反序列化 Json 失败

Question

我有以下测试但不起作用，

    [Test]
    public async Task Get_Portfolio_ReturnsValuesCorrectly()
    {
        var testServer = TestHelpers.CreateTestServer();
        var client = testServer.CreateClient();
        var portfolio= new Portfolio
        {
            PortfolioId = this.portfolio.Id,
            YearCurve = "Test",
            InflationCurve = "Test",
            PortfolioName = this.portfolio.Name
        };

        await client.PutAsJsonAsync("api/Portfolios/", this.portfolio).ConfigureAwait(false);

        var route = "api/Portfolio/" + portfolio.PortfolioId;

        using (var response = await client.GetAsync(route).ConfigureAwait(false))
        ////using (var stream = await client.GetStreamAsync(route).ConfigureAwait(false))
        {
            var retrievedString= await response.Content.ReadAsStringAsync();

            Portfolio retrievedPortfolio = JsonConvert.DeserializeObject<Portfolio>(retrievedString);

            ////var retrievedCurveType = Serializer.Deserialize<Portfolio>(stream);

            Assert.That(retrievedPortfolio.Id, Is.EqualTo(this.portfolio.Id));
            Assert.That(retrievedPortfolio.PortfolioName, Is.EqualTo(this.portfolio.Name));

        }
    }

测试在所有值中返回空值 json 看起来像那样

"{\"ItemsToSerialize\":{\"PortfolioId\":\"TEST PORTFOLIO_20150131\",\"Id\":\"TEST PORTFOLIO_20150131\",\"YearCurve\":\"Test\",\"InflationCurve\":\"Test\",\"PortfolioName\":\"TEST PORTFOLIO\"}}"

无论我尝试检索为流还是字符串，都失败了

提前致谢