一步一步打造3层架构在线电影网站!(3)系统设计

王朝other·作者佚名  2006-01-09
窄屏简体版  字體: |||超大  

前面讨论了数据库部分地设计和实现,现在开始真正的用C#编码了。

这里我都是将设计和实现结合在一起写的,从层次结构上来说应该更加清晰吧。

4、 核心代码设计核心代码主要是封装一些公用的功能,以后的数据层,商务层代码会继承核心代码,并且统一利用核心代码所提供的功能。核心代码类是抽象类,不可以实例化得。

Coofucoo.Core.DbObject:此类是所有数据层类得基类

using System;

using System.Data;

using System.Data.SqlClient;

namespace Coofucoo.Core

{

/// <summary>

/// DbObject is the class from which all classes in the Data Services

/// Tier inherit. The core functionality of establishing a connection

/// with the database and executing simple stored procedures is also

/// provided by this base class.

/// </summary>

public abstract class DbObject

{

protected SqlConnection Connection;

private string connectionString;

/// <summary>

/// A parameterized constructor, it allows us to take a connection

/// string as a constructor argument, automatically instantiating

/// a new connection.

/// </summary>

/// <param name="newConnectionString">Connection String to the associated database</param>

public DbObject( string newConnectionString )

{

connectionString = newConnectionString;

Connection = new SqlConnection( connectionString );

}

/// <summary>

/// Protected property that exposes the connection string

/// to inheriting classes. Read-Only.

/// </summary>

protected string ConnectionString

{

get

{

return connectionString;

}

}

/// <summary>

/// Private routine allowed only by this base class, it automates the task

/// of building a SqlCommand object designed to obtain a return value from

/// the stored procedure.

/// </summary>

/// <param name="storedProcName">Name of the stored procedure in the DB, eg. sp_DoTask</param>

/// <param name="parameters">Array of IDataParameter objects containing parameters to the stored proc</param>

/// <returns>Newly instantiated SqlCommand instance</returns>

private SqlCommand BuildIntCommand(string storedProcName, IDataParameter[] parameters)

{

SqlCommand command = BuildQueryCommand( storedProcName, parameters );

command.Parameters.Add( new SqlParameter ( "ReturnValue",

SqlDbType.Int,

4, /* Size */

ParameterDirection.ReturnValue,

false, /* is nullable */

0, /* byte precision */

0, /* byte scale */

string.Empty,

DataRowVersion.Default,

null ));

return command;

}

/// <summary>

/// Builds a SqlCommand designed to return a SqlDataReader, and not

/// an actual integer value.

/// </summary>

/// <param name="storedProcName">Name of the stored procedure</param>

/// <param name="parameters">Array of IDataParameter objects</param>

/// <returns></returns>

private SqlCommand BuildQueryCommand(string storedProcName, IDataParameter[] parameters)

{

SqlCommand command = new SqlCommand( storedProcName, Connection );

command.CommandType = CommandType.StoredProcedure;

foreach (SqlParameter parameter in parameters)

{

command.Parameters.Add( parameter );

}

return command;

}

/// <summary>

/// Runs a stored procedure, can only be called by those classes deriving

/// from this base. It returns an integer indicating the return value of the

/// stored procedure, and also returns the value of the RowsAffected aspect

/// of the stored procedure that is returned by the ExecuteNonQuery method.

/// </summary>

/// <param name="storedProcName">Name of the stored procedure</param>

/// <param name="parameters">Array of IDataParameter objects</param>

/// <param name="rowsAffected">Number of rows affected by the stored procedure.</param>

/// <returns>An integer indicating return value of the stored procedure</returns>

protected int RunProcedure(string storedProcName, IDataParameter[] parameters, out int rowsAffected )

{

int result;

Connection.Open();

SqlCommand command = BuildIntCommand( storedProcName, parameters );

rowsAffected = command.ExecuteNonQuery();

result = (int)command.Parameters["ReturnValue"].Value;

Connection.Close();

return result;

}

/// <summary>

/// Will run a stored procedure, can only be called by those classes deriving

/// from this base. It returns a SqlDataReader containing the result of the stored

/// procedure.

/// </summary>

/// <param name="storedProcName">Name of the stored procedure</param>

/// <param name="parameters">Array of parameters to be passed to the procedure</param>

/// <returns>A newly instantiated SqlDataReader object</returns>

protected SqlDataReader RunProcedure(string storedProcName, IDataParameter[] parameters )

{

SqlDataReader returnReader;

Connection.Open();

SqlCommand command = BuildQueryCommand( storedProcName, parameters );

command.CommandType = CommandType.StoredProcedure;

returnReader = command.ExecuteReader();

//Connection.Close();

return returnReader;

}

/// <summary>

/// Creates a DataSet by running the stored procedure and placing the results

/// of the query/proc into the given tablename.

/// </summary>

/// <param name="storedProcName"></param>

/// <param name="parameters"></param>

/// <param name="tableName"></param>

/// <returns></returns>

protected DataSet RunProcedure(string storedProcName, IDataParameter[] parameters, string tableName )

{

DataSet dataSet = new DataSet();

Connection.Open();

SqlDataAdapter sqlDA = new SqlDataAdapter();

sqlDA.SelectCommand = BuildQueryCommand( storedProcName, parameters );

sqlDA.Fill( dataSet, tableName );

Connection.Close();

return dataSet;

}

/// <summary>

/// Takes an -existing- dataset and fills the given table name with the results

/// of the stored procedure.

/// </summary>

/// <param name="storedProcName"></param>

/// <param name="parameters"></param>

/// <param name="dataSet"></param>

/// <param name="tableName"></param>

/// <returns></returns>

protected void RunProcedure(string storedProcName, IDataParameter[] parameters, DataSet dataSet, string tableName )

{

Connection.Open();

SqlDataAdapter sqlDA = new SqlDataAdapter();

sqlDA.SelectCommand = BuildIntCommand( storedProcName, parameters );

sqlDA.Fill( dataSet, tableName );

Connection.Close();

}

}

}

Coofucoo.Core.BizObject:商务层类得基类,无任何内容,以后可以添加。

using System;

namespace Coofucoo.Core

{

/// <summary>

/// The class from which all classes in the business tier

/// inherit from.

/// </summary>

public class BizObject

{

public BizObject()

{

}

}

}

 
 
 
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