强大的数据库访问类dbhelper 2.0 转
优点：
1、多数据库支持
2、多数据库类型支持
3、强大的查询公用方法，如支持返回泛型实体对象集合，泛型值类型集合，实体对象，数据集等。
4、所有方法都支持参数化与非参数化访问db，调用十分方便。
5、使用了线程本地存储，使之能支持在业务逻辑层显式控制事务。
6、注释较为详细，配置十分简单，方法较为简洁(加上注释总共200多行代码)。
7、开源，容易修改。
源代码：DBManager
public class DBManager
{
/// <summary>
/// 默认的数据库连接
/// </summary>
public static readonly string connectionString = ConfigurationManager.AppSettings["ConnectionString"];
/// <summary>
/// 数据库类型 默认支持sqlserver数据库
/// </summary>
public static readonly string dbProviderName = string.IsNullOrEmpty(ConfigurationManager.AppSettings["dbProviderName"])
? "System.Data.SqlClient" : ConfigurationManager.AppSettings["dbProviderName"];
[ThreadStatic]
static DBHelper helper;
/// <summary>
/// 创建默认的数据库访问类
/// </summary>
/// <returns></returns>
public static DBHelper Instance()
{
if (helper == null)
{
helper = new DBHelper(connectionString, dbProviderName);
return helper;
}
return helper;
}
}
DBHelper:
public class DBHelper
{
private string connectionString = string.Empty;
private DbProviderFactory factory;
private DbConnection _connection;
public DbConnection connection
{
get { return _connection; }
set { _connection = value; }
}
private DbTransaction _transaction;
public DbTransaction transaction
{
get { return _transaction; }
set { _transaction = value; ;}
}
public DBHelper(string connectionString, string dbProviderName)
{
this.connectionString = connectionString;
factory = DbProviderFactories.GetFactory(dbProviderName);
}
/// <summary>
/// 打开数据库连接
/// </summary>
public void OpenConnection()
{
if (connection == null)
{
connection = factory.CreateConnection();
connection.ConnectionString = connectionString;
}
if (connection.State != ConnectionState.Open)
connection.Open();
}
/// <summary>
/// 开启事务
/// </summary>
public void BeginTransaction()
{
OpenConnection();
if (transaction == null)
transaction = connection.BeginTransaction();
}
/// <summary>
/// 提交事务 并且 释放并关闭资源
/// </summary>
public void CommitTransaction()
{
if (transaction != null)
{
transaction.Commit();
transaction.Dispose();
transaction = null;
Dispose();
}
}
/// <summary>
/// 回滚事务 并且 释放并关闭资源
/// </summary>
public void RollbackTransaction()
{
if (transaction != null)
{
transaction.Rollback();
transaction.Dispose();
transaction = null;
Dispose();
}
}
/// <summary>
/// 如果没有开启事务就自动释放资源，关闭连接，否则在提交或回滚事务的时候释放
/// </summary>
public void Dispose()
{
if (transaction == null)
{
if (connection != null)
{
connection.Dispose();
connection.Close();
connection = null;
}
}
}
private DbCommand CreateCommand(CommandType cmdType, string cmdText, params DbParameter[] cmdParas)
{
DbCommand mand = connection.CreateCommand();
mand.CommandText = cmdText;
mand.CommandType = cmdType;
mand.Parameters.AddRange(cmdParas);
if (transaction != null) mand.Transaction = transaction;
return mand;
}
/// <summary>
/// 返回一个数据集
/// </summary>
/// <param name="cmdType"></param>
/// <param name="cmdText"></param>
/// <param name="cmdParas"></param>
/// <returns></returns>
public DataSet ExecuteDataSet(CommandType cmdType, string cmdText, params DbParameter[] cmdParas)
{
try
{
OpenConnection();
DbCommand mand = CreateCommand(cmdType, cmdText, cmdParas);
DbDataAdapter data = factory.CreateDataAdapter();
DataSet ds = new DataSet();
data.Fill(ds);
return ds;
}
catch (Exception ex) { throw ex; }
finally { Dispose(); }
}
/// <summary>
/// 返回受影响的行数
/// </summary>
/// <param name="cmdType"></param>
/// <param name="cmdText"></param>
/// <param name="cmdParas"></param>
/// <returns></returns>
public int ExecuteNonQuery(CommandType cmdType, string cmdText, params DbParameter[] cmdParas)
{
try
{
OpenConnection();
DbCommand mand = CreateCommand(cmdType, cmdText, cmdParas);
return mand.ExecuteNonQuery();
}
catch (Exception ex) { throw ex; }
finally { Dispose(); }
}
/// <summary>
/// 返回结果集中第一行第一列
/// </summary>
/// <param name="cmdType"></param>
/// <param name="cmdText"></param>
/// <param name="cmdParas"></param>
/// <returns></returns>
public object ExecuteScalar(CommandType cmdType, string cmdText, params DbParameter[] cmdParas)
{
try
{
OpenConnection();
DbCommand mand = CreateCommand(cmdType, cmdText, cmdParas);
return mand.ExecuteScalar();
}
catch (Exception ex) { throw ex; }
finally { Dispose(); }
}
/// <summary>
/// 返回泛型集合
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="cmdType"></param>
/// <param name="cmdText"></param>
/// <param name="cmdParas"></param>
/// <returns></returns>
public IList<T> ExecuteReaderList<T>(CommandType cmdType, string cmdText, params DbParameter[] cmdParas)
{
try
{
OpenConnection();
DbCommand mand = CreateCommand(cmdType, cmdText, cmdParas);
DbDataReader reader = mand.ExecuteReader();
IList<T> list = ToList<T>(reader);
return list;
}
catch (Exception ex) { throw ex; }
finally { Dispose(); }
}
/// <summary>
/// 返回一个对象 如数据库无结果返回将抛出异常
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="cmdType"></param>
/// <param name="cmdText"></param>
/// <param name="cmdParas"></param>
/// <returns></returns>
public T ExecuteReaderObject<T>(CommandType cmdType, string cmdText, params DbParameter[] cmdParas)
{
return ExecuteReaderList<T>(cmdType, cmdText, cmdParas)[0];
}
/// <summary>
/// 反射创建泛型集合
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="reader"></param>
/// <returns></returns>
private IList<T> ToList<T>(DbDataReader reader)
{
Type type = typeof(T);
IList<T> list = null;
if (type.IsValueType || type == typeof(string))
list = CreateValue<T>(reader, type);
else
list = CreateObject<T>(reader, type);
reader.Dispose();
reader.Close();
return list;
}
private IList<T> CreateObject<T>(DbDataReader reader, Type type)
{
IList<T> list = new List<T>();
PropertyInfo[] properties = type.GetProperties();
string name = string.Empty;
while (reader.Read())
{
T local = Activator.CreateInstance<T>();
for (int i = 0; i < reader.FieldCount; i++)
{
name = reader.GetName(i);
foreach (PropertyInfo info in properties)
{
if (name.Equals(info.Name))
info.SetValue(local, Convert.ChangeType(reader[info.Name], info.PropertyType), null); break;
}
}
list.Add(local);
}
return list;
}
private IList<T> CreateValue<T>(DbDataReader reader, Type type)
{
IList<T> list = new List<T>();
while (reader.Read())
{
T local = (T)Convert.ChangeType(reader[0], type, null);
list.Add(local);
}
return list;
}
}
调用示例：
/// <summary>
/// 事务示例
/// </summary>
public void TestExecuteNonQueryBeginTran()
{
try
{
DBManager.Instance().BeginTransaction();
DBManager.Instance().ExecuteNonQuery(CommandType.Text, "update warningTest set pid=0 where id=3");
DBManager.Instance().ExecuteNonQuery(CommandType.Text, "update warningTest set pid=aaa where id=4");
DBManager.Instance().CommitTransaction();
int num = DBManager.Instance().ExecuteNonQuery(System.Data.CommandType.Text, "select * from warningTest");
}
catch { DBManager.Instance().RollbackTransaction(); }
}
/// <summary>
/// 查询实体对象集合示例
/// </summary>
public void TestExecuteReaderList()
{
SqlParameter para = new SqlParameter("@id", 1);
warningTest warning = DBManager.Instance().ExecuteReaderObject<warningTest>(CommandType.Text, "select * from warningTest where id=@id", para);
Assert.AreEqual(1, warning.id);
}
/// <summary>
/// 查询值类型集合示例
/// </summary>
public void TestExecuteReaderListByInt()
{
IList<string> list = DBManager.Instance().ExecuteReaderList<string>(CommandType.Text, "select Logic from warningTest");
foreach (string i in list)
{
Console.WriteLine(i.ToString());
}
}
下载：源代码
补充说明：数据库备份文件在Data.test\App_Data文件夹下面