无法将异步 lambda 表达式转换为委托答案

【问题标题】：Cannot convert async lambda expression to delegate无法将异步 lambda 表达式转换为委托
【发布时间】：2018-08-21 07:26:20
【问题描述】：

我正在为 MS Bot 对话框设置单元测试，但出现以下错误，不知道如何解决。任何人都可以帮忙吗？谢谢

错误 CS4010 无法将异步 lambda 表达式转换为委托类型“Task<HttpOperationResponse<BotData>>”。异步 lambda 表达式可能返回 void、Task 或 Task<T>，它们都不能转换为 'Task<HttpOperationResponse<BotData>>'。 D3DirectlineBot.UnitTests C:\Repos\D3DirectlineBot\D3DirectlineBot.UnitTests\MockConnectorFactory.cs 109 活动

模拟类

public Mock<StateClient> MockIBots(MockConnectorFactory mockConnectorFactory)
{
    var botsClient = new Moq.Mock<StateClient>(MockBehavior.Loose);

    botsClient.Setup(d => d.BotState.SetConversationDataWithHttpMessagesAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<BotData>(), It.IsAny<Dictionary<string, List<string>>>(), It.IsAny<CancellationToken>()))
        .Returns<string, string, BotData, Dictionary<string, List<string>>, CancellationToken>(async (channelId, conversationId, data, headers, token) =>
        {
            return await mockConnectorFactory.UpsertData(channelId, null, conversationId, BotStoreType.BotConversationData, data);
        });

        return botsClient;
    }

UpsertData 类

protected async Task<HttpOperationResponse<object>> UpsertData(string channelId, string userId, string conversationId, BotStoreType storeType, BotData data)
{
    var _result = new HttpOperationResponse<object>();
    _result.Request = new HttpRequestMessage();
    try
    {
        var address = AddressFrom(channelId, userId, conversationId);
        await memoryDataStore.SaveAsync(address, storeType, data, CancellationToken.None);
    }
    catch (HttpException e)
    {
        _result.Body = e.Data;
        _result.Response = new HttpResponseMessage { StatusCode = HttpStatusCode.PreconditionFailed };
        return _result;
    }
    catch (Exception)
    {
        _result.Response = new HttpResponseMessage { StatusCode = HttpStatusCode.InternalServerError };
        return _result;
    }
    _result.Body = data;
    _result.Response = new HttpResponseMessage { StatusCode = HttpStatusCode.OK };
    return _result;
}

【问题讨论】：

标签： c# unit-testing moq

【解决方案1】：

你应该直接返回任务而不等待它：

return mockConnectorFactory.UpsertData(channelId, null, conversationId, BotStoreType.BotConversationData, data);

【讨论】：

现在这个错误 CS0029 无法将类型 'System.Threading.Tasks.Task>' 隐式转换为 'Microsoft.Rest.HttpOperationResponse' D3DirectlineBot.UnitTests C:\Repos\D3DirectlineBot\D3DirectlineBot.UnitTests\MockConnectorFactory.cs 104 活动
这个错误错误 CS4010 无法将异步 lambda 表达式转换为委托类型“任务>”。异步 lambda 表达式可能返回 void、Task 或 Task，它们都不能转换为 'Task>'。 D3DirectlineBot.UnitTests C:\Repos\D3DirectlineBot\D3DirectlineBot.UnitTests\MockConnectorFactory.cs 135 活动
您应该在此处删除 async 关键字：CancellationToken>(async (channelId
删除了异步。但是没有两个解决上面提到的错误

【解决方案2】：

UpsertData 类：将HttpOperationResponse<object> 更改为HttpOperationResponse<Botdata>

protected async Task<HttpOperationResponse<Botdata>> UpsertData(string channelId, string userId, string conversationId, BotStoreType storeType, BotData data)
{
    var _result = new HttpOperationResponse<Botdata>();
    _result.Request = new HttpRequestMessage();
    try
    {
        var address = AddressFrom(channelId, userId, conversationId);
        await memoryDataStore.SaveAsync(address, storeType, data, CancellationToken.None);
    }
    catch (HttpException e)
    {
        _result.Body = data;
        _result.Response = new HttpResponseMessage { StatusCode = HttpStatusCode.PreconditionFailed };
        return _result;
    }
    catch (Exception)
    {
        _result.Response = new HttpResponseMessage { StatusCode = HttpStatusCode.InternalServerError };
        return _result;
    }
    _result.Body = data;
    _result.Response = new HttpResponseMessage { StatusCode = HttpStatusCode.OK };
    return _result;
}

MockConnectionFactory 类：删除了@DmitryBogatykh 提到的async 和await

    botsClient.Setup(d => d.BotState.SetConversationDataWithHttpMessagesAsync(It.IsAny<string>(), It.IsAny<string>(), It.IsAny<BotData>(), It.IsAny<Dictionary<string, List<string>>>(), It.IsAny<CancellationToken>()))
        .Returns((string channelId, string conversationId, BotData data, Dictionary<string, List<string>> headers, CancellationToken token) =>
        {
            return  mockConnectorFactory.UpsertData(channelId, null, conversationId, BotStoreType.BotConversationData, data);
        });

【讨论】：