using System;
using System.Collections.Generic;
using System.Linq;
using MongoDB;


/// <summary>
/// 對Mongo和MongoDatabase的包裝類
/// </summary>
public class MyMongoDb : IDisposable
{
    private Mongo _mongo;
    private IMongoDatabase _db;
    private static string connectionString = "Server=127.0.0.1;mydb";
    private static readonly string _connectionString = connectionString.Split(';')[0];// "Server=127.0.0.1";
    private static readonly string _dbName = connectionString.Split(';')[1];



    public MyMongoDb()
        : this(_connectionString, _dbName)
    {
    }

    public MyMongoDb(string dbName)
        : this(_connectionString, dbName)
    {
    }

	/// <summary>
	/// 建構函式。根據指定連線字串和資料庫名
	/// </summary>
	/// <param name="connectionString">連線字串</param>
	/// <param name="dbName">資料庫名，可為空，但必須在任何操作資料庫之前要呼叫UseDb()方法</param>
	public MyMongoDb(string connectionString, string dbName)
	{
		if( string.IsNullOrEmpty(connectionString) )
			throw new ArgumentNullException("connectionString");

		_mongo = new Mongo(connectionString);

		// 立即連線 MongoDB
		_mongo.Connect();

		if( string.IsNullOrEmpty(dbName) == false )
			_db = _mongo.GetDatabase(dbName);
	}

	/// <summary>
	/// 切換到指定的資料庫
	/// </summary>
	/// <param name="dbName"></param>
	/// <returns></returns>
	public IMongoDatabase UseDb(string dbName)
	{
		if( string.IsNullOrEmpty(dbName) )
			throw new ArgumentNullException("dbName");

		_db = _mongo.GetDatabase(dbName);
		return _db;
	}

	/// <summary>
	/// 獲取當前連線的資料庫
	/// </summary>
	public IMongoDatabase CurrentDb
	{
		get
		{
			if( _db == null )
				throw new Exception("當前連線沒有指定任何資料庫。請在建構函式中指定資料庫名或者呼叫UseDb()方法切換資料庫。");

			return _db;
		}
	}

	/// <summary>
	/// 獲取當前連線資料庫的指定集合【依據型別】
	/// </summary>
	/// <typeparam name="T"></typeparam>
	/// <returns></returns>
	public IMongoCollection<T> GetCollection<T>() where T : class
	{
		return this.CurrentDb.GetCollection<T>();
	}

	/// <summary>
	/// 獲取當前連線資料庫的指定集合【根據指定名稱】
	/// </summary>
	/// <typeparam name="T"></typeparam>
	/// <param name="name">集合名稱</param>
	/// <returns></returns>
	public IMongoCollection<T> GetCollection<T>(string name) where T : class
	{
		return this.CurrentDb.GetCollection<T>(name);
	}

	public void Dispose()
	{
		if( _mongo != null ) {
			_mongo.Dispose();
			_mongo = null;
		}
	}	
}
 

使用連結類

        public void Insert(USER user)
        {
            using (MyMongoDb mdb = new MyMongoDb())
            {
                var collection = mdb.GetCollection<USER>();

                collection.Insert(user);
            }
        }