Question

我是3层架构的新手，下面是我的DAL代码

public static int Insert(string firstname, string lastname, DateTime dob, string gender,string email, string password)
    {
        // bool flag = false;
        SqlParameter pid;
        SqlParameter result;

        SqlConnection con = Generic.DBConnection.OpenConnection();

        try
        {

            SqlCommand cmd1 = new SqlCommand("Insertreg", con);
            cmd1.CommandType = CommandType.StoredProcedure;
            cmd1.Parameters.AddWithValue("@FirstName", firstname);
            cmd1.Parameters.AddWithValue("@LastName", lastname);
            cmd1.Parameters.AddWithValue("@Dob", dob);
            cmd1.Parameters.AddWithValue("@Gender", gender);
           cmd1.Parameters.AddWithValue("@EmailId", email);
            cmd1.Parameters.AddWithValue("@Password", password);
            result = cmd1.Parameters.Add("@result", System.Data.SqlDbType.Int);
            result.Direction = System.Data.ParameterDirection.Output;
            pid = cmd1.Parameters.Add("@id", System.Data.SqlDbType.Int);
            pid.Direction = System.Data.ParameterDirection.Output;
            return cmd1.ExecuteNonQuery();


            con.Close();

        }
        catch (Exception ex)
        {
            throw ex;
        }
    }

这在BAL

 public int insert(string firstname,string lastname,DateTime dob,string gender,string email,string password)
    {
      ProfileMasterDAL dal=new ProfileMasterDAL();
      try
      {
          return ProfileMasterDAL.Insert(firstname, lastname, dob, gender,email, password);
      }
      catch (Exception ex)
      {

          throw ex;
      }
        finally
      {
          dal = null;
      }

    }

我是我的用户界面

  ProfileMasterBLL pmBLL = new ProfileMasterBLL();
 pmBLL.insert(firstname, lastname, dob, gender, mobile, country, state, email, password);

这是在3层中编码的正确方法吗？我的意思是如何将方法从DAL调用到BAL并进入UI？如果没有建议我一些好方法。谢谢。

Answer 1

通常我会做以下事情：

定义业务层（BL，您将其称为BAL）。这包含您的业务实体的定义。它还定义了用于检索/保存/删除您使用的任何模式（存储库，上下文等）的数据的接口。
定义数据访问层（DAL）。这包含了检索/保存/删除接口的实际实现。
定义UI图层。这包含UI元素（表单，控件，模型，控制器等），它们可以使用BL来加载数据。

参考文献如下：

BL不知道DAL或UI。
DAL知道BL。 DAL不知道用户界面。
UI知道BL。用户界面不知道DAL。

对你来说最大的问题是，当BL不知道DAL时，BL如何检索/保存/删除数据，因此无法在DAL中创建类的实例。嗯，这是一个小Dependency Injection派上用场的地方。你需要连接的就是将DAL类注入BL接口。

希望这是有道理的。我将它用作我的标准3层实现，它绝对没有问题。具体来说，我使用Entity Framework with POCO作为实体，而我使用的DI是自定义的，但any of the ones out there会这样做。

更新

BL不知道DAL。

BL定义了一个接口（让我们称之为IRepository），它可以用来做它需要做的事情。
DAL定义了一个实现接口IRepository的类（Repository）。因此，存储库的实际实现是在DAL中。
显然，BL无法直接创建存储库的实例。这是依赖注入的来源，这允许开发人员创建一个通常无法完成的类的实例。一个简单粗略的版本是使用reflection。

我希望这更有意义。

Answer 2

您可以使用以下3层架构的示例代码： -

CLASS - BAL.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Collections;

public class BAL
{
    DAL objDAL;
    public BAL()
    {

    }

    public string _Name;
    public string Name
    {
        get { return _Name; }
        set { _Name = value; }
    }

    public int insert()
    {
        objDAL = new DAL();
        int val = 0;
        try
        {
            Hashtable objHash = new Hashtable();
            objHash.Add("@Name", Convert.ToString(_Name));
            val = objDAL.Insert("Your SP Name", objHash);
        }
        catch (Exception ex)
        {
            throw ex;
        }
        finally
        {
            objDAL = null;
        }
        return val;
    }
}

CLASS - DAL.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data;
using System.Data.SqlClient;
using System.Collections;

public class DAL : IDisposable
{
    SqlConnection con;

    public DAL()
    {
        con = new SqlConnection("Connection String");
    }

    public int Insert(string CMD, Hashtable objHash)
    {
        int val = 0;
        try
        {
            SqlCommand cmd1 = new SqlCommand(CMD, con);
            cmd1.CommandType = CommandType.StoredProcedure;
            foreach (DictionaryEntry de in objHash)
            {
                cmd1.Parameters.AddWithValue(Convert.ToString(de.Key), Convert.ToString(de.Value));
            }
            con.Open();
            val = cmd1.ExecuteNonQuery();
        }
        catch (Exception ex)
        {
            throw ex;
        }
        finally
        {
            con.Close();
        }
        return val;
    }

    #region IDisposable Members

    public void Dispose()
    {
        throw new NotImplementedException();
    }

    #endregion
}

UI： -

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class _Default : System.Web.UI.Page
{

    BAL objBAL;

    protected void Page_Load(object sender, EventArgs e)
    {
        Insert();
    }

    public void Insert()
    {
        int val = 0;
        objBAL = new BAL();
        objBAL.Name = "stackoverflow";
        try
        {
            val = objBAL.insert();
        }
        catch { }
        finally
        {
            objBAL = null;
        }
        if (val != 0)
        {
            //Insert sucessful
        }
        else
        {
            //Error in Insert.
        }
    }
}

Answer 3

可能会帮助您查看一些实际代码。我建议您下载NetTiers，针对您的数据库架构运行它，并查看输出的代码以了解实现细节。

Answer 4

using System;
using System.Data;
using System.Configuration;
using System.Collections.Generic;
using System.Text;
using System.Data.Common;
using System.Data.SqlClient;
using System.Data.OleDb;
using System.Data.Odbc;
using System.IO;
using System.ComponentModel;

namespace dal
{

    /// <summary>
    /// Summary description for Data Access Layer
    /// </summary>
    public class DataAccess
    {
        public string strConnectionString;
        private DbConnection objConnection;
        private DbCommand objCommand;
        private DbProviderFactory objFactory = null;
        private bool boolHandleErrors=false;
        private string strLastError;
        private bool boolLogError=false;
        private string strLogFile;

        public DataAccess()
        {

            //strConnectionString = ;
            strConnectionString = objCommon.GetConnectionString;
            objFactory = OleDbFactory.Instance;
            objConnection = objFactory.CreateConnection();
            objCommand = objFactory.CreateCommand();
            objConnection.ConnectionString = strConnectionString;
            objCommand.Connection = objConnection;
        }

        public bool HandleErrors
        {
            get
            {
                return boolHandleErrors;
            }
            set
            {
                boolHandleErrors = value;
            }
        }

        public string LastError
        {
            get
            {
                return strLastError;
            }
        }

        public bool LogErrors
        {
            get
-            {
                return boolLogError;
            }
            set
            {
                boolLogError = value;
            }
        }

        public string LogFile
        {
            get
            {
                return strLogFile;
            }
            set
            {
                strLogFile = value;
            }
        }

        public int AddParameter(string name, object value)
        {
            DbParameter p = objFactory.CreateParameter();
            p.ParameterName = name;
            p.Value = value;
            return objCommand.Parameters.Add(p);
        }

        public int AddParameter(string name, object value, ParameterDirection direction)
        {
            DbParameter p = objFactory.CreateParameter();
            p.ParameterName = name;
            p.Value = value;
            p.Direction = direction;
            return objCommand.Parameters.Add(p);
        }

        public int AddParameter(string name, object value, DbType type)
        {
            DbParameter p = objFactory.CreateParameter();
            p.ParameterName = name;
            p.Value = value;
            p.DbType = type;
            return objCommand.Parameters.Add(p);
        }

        public int AddParameter(DbParameter parameter)
        {
            return objCommand.Parameters.Add(parameter);
        }

        public DbCommand Command
        {
            get
            {
                return objCommand;
            }
        }

        public void BeginTransaction()
        {
            try
            {
                if (objConnection.State == System.Data.ConnectionState.Closed)
                {
                    objConnection.Open();
                }
                objCommand.Transaction = objConnection.BeginTransaction();
            }
            catch (Exception Ex)
            {
                HandleExceptions(Ex);
            }
        }

        public void CommitTransaction()
        {
            objCommand.Transaction.Commit();
            objConnection.Close();
        }

        public void RollbackTransaction()
        {
            objCommand.Transaction.Rollback();
            objConnection.Close();
        }

        public int ExecuteNonQuery(string query)
        {
            return ExecuteNonQuery(query, CommandType.Text, ConnectionState.CloseOnExit);
        }

        public int ExecuteNonQuery(string query, CommandType commandtype)
        {
            return ExecuteNonQuery(query, commandtype, ConnectionState.CloseOnExit);
        }

        public int ExecuteNonQuery(string query, ConnectionState connectionstate)
        {
            return ExecuteNonQuery(query, CommandType.Text, connectionstate);
        }

        public int ExecuteNonQuery(string query, CommandType commandtype, ConnectionState connectionstate)
        {
            objCommand.CommandText = query;
            objCommand.CommandType = commandtype;
            int i = -1;
            try
            {
                if (objConnection.State == System.Data.ConnectionState.Closed)
                {
                    objConnection.Open();
                }
                i = objCommand.ExecuteNonQuery();
            }
            catch (Exception ex)
            {
                HandleExceptions(ex);
            }
            finally
            {
                objCommand.Parameters.Clear();
                if (connectionstate == ConnectionState.CloseOnExit)
                {
                    objConnection.Close();
                }
            }

            return i;
        }

        public object ExecuteScalar(string query)
        {
            return ExecuteScalar(query, CommandType.Text, ConnectionState.CloseOnExit);
        }

        public object ExecuteScalar(string query, CommandType commandtype)
        {
            return ExecuteScalar(query, commandtype, ConnectionState.CloseOnExit);
        }

        public object ExecuteScalar(string query, ConnectionState connectionstate)
        {
            return ExecuteScalar(query, CommandType.Text, connectionstate);
        }

        public object ExecuteScalar(string query, CommandType commandtype, ConnectionState connectionstate)
        {
            objCommand.CommandText = query;
            objCommand.CommandType = commandtype;
            object o = null;
            try
            {
                if (objConnection.State == System.Data.ConnectionState.Closed)
                {
                    objConnection.Open();
                }
                o = objCommand.ExecuteScalar();
            }
            catch (Exception ex)
            {
                HandleExceptions(ex);
            }
            finally
            {
                objCommand.Parameters.Clear();
                if (connectionstate == ConnectionState.CloseOnExit)
                {
                    objConnection.Close();
                }
            }

            return o;
        }

        public DbDataReader ExecuteReader(string query)
        {
            return ExecuteReader(query, CommandType.Text, ConnectionState.CloseOnExit);
        }

        public DbDataReader ExecuteReader(string query, CommandType commandtype)
        {
            return ExecuteReader(query, commandtype, ConnectionState.CloseOnExit);
        }

        public DbDataReader ExecuteReader(string query, ConnectionState connectionstate)
        {
            return ExecuteReader(query, CommandType.Text, connectionstate);
        }

        public DbDataReader ExecuteReader(string query, CommandType commandtype, ConnectionState connectionstate)
        {
            objCommand.CommandText = query;
            objCommand.CommandType = commandtype;
            DbDataReader reader = null;
            try
            {
                if (objConnection.State == System.Data.ConnectionState.Closed)
                {
                    objConnection.Open();
                }
                if (connectionstate == ConnectionState.CloseOnExit)
                {
                    reader = objCommand.ExecuteReader(CommandBehavior.CloseConnection);
                }
                else
                {
                    reader = objCommand.ExecuteReader();
                }

            }
            catch (Exception ex)
            {
                HandleExceptions(ex);
            }
            finally
            {
                objCommand.Parameters.Clear();
            }

            return reader;
        }

        public DataSet ExecuteDataSet(string query)
        {
            return ExecuteDataSet(query, CommandType.Text, ConnectionState.CloseOnExit);
        }

        public DataSet ExecuteDataSet(string query, CommandType commandtype)
        {
            return ExecuteDataSet(query, commandtype, ConnectionState.CloseOnExit);
        }

        public DataSet ExecuteDataSet(string query, ConnectionState connectionstate)
        {
            return ExecuteDataSet(query, CommandType.Text, connectionstate);
        }

        public DataSet ExecuteDataSet(string query, CommandType commandtype, ConnectionState connectionstate)
        {
            DbDataAdapter adapter = objFactory.CreateDataAdapter();
            objCommand.CommandText = query;
            objCommand.CommandType = commandtype;
            adapter.SelectCommand = objCommand;
            DataSet ds = new DataSet();

            try
            {
                adapter.Fill(ds);
            }
            catch (Exception ex)
            {
                HandleExceptions(ex);
            }
            finally
            {
                objCommand.Parameters.Clear();
                if (connectionstate == ConnectionState.CloseOnExit)
                {
                    if (objConnection.State == System.Data.ConnectionState.Open)
                    {
                        objConnection.Close();
                    }
                }
            }
            return ds;
        }

        private void HandleExceptions(Exception ex)
        {

            throw ex;

        }

        private void WriteToLog(string msg)
        {
            StreamWriter writer = File.AppendText(LogFile);
            writer.WriteLine(DateTime.Now.ToString() + " - " + msg);
            writer.Close();
        }

        public void Dispose()
        {
            objConnection.Close();
            objConnection.Dispose();
            objCommand.Dispose();
        }



        public enum Providers
        {
            SqlServer, OleDb, Oracle, ODBC, ConfigDefined
        }

        public enum ConnectionState
        {
            KeepOpen, CloseOnExit
        }

        public interface ILoadFromDataRow
        {
            bool LoadFromDataRow(DataRow row);
        }


    }

}

在3层架构中使用BAL？如何从DAL调用方法到BAL

4 个答案:

更新