public static IQueryable <T> Wrap <T>(this IQueryable <T> queryable, WrapperContext context)
{
if (queryable == null)
{
throw new ArgumentNullException(nameof(queryable));
}
var visitor = new WrapperVisitor(context);
return(queryable.Provider.CreateQuery <T>(visitor.Visit(queryable.Expression)));
}
public static IQueryable <M> Unwrap <T, M>(this IQueryable <T> queryable, WrapperContext context = null)
where M : T
{
if (queryable == null)
{
throw new ArgumentNullException(nameof(queryable));
}
WrappedQueryable <T, M> wrapped = queryable as WrappedQueryable <T, M>;
if (wrapped == null)
{
throw new NotSupportedException("不支持的类型。");
}
WrappedQueryableProvider <T, M> provider = wrapped.Provider;
var visitor = new WrapperVisitor(context ?? provider.Context);
var expression = visitor.Visit(wrapped.Expression);
return(provider.InnerQueryProvider.CreateQuery <M>(expression));
}
IEnumerator IEnumerable.GetEnumerator()
{
WrapperVisitor visitor = new WrapperVisitor(Provider.Context);
return(new WrappedEnumerator <T, M>(Provider.InnerQueryProvider.CreateQuery <M>(visitor.Visit(Expression)).GetEnumerator()));
}
public TResult Execute <TResult>(Expression expression)
{
WrapperVisitor visitor = new WrapperVisitor(Context);
return(InnerQueryProvider.Execute <TResult>(visitor.Visit(expression)));
}
public object Execute(Expression expression)
{
WrapperVisitor visitor = new WrapperVisitor(Context);
return(InnerQueryProvider.Execute(visitor.Visit(expression)));
}