.net core MongoDB 初试

是这样的，我们有一个场景，另一个服务器是写到MongoDB里面，我们的MVC页面要展示，需要分页展示

自己写了一个DAL

   public class MongoConnect{public string ConnectString { get; set; }}public class MongoBaseDAL<TEntity>{public MongoBaseDAL(IOptions<MongoConnect> options){ConnectString = options.Value.ConnectString;}private string ConnectString { get; set; } = "192.168.50.110:27017";protected MongoClient Create(){var client = new MongoClient($"mongodb://{ConnectString}");return client;}protected IMongoDatabase GetDatabase(string database){var client = Create();var db = client.GetDatabase(database);return db;}protected IMongoCollection<TEntity> CreateQuery(string database,string tableName){var db = GetDatabase(database);return db.GetCollection<TEntity>(tableName);}protected PageDataView<TEntity> Page(string database, string tableName, Dictionary<string, BsonValue> dictionary, int pageSize, int currentPage){var where = Builders<TEntity>.Filter.Empty;if (dictionary.Count > 0){var filterBuilder = Builders<TEntity>.Filter;List<FilterDefinition<TEntity>> listFilter = new List<FilterDefinition<TEntity>>();foreach (var pair in dictionary){listFilter.Add(filterBuilder.Eq(pair.Key, pair.Value));}where = filterBuilder.And(listFilter);}PageDataView<TEntity> result = new PageDataView<TEntity>();var query = CreateQuery(database, tableName);result.TotalRecords = (int)query.CountDocuments(where);result.TotalPages = result.TotalRecords / pageSize;if (result.TotalRecords % pageSize > 0)result.TotalPages += 1;var list = query.Find(where).Skip((currentPage - 1) * pageSize).Limit(pageSize).ToList();result.Items = list;return result;}}

 

比如有个类CreatedTableLog

那个Helper就是

    public class CreatedTableLogHelper: MongoBaseDAL<CreatedTableLog>{public static string Database = "Base";public static string Table = "CreatedTableLog";public CreatedTableLogHelper(IOptions<MongoConnect> options) : base(options){}public PageDataView<CreatedTableLog> GetListByPage(Dictionary<string, BsonValue> dictionary, int pageSize, int currentPage){return Page(Database, Table, dictionary, pageSize, currentPage);}}

在StartUp里面增加代码

            #region MongoDBservices.Configure<MongoConnect>(Configuration.GetSection("MongoConnect"));services.AddScoped(typeof(MongoBaseDAL<>));services.AddScoped<CreatedTableLogHelper>();#endregion

打开配置文件

appsettings.Development.json这个是DEBUG版本的配置文件

写入配置

  "MongoConnect": {"ConnectString": "192.168.50.110:27017"}

192.168.50.110是我测试环境是MongoDB服务器地址，端口默认

appsettings.Development.json这个是Release版本的配置文件可能这个地址就是localhost了，要对应更改

比如CreatedTableLog表有三个字段

UserId和NickName需要查询

            Dictionary<string, BsonValue> dictionary = new Dictionary<string, BsonValue>();var index = model.Start == 0 ? 1 : (model.Start / model.Length) + 1;if (model.UserId != 0){dictionary.Add("UserId", BsonInt64.Create(model.UserId));}if (!string.IsNullOrWhiteSpace(model.NickName)){dictionary.Add("NickName", BsonString.Create(model.NickName));}var result = CreatedTableLogHelper.GetListByPage(dictionary, model.Length, index);

这样你以为就ok了？no no no

会报错的，为什么同一个实体model，写入正常，读会报错_id错误呢？

因为实体model如果没有Id类型是ObjectId，会自动构建，但是你反序列化就会错误了

增加一个继承类

    public class MongoDbBase{private ObjectId _id;public ObjectId Id{get { return _id; }set { _id = value; }}}

你需要反序列化的实体对象继承

比如CreatedTableLog改为

public class CreatedTableLog: MongoDbBase

再读一下，对了吧？大功告成