UserControl and Page classes are usually used with xaml. Root tags in xaml define the type, like so:

xaml
<UserControl x:Class="MyView">
...
</UserControl>

code-behind
namespace MyNamespace
{
  class MyView : UserControl
}

Sometimes, developers want to extend UserControl, i.e. as View by MVVM pattern.

xaml
<v:ViewBase x:Class="MyNamespace.MyView" xmlns:v="clr-namespace:MyNamespace">
...
</v:ViewBase>

code-behind
namespace MyNamespace
{
  class MyView : ViewBase /* ViewBase is a custom class */
}

Step further, every View should have it’s specialized model (ViewModel), thus base class could integrate a Model property. To avoid casting one should use generics, like ViewBase<MyViewModel>.

xaml
<!-- There's a problem, generics cannot be written in xaml. -->

code-behind
namespace MyNamespace
{
  class MyView : ViewBase<MyViewModel> /* ViewBase is a custom class */
}

Generics cannot be written directly in xaml? There is a workaround:
1. Use a wrapper, described here
2. Create a new non-generic class, like in this sample:

xaml
<v:MyViewBase x:Class="MyNamespace.MyView" xmlns:v="clr-namespace:MyNamespace">
...
</v:MyViewBase>

code-behind
namespace MyNamespace
{
  class MyView : MyViewBase
}

public abstract class MyViewBase : ViewBase<MyViewModel>
{
  /* non-generic class */
}

Appendix: ViewBase<TViewModel> class

public abstract class ViewBase<TViewModel> : UserControl, INotifyPropertyChanged where TViewModel : ViewModelBase, new()
{
	private TViewModel model;
	public TViewModel Model
	{
		get
		{
			if (this.model == null)
			{
				this.model = new TViewModel();
				base.DataContext = this.model;
			}
			return this.model;
		}
		set
		{
			if (this.model != value)
			{
				this.model = value;
				base.DataContext = this.model;
				OnPropertyChanged("Model");
			}
		}
	}
}

References:

• StackOverflow: UserControl that has a generic class in its inheritance tree
• StackOverflow: How to correctly inherit from a UserControl defined in xaml in Silverlight