查询的内容多一些，单独写
查询一条
static void GetWorker1() { var client = new MongoClient(conString); var db = client.GetDatabase(dbName); FilterDefinitionBuilder<Worker> filterBuilder = Builders<Worker>.Filter; FilterDefinition<Worker> filter = filterBuilder.Eq(doc => doc.name, "雷震子"); var worker = db.GetCollection<Worker>("worker").Find(filter).FirstOrDefault(); }
这里的eq是等于，相应的还有lt,lte等等方法。
查询集合,带分页
static void GetWorker2() { var client = new MongoClient(conString); var db = client.GetDatabase(dbName); FilterDefinitionBuilder<Worker> filterBuilder = Builders<Worker>.Filter; FilterDefinition<Worker> filter = filterBuilder.Eq(doc => doc.gender, "男"); var workers = db.GetCollection<Worker>("worker").Find(filter).SortBy(a=>a.age).Skip(0).Limit(4).ToList(); }
skip要跳过的条数，limit取几条。
获取记录条数
var count = db.GetCollection<Worker>("worker").Find(filter).CountDocuments();
获取指定字段
static void GetWorker2() { var client = new MongoClient(conString); var db = client.GetDatabase(dbName); FilterDefinitionBuilder<Worker> filterBuilder = Builders<Worker>.Filter; FilterDefinition<Worker> filter = filterBuilder.Eq(doc => doc.gender, "男"); ProjectionDefinitionBuilder<Worker> projectBuilder = Builders<Worker>.Projection; ProjectionDefinition<Worker> projection = projectBuilder.Include(doc => doc.name) .Include(doc => doc.age) .Include(doc => doc.gender); var workers1 = db.GetCollection<Worker>("worker").Find(filter).Project(projection).SortBy(a=>a.age).Skip(0).Limit(3).ToList(); foreach (var w in workers1) { var worker = BsonSerializer.Deserialize<Worker>(w); } }
用ProjectionDefinitionBuilder和ProjectionDefinition投影，指定要获取name,age,gender,然后循环反序列化成实体类。
不过这样有点麻烦，所以建议用linq，匿名类直接搞定。
var workers3 = db.GetCollection<Worker>("worker").AsQueryable().Select(doc => new { Name = doc.name, Age = doc.age, Gender = doc.gender }); foreach (var w in workers3) { }