# NEST 2.4.6: Type Fields - cannot access internal constructor

**URL:** <https://discuss.elastic.co/t/nest-2-4-6-type-fields-cannot-access-internal-constructor/61870>\
**Category:** Elasticsearch\
**Created:** [September 29, 2016, 8:59pm UTC](https://discuss.elastic.co/t/nest-2-4-6-type-fields-cannot-access-internal-constructor/61870 "2016-09-29T20:59:21Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![Denis\_Lamanov](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/denis_lamanov/32/13111_2.png) [@Denis\_Lamanov](https://discuss.elastic.co/u/Denis_Lamanov)\
**Post date:** [September 29, 2016, 8:59pm UTC](https://discuss.elastic.co/t/nest-2-4-6-type-fields-cannot-access-internal-constructor/61870/1 "2016-09-29T20:59:21Z")

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Hi guys, Hi @forloop

How should we initialize Fields in SourceFilter?

Using the latest version of NEST we can't specify source fields since can't use type Fields:

var source = new SourceFilter  
{  
Include = new Fields( new List{ new Field { Name = "test"}})  
}

But cannot access internal constructor of Fields

Thanks

---

<div class="post-metadata">

**Author:** ![forloop](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/forloop/32/9021_2.png) [@forloop](https://discuss.elastic.co/u/forloop)\
**Post date:** [November 24, 2016, 8:59am UTC](https://discuss.elastic.co/t/nest-2-4-6-type-fields-cannot-access-internal-constructor/61870/2 "2016-11-24T08:59:07Z")

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Hey @Denis_Lamanov, for some reason I missed this post first time round 😄

You can construct a `Fields` in NEST 2.x in numerous ways

from `string`

```auto
Fields fieldsFromStrings = new[]
{
    "title",
    "body",
}

```

from expressions, using `Infer.Field`

```auto
Fields fieldsFromExpressions = new[]
{
    Infer.Field<Question>(f => f.Title),
    Infer.Field<Question>(f => f.Body),
}

```

from a mix of the two

```auto
Fields fieldsFromStringsAndExpressions = new[]
{
    Infer.Field<Question>(f => f.Title),
    "body"
}

```

You can also specify boosts as well, as part of the string if using a string, or as the second parameter to field creation methods

```auto
Fields fieldsFromChainedField = 
    Infer.Field<Question>(f => f.Title).And<Question>(f => f.Body);
    

Fields fieldsFromStringsWithBoost = new[]
{
    "title^2",
    Field.Create("body", 5),
}

Fields fieldsFromExpressionsWithBoost = new[]
{
    Infer.Field<Question>(f => f.Title, 2),
    Infer.Field<Question>(f => f.Body, 5),
}

Fields fieldsFromChainedFieldWihtBoost =
    Infer.Field<Question>(f => f.Title, 2).And<Question>(f => f.Body);

```

---

<div class="post-metadata">

**Author:** ![Denis\_Lamanov](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/denis_lamanov/32/13111_2.png) [@Denis\_Lamanov](https://discuss.elastic.co/u/Denis_Lamanov)\
**Post date:** [November 24, 2016, 9:01am UTC](https://discuss.elastic.co/t/nest-2-4-6-type-fields-cannot-access-internal-constructor/61870/3 "2016-11-24T09:01:49Z")

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Hi Russ,

Thanks for the response

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [July 5, 2017, 10:05pm UTC](https://discuss.elastic.co/t/nest-2-4-6-type-fields-cannot-access-internal-constructor/61870/4 "2017-07-05T22:05:28Z")

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