C# 扩展方法——mysql-dapper(MySqlMapperExtensions)

其他扩展方法详见：https://www.cnblogs.com/zhuanjiao/p/12060937.html

反射比较耗费性能，反射得到属性进行缓存

根据反射得到的属性，进行动态拼接sql语句

说明：未找到原文链接，未加出处。

下面篇幅我只加了一个扩展方法。

using Dapper;
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Data;
using System.Dynamic;
using System.Linq;
using System.Reflection;
using System.Threading.Tasks;

namespace CoSubject.Common.DapperExtensions
{
    public static class MySqlMapperExtensions
    {
        private static readonly ConcurrentDictionary<Type, List<PropertyInfo>> _paramCache = new ConcurrentDictionary<Type, List<PropertyInfo>>();

        /// <summary>
        /// Insert data into table.
        /// </summary>
        /// <param name="connection"></param>
        /// <param name="data"></param>
        /// <param name="table"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static int Insert(this IDbConnection connection, dynamic data, string table, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            var obj = data as object;
            var properties = GetProperties(obj);
            var columns = string.Join(",", properties.Select(p => table + "." + p));
            var values = string.Join(",", properties.Select(p => "@" + p));
            var sql = string.Format("insert into {0} ({1}) values ({2})", table, columns, values);
            return connection.Execute(sql, obj, transaction, commandTimeout);
        }

        public static int InsertWithOutPrimaryKey(this IDbConnection connection, dynamic data, string table, string primaryKey, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            var obj = data as object;
            var properties = GetProperties(obj);
            properties.Remove(primaryKey);
            var columns = string.Join(",", properties.Select(p => table + "." + p));
            var values = string.Join(",", properties.Select(p => "@" + p));
            var sql = string.Format("insert into {0} ({1}) values ({2})", table, columns, values);
            return connection.Execute(sql, obj, transaction, commandTimeout);
        }

        /// <summary>
        /// Insert data async into table.
        /// </summary>
        /// <param name="connection"></param>
        /// <param name="data"></param>
        /// <param name="table"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static Task<int> InsertAsync(this IDbConnection connection, dynamic data, string table, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            var obj = data as object;
            var properties = GetProperties(obj);
            var columns = string.Join(",", properties);
            var values = string.Join(",", properties.Select(p => "@" + p));
            var sql = string.Format("insert into {0} ({1}) values ({2}))", table, columns, values);
            return connection.ExecuteAsync(sql, obj, transaction, commandTimeout);
        }

        /// <summary>
        /// Updata data for table with a specified condition.
        /// </summary>
        /// <param name="connection"></param>
        /// <param name="data"></param>
        /// <param name="condition"></param>
        /// <param name="table"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static int Update(this IDbConnection connection, dynamic data, dynamic condition, string table, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            var obj = data as object;
            var conditionObj = condition as object;
            var updatePropertyInfos = GetPropertyInfos(obj);
            var wherePropertyInfos = GetPropertyInfos(conditionObj);
            var updateProperties = updatePropertyInfos.Select(p => p.Name);
            var whereProperties = wherePropertyInfos.Select(p => p.Name);
            var updateFields = string.Join(",", updateProperties.Select(p => p + " = @" + p));
            var whereFields = string.Empty;

            if (whereProperties.Any())
            {
                whereFields = " where " + string.Join(" and ", whereProperties.Select(p => p + " = @w_" + p));
            }
            var sql = string.Format("update {0} set {1}{2}", table, updateFields, whereFields);
            var parameters = new DynamicParameters(data);
            var expandoObject = new ExpandoObject() as IDictionary<string, object>;
            wherePropertyInfos.ForEach(p => expandoObject.Add("w_" + p.Name, p.GetValue(conditionObj, null)));
            parameters.AddDynamicParams(expandoObject);
            return connection.Execute(sql, parameters, transaction, commandTimeout);
        }

        /// <summary>
        /// 更新自定义列数据
        /// </summary>
        /// <param name="connection"></param>
        /// <param name="data"></param>
        /// <param name="updateColumns">自定义列名</param>
        /// <param name="condition"></param>
        /// <param name="table"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static int Update(this IDbConnection connection, dynamic data, dynamic condition, string table, List<string> updateColumns, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            if (updateColumns == null || updateColumns.Count == 0)
                throw new ArgumentException("updateColumns 必须设定要更新的列！", "updateColumns");
            var obj = data as object;
            var conditionObj = condition as object;
            var updatePropertyInfos = GetPropertyInfos(obj);
            var wherePropertyInfos = GetPropertyInfos(conditionObj);
            var updateProperties = updatePropertyInfos.Select(p => p.Name).Intersect(updateColumns);
            var whereProperties = wherePropertyInfos.Select(p => p.Name);
            var updateFields = string.Join(",", updateProperties.Select(p => p + " = @" + p));
            var whereFields = string.Empty;
            if (whereProperties.Any())
            {
                whereFields = " where " + string.Join(" and ", whereProperties.Select(p => p + " = @w_" + p));
            }
            var sql = string.Format("update {0} set {1}{2}", table, updateFields, whereFields);
            var parameters = new DynamicParameters(data);
            var expandoObject = new ExpandoObject() as IDictionary<string, object>;
            wherePropertyInfos.ForEach(p => expandoObject.Add("w_" + p.Name, p.GetValue(conditionObj, null)));
            parameters.AddDynamicParams(expandoObject);
            return connection.Execute(sql, parameters, transaction, commandTimeout);
        }

        public static int UpdateWithColumns(this IDbConnection connection, dynamic data, object condition, string table, List<string> updateColumns, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            if (updateColumns == null || updateColumns.Count == 0)
                throw new ArgumentException("updateColumns 必须设定要更新的列！", "updateColumns");
            var obj = data as object;
            var conditionObj = condition as object;
            var updatePropertyInfos = GetPropertyInfos(obj);
            var wherePropertyInfos = GetPropertyInfos(conditionObj);
            var updateProperties = updatePropertyInfos.Select(p => p.Name).Intersect(updateColumns);
            var whereProperties = wherePropertyInfos.Select(p => p.Name);
            var updateFields = string.Join(",", updateProperties.Select(p => p + " = @" + p));
            var whereFields = string.Empty;
            if (whereProperties.Any())
            {
                whereFields = " where " + string.Join(" and ", whereProperties.Select(p => p + " = @w_" + p));
            }
            var sql = string.Format("update {0} set {1}{2}", table, updateFields, whereFields);
            var parameters = new DynamicParameters(data);
            var expandoObject = new ExpandoObject() as IDictionary<string, object>;
            wherePropertyInfos.ForEach(p => expandoObject.Add("w_" + p.Name, p.GetValue(conditionObj, null)));
            parameters.AddDynamicParams(expandoObject);
            return connection.Execute(sql, parameters, transaction, commandTimeout);
        }

        /// <summary>
        /// Updata data async for table with a specified condition.
        /// </summary>
        /// <param name="connection"></param>
        /// <param name="data"></param>
        /// <param name="condition"></param>
        /// <param name="table"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static Task<int> UpdateAsync(this IDbConnection connection, dynamic data, dynamic condition, string table, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            var obj = data as object;
            var conditionObj = condition as object;
            var updatePropertyInfos = GetPropertyInfos(obj);
            var wherePropertyInfos = GetPropertyInfos(conditionObj);
            var updateProperties = updatePropertyInfos.Select(p => p.Name);
            var whereProperties = wherePropertyInfos.Select(p => p.Name);
            var updateFields = string.Join(",", updateProperties.Select(p => p + " = @" + p));
            var whereFields = string.Empty;
            if (whereProperties.Any())
            {
                whereFields = " where " + string.Join(" and ", whereProperties.Select(p => p + " = @w_" + p));
            }
            var sql = string.Format("update {0} set {1}{2}", table, updateFields, whereFields);
            var parameters = new DynamicParameters(data);
            var expandoObject = new ExpandoObject() as IDictionary<string, object>;
            wherePropertyInfos.ForEach(p => expandoObject.Add("w_" + p.Name, p.GetValue(conditionObj, null)));
            parameters.AddDynamicParams(expandoObject);
            return connection.ExecuteAsync(sql, parameters, transaction, commandTimeout);
        }

        /// <summary>
        /// Delete data from table with a specified condition.
        /// </summary>
        /// <param name="connection"></param>
        /// <param name="condition"></param>
        /// <param name="table"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static int Delete(this IDbConnection connection, dynamic condition, string table, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            var conditionObj = condition as object;
            var whereFields = string.Empty;
            var whereProperties = GetProperties(conditionObj);
            if (whereProperties.Count > 0)
            {
                whereFields = " where " + string.Join(" and ", whereProperties.Select(p => p + " = @" + p));
            }
            var sql = string.Format("delete from {0}{1}", table, whereFields);
            return connection.Execute(sql, conditionObj, transaction, commandTimeout);
        }

        /// <summary>
        /// Delete data async from table with a specified condition.
        /// </summary>
        /// <param name="connection"></param>
        /// <param name="condition"></param>
        /// <param name="table"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static Task<int> DeleteAsync(this IDbConnection connection, dynamic condition, string table, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            var conditionObj = condition as object;
            var whereFields = string.Empty;
            var whereProperties = GetProperties(conditionObj);
            if (whereProperties.Count > 0)
            {
                whereFields = " where " + string.Join(" and ", whereProperties.Select(p => p + " = @" + p));
            }
            var sql = string.Format("delete from {0}{1}", table, whereFields);
            return connection.ExecuteAsync(sql, conditionObj, transaction, commandTimeout);
        }

        /// <summary>
        /// Get data count from table with a specified condition.
        /// </summary>
        /// <param name="connection"></param>
        /// <param name="condition"></param>
        /// <param name="table"></param>
        /// <param name="isOr"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static int GetCount(this IDbConnection connection, object condition, string table, bool isOr = false, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            return QueryList<int>(connection, condition, table, "count(1)", isOr, transaction, commandTimeout).Single();
        }

        /// <summary>
        /// Get data count async from table with a specified condition.
        /// </summary>
        /// <param name="connection"></param>
        /// <param name="condition"></param>
        /// <param name="table"></param>
        /// <param name="isOr"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static Task<int> GetCountAsync(this IDbConnection connection, object condition, string table, bool isOr = false, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            return QueryListAsync<int>(connection, condition, table, "count(*)", isOr, transaction, commandTimeout).ContinueWith<int>(t => t.Result.Single());
        }

        /// <summary>
        /// Query a list of data from table with a specified condition.
        /// </summary>
        /// <param name="connection"></param>
        /// <param name="condition"></param>
        /// <param name="table"></param>
        /// <param name="columns"></param>
        /// <param name="isOr"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static IEnumerable<dynamic> QueryList(this IDbConnection connection, dynamic condition, string table, string columns = "*", bool isOr = false, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            return QueryList<dynamic>(connection, condition, table, columns, isOr, transaction, commandTimeout);
        }

        /// <summary>
        /// Query a list of data async from table with a specified condition.
        /// </summary>
        /// <param name="connection"></param>
        /// <param name="condition"></param>
        /// <param name="table"></param>
        /// <param name="columns"></param>
        /// <param name="isOr"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static Task<IEnumerable<dynamic>> QueryListAsync(this IDbConnection connection, dynamic condition, string table, string columns = "*", bool isOr = false, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            return QueryListAsync<dynamic>(connection, condition, table, columns, isOr, transaction, commandTimeout);
        }

        /// <summary>
        /// Query a list of data from table with specified condition.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="connection"></param>
        /// <param name="condition"></param>
        /// <param name="table"></param>
        /// <param name="columns"></param>
        /// <param name="isOr"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static IEnumerable<T> QueryList<T>(this IDbConnection connection, object condition, string table, string columns = "*", bool isOr = false, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            return connection.Query<T>(BuildQuerySQL(condition, table, columns, isOr), condition, transaction, true, commandTimeout);
        }

        /// <summary>
        /// Query a list of data async from table with specified condition.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="connection"></param>
        /// <param name="condition"></param>
        /// <param name="table"></param>
        /// <param name="columns"></param>
        /// <param name="isOr"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static Task<IEnumerable<T>> QueryListAsync<T>(this IDbConnection connection, object condition, string table, string columns = "*", bool isOr = false, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            return connection.QueryAsync<T>(BuildQuerySQL(condition, table, columns, isOr), condition, transaction, commandTimeout);
        }

        /// <summary>
        /// Query paged data from a single table.
        /// </summary>
        /// <param name="connection"></param>
        /// <param name="condition"></param>
        /// <param name="table"></param>
        /// <param name="orderBy"></param>
        /// <param name="pageIndex"></param>
        /// <param name="pageSize"></param>
        /// <param name="columns"></param>
        /// <param name="isOr"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static IEnumerable<dynamic> QueryPaged(this IDbConnection connection, dynamic condition, string table, string orderBy, int pageIndex, int pageSize, string columns = "*", bool isOr = false, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            return QueryPaged<dynamic>(connection, condition, table, orderBy, pageIndex, pageSize, columns, isOr, transaction, commandTimeout);
        }

        /// <summary>
        /// Query paged data async from a single table.
        /// </summary>
        /// <param name="connection"></param>
        /// <param name="condition"></param>
        /// <param name="table"></param>
        /// <param name="orderBy"></param>
        /// <param name="pageIndex"></param>
        /// <param name="pageSize"></param>
        /// <param name="columns"></param>
        /// <param name="isOr"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static Task<IEnumerable<dynamic>> QueryPagedAsync(this IDbConnection connection, dynamic condition, string table, string orderBy, int pageIndex, int pageSize, string columns = "*", bool isOr = false, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            return QueryPagedAsync<dynamic>(connection, condition, table, orderBy, pageIndex, pageSize, columns, isOr, transaction, commandTimeout);
        }

        /// <summary>
        /// Query paged data from a single table.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="connection"></param>
        /// <param name="condition"></param>
        /// <param name="table"></param>
        /// <param name="orderBy"></param>
        /// <param name="pageIndex"></param>
        /// <param name="pageSize"></param>
        /// <param name="columns"></param>
        /// <param name="isOr"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static IEnumerable<T> QueryPaged<T>(this IDbConnection connection, dynamic condition, string table, string orderBy, int pageIndex = 1, int pageSize = 20, string columns = "*", bool isOr = false, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            var conditionObj = condition as object;
            var whereFields = string.Empty;
            var properties = GetProperties(conditionObj);
            if (properties.Count > 0)
            {
                var separator = isOr ? " OR " : " AND ";
                whereFields = " WHERE " + string.Join(separator, properties.Select(p => p + " = @" + p));
            }
            var sql = string.Format("SELECT {0} FROM {2}{3} ORDER BY {1} LIMIT {4},{5} ", columns, orderBy, table, whereFields, (pageIndex - 1) * pageSize, pageSize);
            return connection.Query<T>(sql, conditionObj, transaction, true, commandTimeout);
        }

        /// <summary>
        /// Query paged data from a single table.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="connection"></param>
        /// <param name="condition"></param>
        /// <param name="table"></param>
        /// <param name="orderBy"></param>
        /// <param name="count"></param>
        /// <param name="pageIndex"></param>
        /// <param name="pageSize"></param>
        /// <param name="columns"></param>
        /// <param name="isOr"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static IEnumerable<T> QueryPagedWithAllCount<T>(this IDbConnection connection, dynamic condition, string table, string orderBy, out int count, int pageIndex = 1, int pageSize = 20, string columns = "*", bool isOr = false, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            count = 0;
            var conditionObj = condition as object;
            var whereFields = string.Empty;
            var properties = GetProperties(conditionObj);
            if (properties.Count > 0)
            {
                var separator = isOr ? " OR " : " AND ";
                whereFields = " WHERE " + string.Join(separator, properties.Select(p => p + " = @" + p));
            }
            var sql = string.Format("SELECT SQL_CALC_FOUND_ROWS {0} FROM {2}{3} ORDER BY {1} LIMIT {4},{5};SELECT FOUND_ROWS();", columns, orderBy, table, whereFields, (pageIndex - 1) * pageSize, pageSize);
            var multi = connection.QueryMultiple(sql, conditionObj, transaction, commandTimeout);
            var ret = multi.Read<T>();
            count = multi.ReadFirst<int>();
            return ret;
        }

        /// <summary>
        /// Query paged data from  multiple or single table and return the total number of entries
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="connection"></param>
        /// <param name="sql">拼接好的完整sql语句</param>
        /// <param name="condition"></param>
        /// <param name="count"></param>
        /// <param name="transaction"></param>
        /// <returns></returns>
        public static IEnumerable<T> QueryPagedBySqlWithCount<T>(this IDbConnection connection, string sql, dynamic condition, out int count, IDbTransaction transaction = null)
        {
            var conditionObj = condition as object;
            count = 0;
            // 删除原来sql中的select
            sql = sql.Trim().Remove(0, 6);
            // 去表末尾的分号
            sql = sql.TrimEnd(new char[] { ';' });
            sql = string.Format("SELECT SQL_CALC_FOUND_ROWS {0};SELECT FOUND_ROWS();", sql);
            var multi = connection.QueryMultiple(sql, conditionObj, transaction);
            // 需要按照顺序获取
            var ret = multi.Read<T>();
            count = multi.ReadFirst<int>();
            return ret;
        }

        /// <summary>
        /// Query paged data async from a single table.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="connection"></param>
        /// <param name="condition"></param>
        /// <param name="table"></param>
        /// <param name="orderBy"></param>
        /// <param name="pageIndex"></param>
        /// <param name="pageSize"></param>
        /// <param name="columns"></param>
        /// <param name="isOr"></param>
        /// <param name="transaction"></param>
        /// <param name="commandTimeout"></param>
        /// <returns></returns>
        public static Task<IEnumerable<T>> QueryPagedAsync<T>(this IDbConnection connection, dynamic condition, string table, string orderBy, int pageIndex, int pageSize, string columns = "*", bool isOr = false, IDbTransaction transaction = null, int? commandTimeout = null)
        {
            var conditionObj = condition as object;
            var whereFields = string.Empty;
            var properties = GetProperties(conditionObj);
            if (properties.Count > 0)
            {
                var separator = isOr ? " OR " : " AND ";
                whereFields = " WHERE " + string.Join(separator, properties.Select(p => p + " = @" + p));
            }
            var sql = string.Format("SELECT {0} FROM {2}{3} ORDER BY {1} LIMIT {4},{5} ", columns, orderBy, table, whereFields, (pageIndex - 1) * pageSize, pageSize);
            return connection.QueryAsync<T>(sql, conditionObj, transaction, commandTimeout);
        }

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

        public static string GetLastId(this IDbConnection connection)
        {
            string sql = "select last_insert_id();";
            return connection.QueryFirst<string>(sql);
        }

        private static string BuildQuerySQL(dynamic condition, string table, string selectPart = "*", bool isOr = false)
        {
            var conditionObj = condition as object;
            var properties = GetProperties(conditionObj);
            if (properties.Count == 0)
            {
                return string.Format("SELECT {1} FROM {0}", table, selectPart);
            }
            var separator = isOr ? " OR " : " AND ";
            var wherePart = string.Join(separator, properties.Select(p => p + " = @" + p));
            return string.Format("SELECT {2} FROM {0} WHERE {1}", table, wherePart, selectPart);
        }

        private static List<string> GetProperties(object obj)
        {
            if (obj == null)
            {
                return new List<string>();
            }
            if (obj is DynamicParameters)
            {
                return (obj as DynamicParameters).ParameterNames.ToList();
            }
            if (obj is ExpandoObject)
            {
                var expandoDic = (IDictionary<string, object>)obj;
                return expandoDic.Keys.ToList();
            }
            return GetPropertyInfos(obj).Select(x => x.Name).ToList();
        }

        private static List<PropertyInfo> GetPropertyInfos(object obj)
        {
            if (obj == null)
            {
                return new List<PropertyInfo>();
            }
            List<PropertyInfo> properties;
            if (_paramCache.TryGetValue(obj.GetType(), out properties)) return properties.ToList();
            properties = obj.GetType().GetProperties(BindingFlags.GetProperty | BindingFlags.Instance | BindingFlags.Public).ToList();
            _paramCache[obj.GetType()] = properties;
            return properties;
        }
    }
}