# Codec_FSharpMapSurrogate<TKey, TValue>.WriteField(Writer<TBufferWriter>, uint, Type, FSharpMapSurrogate<TKey, TValue>)

[Type overview](/orleans/docs/api/csharp/microsoft.orleans.serialization.fsharp/orleanscodegen.orleans.serialization.codec-fsharpmapsurrogate-2/) | [Methods](/orleans/docs/api/csharp/microsoft.orleans.serialization.fsharp/orleanscodegen.orleans.serialization.codec-fsharpmapsurrogate-2/methods/)

```csharp
public void Codec_FSharpMapSurrogate<TKey, WriteField<TBufferWriter>(ref Writer<TBufferWriter> writer, uint fieldIdDelta, Type expectedType, FSharpMapSurrogate<TKey, TValue> value)
```

Writes a field.

### Parameters

- `writer` (`Writer<TBufferWriter>`): The writer.
- `fieldIdDelta` (`uint`): The field identifier delta.
- `expectedType` (`Type`): The expected type.
- `value` (`FSharpMapSurrogate<TKey, TValue>`): The value.