MongoDB c#驱动程序的字段投影

本文关键字：字段 投影 驱动程序 MongoDB | 更新日期: 2023-09-27 18:02:08

嗨，我在mongoDB中有一个集合，我想从中只获得部分字段，我创建了一个类，我正在向mongoDB插入数据

ClassCode: 

public class  FrameDocument
{
    public ObjectId _id { get; set; }
    public Nullable<System.DateTime> FrameTimeStamp { get; set; }
    public Nullable<int> ActivePick { get; set; }
    public Nullable<int> TraderId { get; set; }
    public Nullable<int> EventCodeId { get; set; }
    public byte[] Frame { get; set; }
    public int ServerUserId { get; set; }
    public int SesionId { get; set; }
    public string TraderName { get; set; }
    public string ServerUserName { get; set; }

}
这是插入代码: 
               FrameDocument frameDoc = new FrameDocument();
            frameDoc.Frame = imageBA;
            frameDoc.EventCodeId = 1;
            frameDoc.SesionId = 1;
            frameDoc.FrameTimeStamp = DateTime.Now;
            frameDoc.ServerUserId = (int)toMongoDt.Rows[0]["ServerUserId"];
            frameDoc.TraderId = (int)toMongoDt.Rows[0]["TraderId"];
            frameDoc.ActivePick = (int)toMongoDt.Rows[0]["ActivePick"];
            frameDoc.TraderName = (string)toMongoDt.Rows[0]["TraderName"];
            frameDoc.ServerUserName = (string)toMongoDt.Rows[0]   ["ServerUserName"];
            var mongoCon = "mongodb://127.0.0.1";
            MongoClient client = new MongoClient(mongoCon);
            var db = client.GetDatabase("Video");
            var frameCollection = db.GetCollection<FrameDocument>("Frame");
            frameCollection.InsertOne(frameDoc);

**现在我从这个代码集合得到所有的字段，但我想离开类的框架字段，我试图建立不同的类没有这个字段，但我不知道如何不接收框架字段**

                var collection = db.GetCollection<BsonDocument>("Frame");
            var builder = Builders<BsonDocument>.Filter;
            var filter = builder.Eq("SesionId", 1)
                & builder.Eq("TraderId", 125)
                 & builder.Eq("ServerUserId", 1)
                & builder.Lt("FrameTimeStamp", sing.eDate)
                & builder.Gt("FrameTimeStamp", sing.sDate);
            var result = collection.Find(filter).ToList();

有人能帮忙吗?

MongoDB c#驱动程序的字段投影

请看:

   _result = _collection.Find(o => o._id == _id)
            .Project<FrameDocumentNoFrameField>  
          (Builders<FrameDocument>.Projection.Exclude(f => f.Frame)).ToList();

其中FrameDocumentNoFrameField是一个没有Frame字段的类

源这里

#例子:模型类 

    public class Company
    {
        public string CompanyId { get; set; }
        public string CompanyName { get; set; }
        public List<CompanySettings>{ get; set; }
    }
   [BsonIgnoreExtraElements]
    public class CompanySettings
    {
        public CompanySetupType CompanySetupTypeId { get; set; }
        public List<string> CompanyEmployee{ get; set; }
    }

#现在创建一个想要读取值的投影类

[BsonIgnoreExtraElements]
    public class CompanySettingsProjectionModel
    {  
        public List<CompanySettings> CompanySettings { get; set; }
    }

#创建投影后，使用Builders从mongo获取数据

     public async Task<CompanySettings> GetCompanySettings(string companyId, short CompanySetupTypeId)
        {
            var filter = BaseFilter(accountId);
            var projection = Builders<Company>.Projection
            .Include(x => x.Id)
            .Include(x => x.CompanySettings);
            FindOptions<Company, CompanySettingsProjectionModel> findOptions = new FindOptions<Company, CompanySettingsProjectionModel>()
            {
                Projection = projection
            };
            var companySettings = await (await Collection.FindAsync(filter, findOptions)).FirstOrDefaultAsync();
            if (companySettings != null && companySettings.CompanySettings != null && companySettings.CompanySettings.Any())
            {
                return companySettings.CompanySettings .FirstOrDefault(x => (int)x.CompanySetupTypeId == CompanySetupTypeId);
            }
            return default;
        }
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