Graph API读取日历事件Expand Extensions时JSON解析错误求助

我用C#和Graph API为委派用户创建、读取日历事件，不使用Open Extensions时一切正常。创建带OpenTypeExtension的日历事件代码可成功执行，但读取时取消注释requestConfiguration.QueryParameters.Expand = new string[] { "extensions" };后，无法读取任何事件，抛出JSON解析错误。

创建带OpenTypeExtension的事件代码 #

var precomExtension = new OpenTypeExtension
{
    OdataType = "microsoft.graph.openTypeExtension",
    ExtensionName = "com.zxcasd.zxcasdExtensions",
    AdditionalData = new Dictionary<string, object>
    {
        {
            "zxcasd" , "1234586"
        }
    }
};

var @event = new Event
{
    Subject = "Kalle Anka",
    Body = new ItemBody
    {
        ContentType = BodyType.Text,
        Content = "This is a test from zxczxc, sorry for any inconvinience it may cause"
    },
    Start = new DateTimeTimeZone
    {
        DateTime = "2025-12-24T14:00:00",
        TimeZone = "Pacific Standard Time"
    },
    End = new DateTimeTimeZone
    {
        DateTime = "2025-12-24T15:00:00",
        TimeZone = "Pacific Standard Time"
    },
    Location = new Location
    {
        DisplayName = "Conference Room"
    },
    Extensions = new List<Extension>
    {
        precomExtension
    },
};

try
{
    await graphClient.Users[userEmail].Events.PostAsync(@event);
    Console.WriteLine("Event created successfully!");
}
catch (ServiceException ex)
{
    Console.WriteLine($"Error creating event: {ex.Message}");
}

读取事件代码（取消注释Expand后报错） #

var events3 = await graphServiceClient
    .Users[user]
    .Events
    .GetAsync(requestConfiguration =>
    {
        requestConfiguration.QueryParameters.Select = new string[] { "Id", "Subject", "Start", "End", "Organizer", "createdDateTime", "lastModifiedDateTime" };
        requestConfiguration.QueryParameters.Expand = new string[] { "extensions" };
        requestConfiguration.QueryParameters.Filter = $"start/dateTime ge '{startDateString}' and end/dateTime le '{endDateString}'";
        requestConfiguration.QueryParameters.Orderby = new string[] { $"start/dateTime" };
        requestConfiguration.QueryParameters.Top = 9999;
    });

if (events3?.Value?.Count() > 0)
{
    Console.WriteLine($"Nr of retrived events: {events3.Value.Count}");
    Console.WriteLine("*********************************");
}
foreach (var eventItem in events3.Value)
{
    Console.WriteLine($"Id: {eventItem.Id}");
    Console.WriteLine($"Start: {eventItem.Start.DateTime}");
    Console.WriteLine($"End: {eventItem.End.DateTime}");
    Console.WriteLine($"Subject: {eventItem.Subject}");
    Console.WriteLine($"Organizer: {eventItem.Organizer?.EmailAddress?.Name ?? "No organizer"}");
    Console.WriteLine($"Created: {eventItem.CreatedDateTime}");
    Console.WriteLine($"LastModified: {eventItem.LastModifiedDateTime}");
    Console.WriteLine("*********************************");
}

抛出的错误信息 #

{"Expected depth to be zero at the end of the JSON payload. There is an open JSON object or array that should be closed. LineNumber: 0 | BytePositionInLine: 437."}
    BytePositionInLine: 437
    Data: {System.Collections.ListDictionaryInternal}
    HResult: -2146233088
    HelpLink: null
    InnerException: null
    LineNumber: 0
    Message: "Expected depth to be zero at the end of the JSON payload. There is an open JSON object or array that should be closed. LineNumber: 0 | BytePositionInLine: 437."
    Path: null
    Source: "System.Text.Json"
    StackTrace: "   at System.Text.Json.Utf8JsonReader.ReadSingleSegment()\r\n   at System.Text.Json.Utf8JsonReader.Read()\r\n   at System.Text.Json.JsonDocument.Parse(ReadOnlySpan`1 utf8JsonSpan, JsonReaderOptions readerOptions, MetadataDb& database, StackRowStack& stack)\r\n   at System.Text.Json.JsonDocument.Parse(ReadOnlyMemory`1 utf8Json, JsonReaderOptions readerOptions, Byte[] extraRentedArrayPoolBytes, PooledByteBufferWriter extraPooledByteBufferWriter)\r\n   at System.Text.Json.JsonDocument.<ParseAsyncCore>d__65.MoveNext()\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at Microsoft.Kiota.Serialization.Json.JsonParseNodeFactory.<GetRootParseNodeAsync>d__7.MoveNext()\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at Microsoft.Kiota.Abstractions.Serialization.ParseNodeProxyFactory.<GetRootParseNodeAsync>d__8.MoveNext()\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at Microsoft.Kiota.Abstractions.Serialization.ParseNodeFactoryRegistry.<GetRootParseNodeAsync>d__9.MoveNext()\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at Microsoft.Kiota.Abstractions.Serialization.ParseNodeProxyFactory.<GetRootParseNodeAsync>d__8.MoveNext()\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at Microsoft.Kiota.Http.HttpClientLibrary.HttpClientRequestAdapter.<GetRootParseNodeAsync>d__30.MoveNext()\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at Microsoft.Kiota.Http.HttpClientLibrary.HttpClientRequestAdapter.<SendAsync>d__20`1.MoveNext()\r\n   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()\r\n   at Microsoft.Kiota.Http.HttpClientLibrary.HttpClientRequestAdapter.<SendAsync>d__20`1.MoveNext()\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at Microsoft.Graph.Users.Item.Events.EventsRequestBuilder.<GetAsync>d__8.MoveNext()\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()\r\n   at AzureCalendar.Program.<GetCalendarAppointments>d__5.MoveNext() in E:\_Code_\Testing\AzureCalendar\AzureCalendar\Program.cs:line 229"
    TargetSite: {Boolean ReadSingleSegment()}

问题原因 #

这个错误的核心是批量扩展所有extensions时，Graph API返回的扩展类型混合（包含系统扩展和自定义扩展），导致Kiota序列化器无法正确解析JSON结构。另外，部分事件没有扩展时，返回的extensions字段为null或空数组，和带有扩展的事件返回结构不一致，进一步加剧了解析冲突。

解决方案 #

1. 过滤扩展，只获取自定义的OpenTypeExtension #

不要直接扩展所有extensions，而是通过$filter指定自定义扩展的ID，这样只会返回目标扩展，避免系统扩展干扰：

requestConfiguration.QueryParameters.Expand = new string[] { "extensions($filter=id eq 'com.zxcasd.zxcasdExtensions')" };

2. 单独获取每个事件的扩展 #

先读取所有事件，再针对每个事件单独请求扩展，规避批量解析的类型冲突：

foreach (var eventItem in events3.Value)
{
    Console.WriteLine($"Id: {eventItem.Id}");
    Console.WriteLine($"Start: {eventItem.Start.DateTime}");
    // 其他属性输出...

    // 单独获取当前事件的扩展
    var extensions = await graphServiceClient.Users[user].Events[eventItem.Id].Extensions.GetAsync();
    if (extensions?.Value?.Count > 0)
    {
        var customExt = extensions.Value.FirstOrDefault(e => e.Id == "com.zxcasd.zxcasdExtensions") as OpenTypeExtension;
        if (customExt != null)
        {
            Console.WriteLine($"Custom zxcasd value: {customExt.AdditionalData["zxcasd"]}");
        }
    }
    Console.WriteLine("*********************************");
}

3. 升级Graph SDK版本 #

如果使用的是较旧的Graph SDK v5版本，可能存在Kiota序列化器的bug，升级到最新稳定版可以解决部分解析异常问题。

内容的提问来源于stack exchange，提问作者merger