public sealed class CodedValueDomainToken : Token 

{
  // Must be called within QueuedTask.Run
  void CreateCodedDomainSnippet(Geodatabase geodatabase)
  {
    // Create a CodedValueDomain description for water pipes
    CodedValueDomainDescription codedValueDomainDescription = new CodedValueDomainDescription("WaterPipeTypes",
      FieldType.String, new SortedList<object, string> { { "C_1", "Copper" }, { "S_2", "Steel" } })
    {
      SplitPolicy = SplitPolicy.Duplicate,
      MergePolicy = MergePolicy.DefaultValue
    };

    SchemaBuilder schemaBuilder = new SchemaBuilder(geodatabase);

    // Create a coded value domain 
    CodedValueDomainToken codedValueDomainToken = schemaBuilder.Create(codedValueDomainDescription);
    schemaBuilder.Build();
  }
}

{
  // Must be called within QueuedTask.Run
  void AddFieldWithDomainSnippet(Geodatabase geodatabase)
  {
    //The FeatureClass to add field
    string featureClassName = "Pipes";

    SchemaBuilder schemaBuilder = new SchemaBuilder(geodatabase);

    // Create a CodedValueDomain description for water pipes
    CodedValueDomainDescription pipeDomainDescription = new CodedValueDomainDescription("WaterPipeTypes",
      FieldType.String, new SortedList<object, string>
      {
          { "C_1", "Copper" },
          { "S_2", "Steel" }
      })
    {
      SplitPolicy = SplitPolicy.Duplicate,
      MergePolicy = MergePolicy.DefaultValue
    };

    // Create a coded value domain token
    CodedValueDomainToken codedValueDomainToken = schemaBuilder.Create(pipeDomainDescription);

    // Create a new description from domain token
    CodedValueDomainDescription codedValueDomainDescription = new CodedValueDomainDescription(codedValueDomainToken);

    // Create a field named as 'PipeType' using a domain description
    FieldDescription domainFieldDescription = new FieldDescription("PipeType", FieldType.String);
    domainFieldDescription.SetDomainDescription(codedValueDomainDescription);

    //Retrieve existing information for 'Pipes' FeatureClass
    FeatureClassDefinition originalFeatureClassDefinition = geodatabase.GetDefinition<FeatureClassDefinition>(featureClassName);
    FeatureClassDescription originalFeatureClassDescription =
      new FeatureClassDescription(originalFeatureClassDefinition);

    // Add domain field on existing fields
    // Adding a field,'PipeType', which uses the coded value domain to the 'Pipes' FeatureClass
    List<FieldDescription> modifiedFieldDescriptions = new List<FieldDescription>(originalFeatureClassDescription.FieldDescriptions)
      { domainFieldDescription };

    // Create a new description with updated fields for 'Pipes' FeatureClass 
    FeatureClassDescription featureClassDescription = new FeatureClassDescription(originalFeatureClassDescription.Name, modifiedFieldDescriptions,
      originalFeatureClassDescription.ShapeDescription);

    // Update the 'Pipes' FeatureClass with domain field
    schemaBuilder.Modify(featureClassDescription);

    // Build status
    bool buildStatus = schemaBuilder.Build();

    // Build errors
    if (!buildStatus)
    {
      IReadOnlyList<string> errors = schemaBuilder.ErrorMessages;
    }
  }
}