asp.net-mvc-2 – 使用或不使用AutoMapper的“合并”模型和ViewM

So i need a way to merge a ViewModel into a persistence entity. Can I
do that with AutoMapper,or do I have to do it manually?

是的,你可以用AutoMapper做到这一点.例如：

public class Model
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public class ViewModel
{
    public string Name { get; set; }
}

class Program
{
    static void Main()
    {
        // define a map (ideally once per appdomain => usually goes in Application_Start)
        Mapper.CreateMap<ViewModel,Model>();

        // fetch an entity from a db or something
        var model = new Model
        {
            Id = 5,Name = "foo"
        };

        // we get that from the view. It contains only a subset of the
        // entity properties
        var viewModel = new ViewModel
        {
            Name = "bar"
        };

        // Now we merge the view model properties into the model
        Mapper.Map(viewModel,model);

        // at this stage the model.Id stays unchanged because
        // there's no Id property in the view model
        Console.WriteLine(model.Id);

        // and the name has been overwritten
        Console.WriteLine(model.Name);
    }
}

打印：

5
bar

并将其转换为典型的ASP.NET MVC模式：

[HttpPost]
public ActionResult Update(MyViewModel viewModel)
{
    if (!ModelState.IsValid)
    {
        // validation failed => redisplay view 
        return View(viewModel);
    }

    // fetch the domain entity that we want to udpate
    DomainModel model = _repository.Get(viewModel.Id);

    // now merge the properties
    Mapper.Map(viewModel,model);

    // update the domain model
    _repository.Update(mdoel);

    return RedirectToAction("Success");
}