如何在Microsoft.Bot.Builder中为Teams机器人实现两级下拉选择

可行，你可以通过在OnTeamsMessagingExtensionSelectItemAsync中返回新的下拉选项列表而非直接生成卡片，来实现二级下拉选择的需求。核心思路是通过自定义数据标识选中项的层级，在选择事件中动态返回对应层级的选项或最终卡片。

实现步骤 #

1. 定义层级标识类
   创建一个自定义类来存储选项的层级信息和业务数据，用于区分当前处理的是哪一级选择：

   public class SelectionItem
   {
       public string Type { get; set; } // 标识层级："Level1" 或 "Level2"
       public string Id { get; set; } // 选项ID
       public string Name { get; set; } // 选项显示名称
   }
   

2. 返回第一级下拉选项
   在OnTeamsMessagingExtensionQueryAsync中生成第一级选项，将其封装为HeroCard附件并返回：

   protected override async Task<MessagingExtensionResponse> OnTeamsMessagingExtensionQueryAsync(ITurnContext<IInvokeActivity> turnContext, MessagingExtensionQuery query, CancellationToken cancellationToken)
   {
       var level1Items = new List<SelectionItem>
       {
           new SelectionItem { Type = "Level1", Id = "1", Name = "分类A" },
           new SelectionItem { Type = "Level1", Id = "2", Name = "分类B" }
       };
   
       var attachments = level1Items.Select(item => new HeroCard
       {
           Title = item.Name,
           Content = item // 存储自定义数据，供后续选择事件使用
       }.ToAttachment()).ToList();
   
       return new MessagingExtensionResponse
       {
           ComposeExtension = new MessagingExtensionResult
           {
               AttachmentLayout = AttachmentLayoutTypes.List,
               Type = "result",
               Attachments = attachments
           }
       };
   }
   

3. 处理选择事件，动态返回下一级选项或最终卡片
   在OnTeamsMessagingExtensionSelectItemAsync中，根据选中项的层级标识，决定返回第二级下拉选项还是最终卡片：

   protected override async Task<MessagingExtensionResponse> OnTeamsMessagingExtensionSelectItemAsync(ITurnContext<IInvokeActivity> turnContext, JObject query, CancellationToken cancellationToken)
   {
       var selectedItem = query.ToObject<SelectionItem>();
   
       if (selectedItem.Type == "Level1")
       {
           // 根据第一级选项ID生成第二级选项
           var level2Items = GetLevel2Options(selectedItem.Id);
   
           var attachments = level2Items.Select(item => new HeroCard
           {
               Title = item.Name,
               Content = item
           }.ToAttachment()).ToList();
   
           return new MessagingExtensionResponse
           {
               ComposeExtension = new MessagingExtensionResult
               {
                   AttachmentLayout = AttachmentLayoutTypes.List,
                   Type = "result",
                   Attachments = attachments
               }
           };
       }
       else if (selectedItem.Type == "Level2")
       {
           // 生成最终展示的自适应卡片
           var finalCard = new AdaptiveCard(new AdaptiveSchemaVersion(1.0))
           {
               Body = { new AdaptiveTextBlock { Text = $"已选择：{selectedItem.Name}", Size = AdaptiveTextSize.Large } }
           };
   
           return new MessagingExtensionResponse
           {
               ComposeExtension = new MessagingExtensionResult
               {
                   AttachmentLayout = AttachmentLayoutTypes.List,
                   Type = "result",
                   Attachments = new List<Attachment> { finalCard.ToAttachment() }
               }
           };
       }
   
       return null;
   }
   
   // 模拟根据第一级ID获取第二级选项的业务方法
   private List<SelectionItem> GetLevel2Options(string level1Id)
   {
       return level1Id switch
       {
           "1" => new List<SelectionItem>
           {
               new SelectionItem { Type = "Level2", Id = "1-1", Name = "子分类A1" },
               new SelectionItem { Type = "Level2", Id = "1-2", Name = "子分类A2" }
           },
           "2" => new List<SelectionItem>
           {
               new SelectionItem { Type = "Level2", Id = "2-1", Name = "子分类B1" },
               new SelectionItem { Type = "Level2", Id = "2-2", Name = "子分类B2" }
           },
           _ => new List<SelectionItem>()
       };
   }
   

关键说明 #

• 通过SelectionItem.Type字段明确当前选中项的层级，确保逻辑分支清晰
• 所有返回的MessagingExtensionResult类型均为result，并使用AttachmentLayoutTypes.List布局，Teams会自动将其渲染为下拉选项列表
• 可以根据业务需求扩展更多层级，只需在SelectionItem中增加层级标识，并重写OnTeamsMessagingExtensionSelectItemAsync中的逻辑分支即可

内容的提问来源于stack exchange，提问作者VicFerron