.net core

 需要引入包：

Dapper
Dapper.Contrib
MySql.Data

　　

接口：

public interface IMySqlDapperContext : IDisposable
{
    /// <summary>
    /// MySql连接对象
    /// </summary>
    IDbConnection MySqlConnection { get; }
}

　　

/// <summary>
/// 数据库CRUD操作
/// </summary>
/// <typeparam name="T"></typeparam>
public interface IMySqlRepository<T> where T : class
{
    /// <summary>
    /// 连接
    /// </summary>
    IDbConnection Connection { get; }

    /// <summary>
    /// 上下文
    /// </summary>
    IMySqlDapperContext Context { get; }


    /// <summary>
    /// 根据主键获取数据
    /// </summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="key"></param>
    /// <param name="transaction"></param>
    /// <param name="commandTimeout"></param>
    /// <returns></returns>
    T GetByKey<T>(object key, IDbTransaction transaction = null, int? commandTimeout = null) where T : class;

    /// <summary>
    /// 添加数据
    /// </summary>
    /// <param name="entity"></param>
    /// <param name="transaction"></param>
    /// <param name="commandTimeout"></param>
    /// <returns></returns>
    long Add(T entity, IDbTransaction transaction = null, int? commandTimeout = null);

    /// <summary>
    /// 
    /// </summary>
    /// <param name="entity"></param>
    /// <param name="transaction"></param>
    /// <param name="commandTimeout"></param>
    void Update(T entity, IDbTransaction transaction = null, int? commandTimeout = null);

    /// <summary>
    /// 删除单条数据
    /// </summary>
    /// <param name="entity"></param>
    /// <param name="transaction"></param>
    /// <param name="commandTimeout"></param>
    void Remove(T entity, IDbTransaction transaction = null, int? commandTimeout = null);

    /// <summary>
    /// 根据主键获取数据
    /// </summary>
    /// <param name="key"></param>
    /// <param name="transaction"></param>
    /// <param name="commandTimeout"></param>
    /// <returns></returns>
    T GetByKey(object key, IDbTransaction transaction = null, int? commandTimeout = null);

    /// <summary>
    /// 获取所有数据
    /// </summary>
    /// <param name="transaction"></param>
    /// <param name="commandTimeout"></param>
    /// <returns></returns>
    IEnumerable<T> GetAll(IDbTransaction transaction = null, int? commandTimeout = null);

    /// <summary>
    /// 根据条件获取数据列表
    /// </summary>
    /// <param name="where"></param>
    /// <param name="order"></param>
    /// <param name="transaction"></param>
    /// <param name="commandTimeout"></param>
    /// <returns></returns>
    IEnumerable<T> GetBy(object where = null, object order = null, IDbTransaction transaction = null, int? commandTimeout = null);

    IEnumerable<T> GetBy<T>(object sql = null, object param = null, IDbTransaction transaction = null, int? commandTimeout = null) where T : class;

    T QuerySingleOrDefault<T>(string sql = null, object param = null, IDbTransaction transaction = null, int? commandTimeout = null) where T : class;

    /// <summary>
    /// 查询数据列表
    /// </summary>
    /// <param name="sql"></param>
    /// <param name="transaction"></param>
    /// <param name="commandTimeout"></param>
    /// <returns></returns>
    IEnumerable<dynamic> Query(string sql, IDbTransaction transaction = null, int? commandTimeout = null);
        
    /// <summary>
    /// 查询数据列表
    /// </summary>
    /// <param name="sql"></param>
    /// <param name="transaction"></param>
    /// <param name="commandTimeout"></param>
    /// <returns></returns>
    IEnumerable<T> Query<T>(string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null) where T : class;
        
    /// <summary>
    /// 查询数据列表
    /// </summary>
    /// <typeparam name="TFirst"></typeparam>
    /// <typeparam name="TSecond"></typeparam>
    /// <typeparam name="TReturn"></typeparam>
    /// <param name="sql"></param>
    /// <param name="map"></param>
    /// <param name="transaction"></param>
    /// <param name="commandTimeout"></param>
    /// <returns></returns>
    IEnumerable<TReturn> Query<TFirst, TSecond, TReturn>(string sql, Func<TFirst, TSecond, TReturn> map, object param = null, IDbTransaction transaction = null, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null);


    IEnumerable<TReturn> Query<TFirst, TSecond, TThird, TReturn>(string sql, Func<TFirst, TSecond, TThird, TReturn> map, object param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null);

    IEnumerable<TReturn> Query<TFirst, TSecond, TThird, TFourth, TFifth, TReturn>(string sql, Func<TFirst, TSecond, TThird, TFourth, TFifth, TReturn> map, object param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null);

    IEnumerable<TReturn> Query<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TReturn>(string sql, Func<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TReturn> map, object param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null);

    IEnumerable<TReturn> Query<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TSeventh, TReturn>(string sql, Func<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TSeventh, TReturn> map, object param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null);
    /// <summary>
    /// 查询数据列表
    /// </summary>
    /// <typeparam name="TFirst"></typeparam>
    /// <typeparam name="TSecond"></typeparam>
    /// <typeparam name="TThird"></typeparam>
    /// <typeparam name="TFourth"></typeparam>
    /// <typeparam name="TReturn"></typeparam>
    /// <param name="sql"></param>
    /// <param name="map"></param>
    /// <param name="param"></param>
    /// <param name="transaction"></param>
    /// <param name="splitOn"></param>
    /// <param name="commandTimeout"></param>
    /// <param name="commandType"></param>
    /// <returns></returns>
    IEnumerable<TReturn> Query<TFirst, TSecond, TThird, TFourth, TReturn>(string sql, Func<TFirst, TSecond, TThird, TFourth, TReturn> map, object param = null, IDbTransaction transaction = null, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null);

    /// <summary>
    /// 执行sql
    /// </summary>
    /// <param name="sql"></param>
    /// <param name="transaction"></param>
    /// <param name="commandTimeout"></param>
    /// <returns></returns>
    int Excute(string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null);

    /// <summary>
    /// 返回单个参数
    /// </summary>
    /// <param name="sql"></param>
    /// <param name="transaction"></param>
    /// <param name="commandTimeout"></param>
    /// <returns></returns>
    object ExcuteScalar(string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null);
}

　　

实现：

    /// <summary>
    /// 连接字符串
    /// </summary>
    private string ConnectionString;

    /// <summary>
    /// 连接
    /// </summary>
    private IDbConnection Connection;

    /// <summary>
    /// 构造函数注入IConfiguration
    /// </summary>
    /// <param name="configuration"></param>
    public MySqlDapperContext(IConfiguration configuration)
    {
        ConnectionString = configuration["AppSetting:MySqlConnectionString"];
    }

    public IDbConnection MySqlConnection {
        get {
            if (Connection == null || Connection.State == ConnectionState.Closed)
            {
                Connection = new MySqlConnection(ConnectionString);
            }
            if (Connection.State == ConnectionState.Closed)
            {
                Connection.Open();
            }
            return Connection;
        }
    }

    /// <summary>
    /// 释放链接
    /// </summary>
    public void Dispose()
    {
        if (Connection != null && Connection.State == ConnectionState.Open)
        {
            Connection.Close();
        }
    }
}

　　

public class MySqlRepository<T> : IMySqlRepository<T> where T : class
{
    /// <summary>
    /// 存储appsetting.json里的数据库连接字符串
    /// </summary>
    private string ConnectionString;

    public IMySqlDapperContext Context { get; private set; }

    public IDbConnection Connection
    {
        get
        {
            return Context.MySqlConnection;
        }
    }

    public MySqlRepository(IMySqlDapperContext context)
    {
        Context = context;
        ConnectionString = context.MySqlConnection.ConnectionString;
    }

    public virtual T GetByKey<T>(object id, IDbTransaction transaction = null, int? commandTimeout = null) where T : class
    {
        if (id == null)
        {
            throw new ArgumentNullException("id");
        }
        return Connection.Get<T>(id, transaction: transaction, commandTimeout: commandTimeout);
    }

    public long Add(T entity, IDbTransaction transaction = null, int? commandTimeout = null)
    {
        if (entity == null)
        {
            throw new ArgumentNullException("entity", "Add to DB null entity");
        }
        var res = Connection.Insert(entity, transaction: transaction, commandTimeout: commandTimeout);
        return res;
    }

    public virtual void Update(T entity, IDbTransaction transaction = null, int? commandTimeout = null)
    {
        if (entity == null)
        {
            throw new ArgumentNullException("entity", "Update in DB null entity");
        }
        Connection.Update(entity, transaction: transaction, commandTimeout: commandTimeout);
    }

    public virtual void Remove(T entity, IDbTransaction transaction = null, int? commandTimeout = null)
    {
        if (entity == null)
        {
            throw new ArgumentNullException("entity", "Remove in DB null entity");
        }
        Connection.Delete(entity, transaction: transaction, commandTimeout: commandTimeout);
    }

    public virtual T GetByKey(object id, IDbTransaction transaction = null, int? commandTimeout = null)
    {
        if (id == null)
        {
            throw new ArgumentNullException("id");
        }
        return Connection.Get<T>(id, transaction: transaction, commandTimeout: commandTimeout);
    }

    public virtual IEnumerable<T> GetAll(IDbTransaction transaction = null, int? commandTimeout = null)
    {
        return Connection.GetAll<T>(transaction: transaction, commandTimeout: commandTimeout);
    }


    public virtual T QuerySingleOrDefault<T>(string sql = null, object param = null, IDbTransaction transaction = null, int? commandTimeout = null) where T : class
    {
        return Connection.QuerySingleOrDefault<T>(sql, param, transaction: transaction, commandTimeout: commandTimeout);
    }

    public virtual IEnumerable<T> GetBy(object where = null, object order = null, IDbTransaction transaction = null, int? commandTimeout = null)
    {
        return Connection.Query<T>(where.ToString(), commandTimeout: commandTimeout);
    }

    public virtual IEnumerable<T> GetBy<T>(object sql = null, object param = null, IDbTransaction transaction = null, int? commandTimeout = null) where T : class
    {
        return Connection.Query<T>(sql.ToString(), param: param, transaction: transaction, commandTimeout: commandTimeout);
    }


    public IEnumerable<dynamic> Query(string sql, IDbTransaction transaction = null, int? commandTimeout = null)
    {
        return Connection.Query<dynamic>(sql);
    }

    public IEnumerable<T> Query<T>(string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null) where T : class
    {
        return Connection.Query<T>(sql, param: param, transaction: transaction);
    }

    public IEnumerable<TReturn> Query<TFirst, TSecond, TReturn>(string sql, Func<TFirst, TSecond, TReturn> map, object param = null, IDbTransaction transaction = null, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null)
    {
        return Connection.Query<TFirst, TSecond, TReturn>(sql, map, param: param, transaction: transaction, splitOn: splitOn, commandType: commandType);
    }
    public IEnumerable<TReturn> Query<TFirst, TSecond, TThird, TReturn>(string sql, Func<TFirst, TSecond, TThird, TReturn> map, object param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null)
    {
        return Connection.Query<TFirst, TSecond, TThird, TReturn>(sql, map, param: param, transaction: transaction, splitOn: splitOn, commandType: commandType);
    }

    public IEnumerable<TReturn> Query<TFirst, TSecond, TThird, TFourth, TReturn>(string sql, Func<TFirst, TSecond, TThird, TFourth, TReturn> map, object param = null, IDbTransaction transaction = null, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null)
    {
        return Connection.Query<TFirst, TSecond, TThird, TFourth, TReturn>(sql, map, param: param, transaction: transaction, splitOn: splitOn, commandType: commandType);
    }

    public IEnumerable<TReturn> Query<TFirst, TSecond, TThird, TFourth, TFifth, TReturn>(string sql, Func<TFirst, TSecond, TThird, TFourth, TFifth, TReturn> map, object param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null)
    {
        return Connection.Query<TFirst, TSecond, TThird, TFourth, TFifth, TReturn>(sql, map, param: param, transaction: transaction, splitOn: splitOn, commandType: commandType);

    }
    public IEnumerable<TReturn> Query<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TReturn>(string sql, Func<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TReturn> map, object param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null)
    {
        return Connection.Query<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TReturn>(sql, map, param: param, transaction: transaction, splitOn: splitOn, commandType: commandType);
    }
    public IEnumerable<TReturn> Query<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TSeventh, TReturn>(string sql, Func<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TSeventh, TReturn> map, object param = null, IDbTransaction transaction = null, bool buffered = true, string splitOn = "Id", int? commandTimeout = null, CommandType? commandType = null)
    {
        return Connection.Query<TFirst, TSecond, TThird, TFourth, TFifth, TSixth, TSeventh, TReturn>(sql, map, param: param, transaction: transaction, splitOn: splitOn, commandType: commandType);
    }

    public int Excute(string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null)
    {
        return Connection.Execute(sql, param: param, transaction: transaction);
    }
    public object ExcuteScalar(string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null)
    {
        return Connection.ExecuteScalar(sql, param: param, transaction: transaction, commandTimeout: commandTimeout);
    }

    public GridReader QueryMultiple(string sql, object param = null, IDbTransaction transaction = null, int? commandTimeout = null)
    {

        return Connection.QueryMultiple(sql, param: param, transaction: transaction, commandTimeout: commandTimeout);
    }
}