创建泛型类型的实例

Question

I have the following:

ModelBuilder builder = new ModelBuilder();
builder.Entity<Model>().Add(new ModelMapper());

Instead I would like to use it as follows:

ModelBuilder builder = new ModelBuilder();
builder.Add<ModelMapper>();

So the ModelBuilder Add extension would create a new instance of T and add it to builder.Entity().Add(new T);

How can I do this?

Answer 1

This should do the job using a combination of type constraints. You may want to make this an extension method.

public void Add<TEntity, TMapper>() 
    where TEntity : class
    where TMapper : EntityMapper<TEntity>, new()
{
    this.Entity<TEntity>().Add(new TMapper());
}

And use it like this:

builder.Add<Model, ModelMapper>();