一：优势
1，Dapper是一个轻型的ORM类。代码就一个SqlMapper.cs文件，编译后就40K的一个很小的Dll.
2，Dapper很快。Dapper的速度接近与IDataReader，取列表的数据超过了DataTable。
3，Dapper支持什么数据库。Dapper支持Mysql,SqlLite,Mssql2000,Mssql2005,Oracle等一系列的数据库，当然如果你知道原理也可以让它支持Mongo db
4，Dapper的r支持多表并联的对象。支持一对多 多对多的关系。并且没侵入性，想用就用，不想用就不用。无XML无属性。代码以前怎么写现在还怎么写。 5，Dapper原理通过Emit反射IDataReader的序列队列，来快速的得到和产生对象。性能实在高高高。
6，Dapper支持net2.0,3.0,3.5,4.0。【如果想在Net2.0下使用，可以去网上找一下Net2.0下如何配置运行Net3.5即可。】 7，Dapper语法十分简单。并且无须迁就数据库的设计。
二：ASP .Net Core 中使用dapper可以很方便的操作mysql数据
需要安装如下类库
"Dapper": "1.50.2",
"NETStandard.Library": "1.6.0",
"SapientGuardian.MySql.Data": "6.9.813"
三：基于dapper的操作mysql的封装类
/// <summary>
///作者： 逍遥帝君
/// 2016-10-26
/// </summary>
public class DapperMySQLHelp
{
#region +ExcuteNonQuery 增、删、改同步操作
/// <summary>
/// 增、删、改同步操作
/// 作者： 逍遥帝君
/// 2016-10-26
/// </summary>
/// <typeparam name="T">实体</typeparam>
/// <param name="connection">链接字符串</param>
/// <param name="cmd">sql语句</param>
/// <param name="param">参数</param>
/// <param name="flag">true存储过程，false sql语句</param>
/// <returns>int</returns>
public int ExcuteNonQuery<T>(string connection, string cmd, DynamicParameters param, bool flag = true) where T : class, new()
{
int result = 0;
using (MySqlConnection con = new MySqlConnection(connection))
{
if (flag)
{
result = con.Execute(cmd, param, null, null, CommandType.StoredProcedure);
}
else
{
result = con.Execute(cmd, param, null, null, CommandType.Text);
}
}
return result;
}
#endregion
#region +ExcuteNonQueryAsync 增、删、改异步操作
/// <summary>
/// 增、删、改异步操作
/// 作者： 逍遥帝君
/// 2016-10-26
/// </summary>
/// <typeparam name="T">实体</typeparam>
/// <param name="connection">链接字符串</param>
/// <param name="cmd">sql语句</param>
/// <param name="param">参数</param>
/// <param name="flag">true存储过程，false sql语句</param>
/// <returns>int</returns>
public async Task<int> ExcuteNonQueryAsync<T>(string connection, string cmd, DynamicParameters param, bool flag = true) where T : class, new()
{
int result = 0;
using (MySqlConnection con = new MySqlConnection(connection))
{
if (flag)
{
result = await con.ExecuteAsync(cmd, param, null, null, CommandType.StoredProcedure);
}
else
{
result = await con.ExecuteAsync(cmd, param, null, null, CommandType.Text);
}
}
return result;
}
#endregion
#region +ExecuteScalar 同步查询操作
/// <summary>
/// 同步查询操作
/// 作者： 逍遥帝君
/// 2016-10-26
/// </summary>
/// <typeparam name="T">实体</typeparam>
/// <param name="connection">连接字符串</param>
/// <param name="cmd">sql语句</param>
/// <param name="param">参数</param>
/// <param name="flag">true存储过程，false sql语句</param>
/// <returns>object</returns>
public object ExecuteScalar<T>(string connection, string cmd, DynamicParameters param, bool flag = true) where T : class, new()
{
object result = null;
using (MySqlConnection con = new MySqlConnection(connection))
{
if (flag)
{
result = con.ExecuteScalar(cmd, param, null, null, CommandType.StoredProcedure);
}
else
{
result = con.ExecuteScalar(cmd, param, null, null, CommandType.Text);
}
}
return result;
}
#endregion
#region +ExecuteScalarAsync 异步查询操作
/// <summary>
/// 异步查询操作
/// 作者： 逍遥帝君
/// 2016-10-26
/// </summary>
/// <typeparam name="T">实体</typeparam>
/// <param name="connection">连接字符串</param>
/// <param name="cmd">sql语句</param>
/// <param name="param">参数</param>
/// <param name="flag">true存储过程，false sql语句</param>
/// <returns>object</returns>
public async Task<object> ExecuteScalarAsync<T>(string connection, string cmd, DynamicParameters param, bool flag = true) where T : class, new()
{
object result = null;
using (MySqlConnection con = new MySqlConnection(connection))
{
if (flag)
{
result = await con.ExecuteScalarAsync(cmd, param, null, null, CommandType.StoredProcedure);
}
else
{
result = con.ExecuteScalarAsync(cmd, param, null, null, CommandType.Text);
}
}
return result;
}
#endregion
#region +FindOne 同步查询一条数据
/// <summary>
/// 同步查询一条数据
/// 作者： 逍遥帝君
/// 2016-10-26
/// </summary>
/// <typeparam name="T">实体</typeparam>
/// <param name="connection">连接字符串</param>
/// <param name="cmd">sql语句</param>
/// <param name="param">参数</param>
/// <param name="flag">true存储过程，false sql语句</param>
/// <returns>t</returns>
public T FindOne<T>(string connection, string cmd, DynamicParameters param, bool flag = true) where T : class, new()
{
IDataReader dataReader = null;
using (MySqlConnection con = new MySqlConnection(connection))
{
if (flag)
{
dataReader = con.ExecuteReader(cmd, param, null, null, CommandType.StoredProcedure);
}
else
{
dataReader = con.ExecuteReader(cmd, param, null, null, CommandType.Text);
}
if (dataReader == null || !dataReader.Read()) return null;
Type type = typeof(T);
T t = new T();
foreach (var item in type.GetProperties())
{
for (int i = 0; i < dataReader.FieldCount; i++)
{
//属性名与查询出来的列名比较
if (item.Name.ToLower() != dataReader.GetName(i).ToLower()) continue;
var kvalue = dataReader[item.Name];
if (kvalue == DBNull.Value) continue;
item.SetValue(t, kvalue, null);
break;
}
}
return t;
}
}
#endregion
#region +FindOne 异步查询一条数据
/// <summary>
/// 异步查询一条数据
/// 作者： 逍遥帝君
/// 2016-10-26
/// </summary>
/// <typeparam name="T">实体</typeparam>
/// <param name="connection">连接字符串</param>
/// <param name="cmd">sql语句</param>
/// <param name="param">参数</param>
/// <param name="flag">true存储过程，false sql语句</param>
/// <returns>t</returns>
public async Task<T> FindOneAsync<T>(string connection, string cmd, DynamicParameters param, bool flag = true) where T : class, new()
{
IDataReader dataReader = null;
using (MySqlConnection con = new MySqlConnection(connection))
{
if (flag)
{
dataReader = await con.ExecuteReaderAsync(cmd, param, null, null, CommandType.StoredProcedure);
}
else
{
dataReader = await con.ExecuteReaderAsync(cmd, param, null, null, CommandType.Text);
}
if (dataReader == null || !dataReader.Read()) return null;
Type type = typeof(T);
T t = new T();
foreach (var item in type.GetProperties())
{
for (int i = 0; i < dataReader.FieldCount; i++)
{
//属性名与查询出来的列名比较
if (item.Name.ToLower() != dataReader.GetName(i).ToLower()) continue;
var kvalue = dataReader[item.Name];
if (kvalue == DBNull.Value) continue;
item.SetValue(t, kvalue, null);
break;
}
}
return t;
}
}
#endregion
#region +FindToList 同步查询数据集合
/// <summary>
/// 同步查询数据集合
/// 作者： 逍遥帝君
/// 2016-10-26
/// </summary>
/// <typeparam name="T">实体</typeparam>
/// <param name="connection">连接字符串</param>
/// <param name="cmd">sql语句</param>
/// <param name="param">参数</param>
/// <param name="flag">true存储过程，false sql语句</param>
/// <returns>t</returns>
public IList<T> FindToList<T>(string connection, string cmd, DynamicParameters param, bool flag = true) where T : class, new()
{
IDataReader dataReader = null;
using (MySqlConnection con = new MySqlConnection(connection))
{
if (flag)
{
dataReader = con.ExecuteReader(cmd, param, null, null, CommandType.StoredProcedure);
}
else
{
dataReader = con.ExecuteReader(cmd, param, null, null, CommandType.Text);
}
if (dataReader == null || !dataReader.Read()) return null;
Type type = typeof(T);
List<T> tlist = new List<T>();
while (dataReader.Read())
{
T t = new T();
foreach (var item in type.GetProperties())
{
for (int i = 0; i < dataReader.FieldCount; i++)
{
//属性名与查询出来的列名比较
if (item.Name.ToLower() != dataReader.GetName(i).ToLower()) continue;
var kvalue = dataReader[item.Name];
if (kvalue == DBNull.Value) continue;
item.SetValue(t, kvalue, null);
break;
}
}
if (tlist != null) tlist.Add(t);
}
return tlist;
}
}
#endregion
#region +FindToListAsync 异步查询数据集合
/// <summary>
/// 异步查询数据集合
/// 作者： 逍遥帝君
/// 2016-10-26
/// </summary>
/// <typeparam name="T">实体</typeparam>
/// <param name="connection">连接字符串</param>
/// <param name="cmd">sql语句</param>
/// <param name="param">参数</param>
/// <param name="flag">true存储过程，false sql语句</param>
/// <returns>t</returns>
public async Task<IList<T>> FindToListAsync<T>(string connection, string cmd, DynamicParameters param, bool flag = true) where T : class, new()
{
IDataReader dataReader = null;
using (MySqlConnection con = new MySqlConnection(connection))
{
if (flag)
{
dataReader = await con.ExecuteReaderAsync(cmd, param, null, null, CommandType.StoredProcedure);
}
else
{
dataReader = await con.ExecuteReaderAsync(cmd, param, null, null, CommandType.Text);
}
if (dataReader == null || !dataReader.Read()) return null;
Type type = typeof(T);
List<T> tlist = new List<T>();
while (dataReader.Read())
{
T t = new T();
foreach (var item in type.GetProperties())
{
for (int i = 0; i < dataReader.FieldCount; i++)
{
//属性名与查询出来的列名比较
if (item.Name.ToLower() != dataReader.GetName(i).ToLower()) continue;
var kvalue = dataReader[item.Name];
if (kvalue == DBNull.Value) continue;
item.SetValue(t, kvalue, null);
break;
}
}
if (tlist != null) tlist.Add(t);
}
return tlist;
}
}
#endregion
#region +FindToList 同步查询数据集合
/// <summary>
/// 同步查询数据集合
/// 作者： 逍遥帝君
/// 2016-10-26
/// </summary>
/// <typeparam name="T">实体</typeparam>
/// <param name="connection">连接字符串</param>
/// <param name="cmd">sql语句</param>
/// <param name="param">参数</param>
/// <param name="flag">true存储过程，false sql语句</param>
/// <returns>t</returns>
public IList<T> FindToListAsPage<T>(string connection, string cmd, DynamicParameters param, bool flag = true) where T : class, new()
{
IDataReader dataReader = null;
using (MySqlConnection con = new MySqlConnection(connection))
{
if (flag)
{
dataReader = con.ExecuteReader(cmd, param, null, null, CommandType.StoredProcedure);
}
else
{
dataReader = con.ExecuteReader(cmd, param, null, null, CommandType.Text);
}
if (dataReader == null || !dataReader.Read()) return null;
Type type = typeof(T);
List<T> tlist = new List<T>();
while (dataReader.Read())
{
T t = new T();
foreach (var item in type.GetProperties())
{
for (int i = 0; i < dataReader.FieldCount; i++)
{
//属性名与查询出来的列名比较
if (item.Name.ToLower() != dataReader.GetName(i).ToLower()) continue;
var kvalue = dataReader[item.Name];
if (kvalue == DBNull.Value) continue;
item.SetValue(t, kvalue, null);
break;
}
}
if (tlist != null) tlist.Add(t);
}
return tlist;
}
}
#endregion
#region +FindToListByPage 同步分页查询数据集合
/// <summary>
/// 同步分页查询数据集合
/// 作者： 逍遥帝君
/// 2016-10-26
/// </summary>
/// <typeparam name="T">实体</typeparam>
/// <param name="connection">连接字符串</param>
/// <param name="cmd">sql语句</param>
/// <param name="param">参数</param>
/// <param name="flag">true存储过程，false sql语句</param>
/// <returns>t</returns>
public IList<T> FindToListByPage<T>(string connection, string cmd, DynamicParameters param, bool flag = true) where T : class, new()
{
IDataReader dataReader = null;
using (MySqlConnection con = new MySqlConnection(connection))
{
if (flag)
{
dataReader = con.ExecuteReader(cmd, param, null, null, CommandType.StoredProcedure);
}
else
{
dataReader = con.ExecuteReader(cmd, param, null, null, CommandType.Text);
}
if (dataReader == null || !dataReader.Read()) return null;
Type type = typeof(T);
List<T> tlist = new List<T>();
while (dataReader.Read())
{
T t = new T();
foreach (var item in type.GetProperties())
{
for (int i = 0; i < dataReader.FieldCount; i++)
{
//属性名与查询出来的列名比较
if (item.Name.ToLower() != dataReader.GetName(i).ToLower()) continue;
var kvalue = dataReader[item.Name];
if (kvalue == DBNull.Value) continue;
item.SetValue(t, kvalue, null);
break;
}
}
if (tlist != null) tlist.Add(t);
}
return tlist;
}
}
#endregion
#region +FindToListByPageAsync 异步分页查询数据集合
/// <summary>
/// 异步分页查询数据集合
/// 作者： 逍遥帝君
/// 2016-10-26
/// </summary>
/// <typeparam name="T">实体</typeparam>
/// <param name="connection">连接字符串</param>
/// <param name="cmd">sql语句</param>
/// <param name="param">参数</param>
/// <param name="flag">true存储过程，false sql语句</param>
/// <returns>t</returns>
public async Task<IList<T>> FindToListByPageAsync<T>(string connection, string cmd, DynamicParameters param, bool flag = true) where T : class, new()
{
IDataReader dataReader = null;
using (MySqlConnection con = new MySqlConnection(connection))
{
if (flag)
{
dataReader = await con.ExecuteReaderAsync(cmd, param, null, null, CommandType.StoredProcedure);
}
else
{
dataReader = await con.ExecuteReaderAsync(cmd, param, null, null, CommandType.Text);
}
if (dataReader == null || !dataReader.Read()) return null;
Type type = typeof(T);
List<T> tlist = new List<T>();
while (dataReader.Read())
{
T t = new T();
foreach (var item in type.GetProperties())
{
for (int i = 0; i < dataReader.FieldCount; i++)
{
//属性名与查询出来的列名比较
if (item.Name.ToLower() != dataReader.GetName(i).ToLower()) continue;
var kvalue = dataReader[item.Name];
if (kvalue == DBNull.Value) continue;
item.SetValue(t, kvalue, null);
break;
}
}
if (tlist != null) tlist.Add(t);
}
return tlist;
}
}
#endregion
}
四：分页查询存储过程
存储过程
CREATE PROCEDURE page_getperson
（
_pageIndex INT,
_pageSize INT,
out _pagecount int
）
BEGIN
DECLARE startIndex int DEFAULT 0;
DECLARE tcount int DEFAULT 0;
set startIndex=(_pageIndex-1)*_pageSize;
SELECT * from Person LIMIT startIndex,_pageSize;
SELECT COUNT(id) into tcount from Person;
set _pagecount=tcount;
END
五：参数写法
DynamicParameters param = new DynamicParameters();
param.Add("_pageIndex", 2);
param.Add("_pageSize", 5);
param.Add("_pagecount", dbType: DbType.Int32, direction: ParameterDirection.Output);
var result = mysql.FindToListByPage<Person>(connection, "page_getperson", param);
//总条数
var count = param.Get<int>("_pagecount");
var kk = result;
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