# MapFieldCodec<TKey, TValue> Methods

[Type overview](/orleans/docs/api/csharp/microsoft.orleans.serialization.protobuf/orleans.serialization.mapfieldcodec-2/)

## ReadValue(Reader<TInput>, Field) {#readvalue-1-ref-orleans-serialization-buffers-reader-tinput-orleans-serializatio-b2cda751}

[Dedicated page](/orleans/docs/api/csharp/microsoft.orleans.serialization.protobuf/orleans.serialization.mapfieldcodec-2/methods/readvalue-1-ref-orleans-serialization-buffers-reader-tinput-orleans-serializatio-b2cda751/)

[Source](https://github.com/dotnet/orleans/blob/e4e752cedecc2976811db49802c7a999b1f1c704/src/Serializers/Orleans.Serialization.Protobuf/MapFieldCodec.cs#L68-L122)

```csharp
public MapField<TKey, TValue> MapFieldCodec<TKey, ReadValue<TInput>(ref Reader<TInput> reader, Field field)
```

Reads a value.

### Parameters

- `reader` (`Reader<TInput>`): The reader.
- `field` (`Field`): The field.

### Returns

The value.

## WriteField(Writer&lt;TBufferWriter&gt;, uint, Type, MapField&lt;TKey, TValue&gt;) {#writefield-1-ref-orleans-serialization-buffers-writer-tbufferwriter-uint-system-4ee69601}

[Dedicated page](/orleans/docs/api/csharp/microsoft.orleans.serialization.protobuf/orleans.serialization.mapfieldcodec-2/methods/writefield-1-ref-orleans-serialization-buffers-writer-tbufferwriter-uint-system-4ee69601/)

[Source](https://github.com/dotnet/orleans/blob/e4e752cedecc2976811db49802c7a999b1f1c704/src/Serializers/Orleans.Serialization.Protobuf/MapFieldCodec.cs#L43-L63)

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

Writes a field.

### Parameters

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