DataProvider不等于SQLHelper

微软企业库可用来做ORM，其数据层核心是DataProvider，类似常用的SQLHelper，但这仅仅只是类似而已。以下是其反编后的代码：

public class DataProvider
{
public string ConnectionString = string.Empty;
private SqlConnection DbConnection = null;
private SqlCommand DbCommand = null;
private SqlTransaction DbTransaction = null;
[MethodImpl(MethodImplOptions.NoInlining)]
private void Open()
{
if (this.DbConnection == null)
{
this.DbConnection = new SqlConnection(this.ConnectionString);
}
if (!this.DbConnection.State.Equals(ConnectionState.Open))
{
this.DbConnection.Open();
}
}
[MethodImpl(MethodImplOptions.NoInlining)]
public void Close()
{
if (this.DbConnection != null)
{
if (this.DbConnection.State.Equals(ConnectionState.Open))
{
this.Rollback();
this.DbConnection.Close();
}
if (this.DbCommand != null)
{
this.DbCommand.Dispose();
this.DbCommand = null;
}
this.DbConnection.Dispose();
this.DbConnection = null;
}
}
private void CreateCommand()
{
this.Open();
if (this.DbCommand == null)
{
this.DbCommand = this.DbConnection.CreateCommand();
this.DbCommand.CommandTimeout = 180;
}
}
[MethodImpl(MethodImplOptions.NoInlining)]
public void BeginTransaction()
{
this.CreateCommand();
this.DbTransaction = this.DbConnection.BeginTransaction();
this.DbCommand.Transaction = this.DbTransaction;
}
[MethodImpl(MethodImplOptions.NoInlining)]
public void Commit()
{
if (this.DbTransaction != null)
{
this.DbTransaction.Commit();
this.DbTransaction.Dispose();
this.DbTransaction = null;
}
}
[MethodImpl(MethodImplOptions.NoInlining)]
public void Rollback()
{
if (this.DbTransaction != null)
{
this.DbTransaction.Rollback();
this.DbTransaction.Dispose();
this.DbTransaction = null;
}
}
public int ExecuteNonQuery(string SQL, CommandType type)
{
this.CreateCommand();
this.DbCommand.CommandText = SQL;
this.DbCommand.CommandType = type;
return this.DbCommand.ExecuteNonQuery();
}
[MethodImpl(MethodImplOptions.NoInlining)]
public DataSet ExecuteDataSet(string SQL, CommandType type)
{
SqlDataAdapter sqlDataAdapter = new SqlDataAdapter();
DataSet result;
try
{
this.CreateCommand();
this.DbCommand.CommandText = SQL;
this.DbCommand.CommandType = type;
sqlDataAdapter = new SqlDataAdapter(this.DbCommand);
DataSet dataSet = new DataSet();
sqlDataAdapter.Fill(dataSet);
result = dataSet;
}
catch (Exception ex)
{
throw ex;
}
finally
{
if (sqlDataAdapter != null)
{
sqlDataAdapter.Dispose();
}
}
return result;
}
[MethodImpl(MethodImplOptions.NoInlining)]
public DataTable ExecutedProcedure(string strProcedureName, SqlParameter[] parameters)
{
SqlDataAdapter sqlDataAdapter = new SqlDataAdapter();
DataTable result;
try
{
this.CreateCommand();
this.DbCommand.CommandText = strProcedureName;
this.DbCommand.CommandType = CommandType.StoredProcedure;
if (parameters != null)
{
for (int i = 0; i < parameters.Length; i++)
{
this.DbCommand.Parameters.Add(parameters[i]);
}
}
sqlDataAdapter = new SqlDataAdapter(this.DbCommand);
DataSet dataSet = new DataSet();
sqlDataAdapter.Fill(dataSet);
result = dataSet.Tables[0];
}
catch (Exception ex)
{
throw ex;
}
finally
{
if (sqlDataAdapter != null)
{
sqlDataAdapter.Dispose();
}
}
return result;
}
[MethodImpl(MethodImplOptions.NoInlining)]
public DataTable ExecuteDataTable(string SQL, CommandType type)
{
DataSet dataSet = this.ExecuteDataSet(SQL, type);
DataTable result;
if (dataSet == null || dataSet.Tables.Count <= 0)
{
result = null;
}
else
{
result = dataSet.Tables[0];
}
return result;
}
[MethodImpl(MethodImplOptions.NoInlining)]
public string ExecuteScalar(string sql, CommandType type, SqlParameter[] parameters)
{
string result = string.Empty;
try
{
this.CreateCommand();
this.DbCommand.CommandText = sql;
this.DbCommand.CommandType = type;
if (parameters != null)
{
for (int i = 0; i < parameters.Length; i++)
{
this.DbCommand.Parameters.Add(parameters[i]);
}
}
object obj = this.DbCommand.ExecuteScalar();
if (obj != null)
{
result = obj.ToString();
}
}
catch (Exception ex)
{
string message = ex.Message;
}
return result;
}
}

所有的执行方法都是只有打开执行，没有用using，也没有在方法体内关闭连接，那么问题来了，如果像sqlhelper一样的调用它的话，那么数据库将会建立很多连接，一直到你的限制数（webconfig中设置的Max Pool Size=200），然后异常。

可以通过sql性能工具看到当前的ExistingConnection，如果不关闭，每一次刷新，都会多几个连接。

关于ExistingConnection，msdn

另一个可以通过Windows的性能计数器看到，执行一次业务数据，线陡然上升一次。。。。



当然连接最终是可以回收的，但需要时间很长。

由于数据层用了企业库，而又确实要调用这个类，目前想到以下两种方法：

1、所有的CRUD都要记得显式关闭连接。
2、可以封装一个单例模式或者写成静态类，所有的业务层都要调用同一个类的方法。