通用数据访问层框架

1.框架

定义实体类、数据访问类的基类，以及用户ORMapping的Attribute。

TableMappingAttribute：

using System;

namespace Core
{
    [AttributeUsage(AttributeTargets.Class)]
    public class TableMappingAttribute : Attribute
    {
        public String TableName {get;set;}
    }
}

FieldMappingAttribute：

using System;

namespace Core
{
    [AttributeUsage(AttributeTargets.Property)]
    public class FieldMappingAttribute : Attribute
    {
        public String FieldName {get;set;}

        public Boolean IsPrimary {get;set;}

        public Boolean IsAutoIncrement {get;set;}
    }
}

EntityBase：

using System;

namespace Core
{
    public class EntityBase
    {
        Boolean isNew = true;
        public Boolean IsNew
        {
            get { return isNew; }
            set
            {
                isNew = value;
                if (isNew == true)
                {
                    isLoad = false;
                    isDeleted = false;
                    isDirty = false;
                }
            }
        }

        Boolean isDirty = false;
        public Boolean IsDirty
        {
            get { return isDirty; }
            set
            {
                if (isLoad)
                {
                    isDirty = value;
                }
            }
        }

        Boolean isLoad = false;
        public Boolean IsLoad
        {
            get { return isLoad; }
            set
            {
                isLoad = value;
                if (isLoad == true)
                {
                    isNew = false;
                    isDeleted = false;
                    isDirty = false;
                }
            }
        }

        Boolean isDeleted = false;
        public Boolean IsDeleted
        {
            get { return isDeleted; }
            set
            {
                isDeleted = value;
                if (isDeleted == true)
                {
                    isNew = false;
                    isLoad = false;
                    isDirty = false;
                }
            }
        }
    }
}

ServiceBase：

using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.Reflection;

namespace Core
{
    public class ServiceBase<T> where T : EntityBase
    {
        #region 保护字段
        protected SqlConnection m_DalConnection = null;
        protected SqlCommand m_DalCommand = null;
        protected Dictionary<String, SqlParameter> m_DalCachedParameters = null;
        #endregion

        #region 私有字段
        private String m_TableName = string.Empty;
        private String m_SelectSql = string.Empty;
        private String m_InsertSql = string.Empty;
        private String m_UpdateSql = string.Empty;
        private PropertyInfo m_PrimaryFieldPropertyInfo = null;
        private PropertyInfo m_AutoIncrementFieldPropertyInfo = null;
        private Dictionary<String, PropertyInfo> m_CachedFieldPropertyInfo = null;
        private DataTable m_TemplateDataTable = null;
        #endregion

        #region 构造函数
        protected ServiceBase(SqlConnection sqlConnection)
        {
            m_DalConnection = sqlConnection;
            m_DalCommand = new SqlCommand();
            m_DalCommand.CommandTimeout = 150;
            m_DalCommand.Connection = m_DalConnection;

            m_DalCachedParameters = new Dictionary<String, SqlParameter>();
            m_CachedFieldPropertyInfo = new Dictionary<String, PropertyInfo>();

            InitTableFieldMaping();
        }

        private void InitTableFieldMaping()
        {
            var tableMappingAttributes = typeof(T).GetCustomAttributes(typeof(TableMappingAttribute), false) as TableMappingAttribute[];
            if (tableMappingAttributes.Length == 0)
            {
                throw new ApplicationException("Miss TableMappingAttribute defination");
            }
            m_TableName = tableMappingAttributes[0].TableName;

            String updateSetSql = string.Empty;
            String updateWhereSql = string.Empty;
            String insertFieldsSql = string.Empty;
            String insertValuesSql = string.Empty;
            foreach (PropertyInfo propertyInfo in typeof(T).GetProperties())
            {
                var fieldMappingAttributes = propertyInfo.GetCustomAttributes(typeof(FieldMappingAttribute), false) as FieldMappingAttribute[];
                if (fieldMappingAttributes.Length > 0)
                {
                    String fieldName = fieldMappingAttributes[0].FieldName;
                    m_CachedFieldPropertyInfo.Add(fieldName, propertyInfo);

                    bool isPrimaryField = fieldMappingAttributes[0].IsPrimary;
                    bool isAutoIncrementField = fieldMappingAttributes[0].IsAutoIncrement;

                    if (isPrimaryField)
                    {
                        if (m_PrimaryFieldPropertyInfo != null)
                        {
                            throw new ApplicationException("Muiltiple Primary Field defination");
                        }
                        m_PrimaryFieldPropertyInfo = propertyInfo;
                    }

                    if (isAutoIncrementField)
                    {
                        if (m_AutoIncrementFieldPropertyInfo != null)
                        {
                            throw new ApplicationException("Muiltiple Auto Increment Field defination");
                        }
                        m_AutoIncrementFieldPropertyInfo = propertyInfo;
                    }

                    //SELECT SQL
                    if (m_SelectSql == string.Empty)
                    {
                        m_SelectSql = "[" + fieldName + "]";
                    }
                    else
                    {
                        m_SelectSql += ",[" + fieldName + "]";
                    }

                    //INSERT SQL
                    if (!isAutoIncrementField)
                    {
                        if (insertFieldsSql == string.Empty)
                        {
                            insertFieldsSql += "[" + fieldName + "]";
                            insertValuesSql += "@" + fieldName;
                        }
                        else
                        {
                            insertFieldsSql += ",[" + fieldName + "]";
                            insertValuesSql += ",@" + fieldName;
                        }
                    }

                    //UPDATE SQL
                    if (isPrimaryField)
                    {
                        if (updateWhereSql == string.Empty)
                        {
                            updateWhereSql = " WHERE [" + fieldName + "] = @" + fieldName;
                        }
                        else
                        {
                            updateWhereSql += " AND [" + fieldName + "] = @" + fieldName;
                        }
                    }
                    else if (!isAutoIncrementField)
                    {
                        if (updateSetSql == string.Empty)
                        {
                            updateSetSql = " SET [" + fieldName + "] = @" + fieldName;
                        }
                        else
                        {
                            updateSetSql += ",[" + fieldName + "] = @" + fieldName;
                        }
                    }
                    string parameterName = "@" + fieldName;
                    m_DalCachedParameters.Add(parameterName, CreateSqlParameterByProperty(propertyInfo, parameterName));
                }
            }

            if (m_PrimaryFieldPropertyInfo == null)
            {
                throw new ApplicationException("Miss Primary Field defination");
            }

            m_InsertSql = "INSERT " + m_TableName + " (" + insertFieldsSql + ")" + " VALUES(" + insertValuesSql + ")";
            m_UpdateSql = "UPDATE " + m_TableName + updateSetSql + updateWhereSql;
        }
        #endregion

        #region 公共方法
        protected void OpenConnection()
        {
            if (m_DalConnection.State == System.Data.ConnectionState.Closed)
            {
                m_DalConnection.Open();
            }
        }

        protected void CloseConnection()
        {
            if (m_DalConnection.State == System.Data.ConnectionState.Open)
            {
                m_DalConnection.Close();
            }
        }

        public DataTable GetTemplateDataTable()
        {
            if (m_TemplateDataTable == null)
            {
                try
                {
                    OpenConnection();

                    m_DalCommand.Parameters.Clear();
                    m_DalCommand.CommandText = "SELECT TOP 0 " + m_SelectSql + " FROM " + m_TableName;
                    SqlDataAdapter daDataAdapter = new SqlDataAdapter(m_DalCommand);

                    DataTable result = new DataTable();
                    daDataAdapter.Fill(result);
                    m_TemplateDataTable = result;
                }
                finally
                {
                    CloseConnection();
                }
            }

            return m_TemplateDataTable.Clone();
        }

        public void BulkCopyDataTable(DataTable dataTable)
        {
            try
            {
                OpenConnection();

                SqlBulkCopy daBulkCopy = new SqlBulkCopy(m_DalConnection);
                daBulkCopy.BulkCopyTimeout = 10000;
                daBulkCopy.DestinationTableName = "[" + m_TableName + "]";
                daBulkCopy.WriteToServer(dataTable);
            }
            finally
            {
                CloseConnection();
            }
        }
        #endregion

        #region 保护方法
        protected Int32 CountObjects(String where)
        {
            Int32 result = 0;
            try
            {
                OpenConnection();

                m_DalCommand.CommandText = "SELECT COUNT(*) FROM " + m_TableName + " " + where;
                result = Convert.ToInt32(m_DalCommand.ExecuteScalar());
            }
            finally
            {
                CloseConnection();
            }

            return result;
        }

        protected List<T> SelectObjects(String where)
        {
            return SelectObjects(where, String.Empty, String.Empty, String.Empty);
        }

        protected List<T> SelectObjects(String where, String with)
        {
            return SelectObjects(where, with, String.Empty, String.Empty);
        }

        protected List<T> SelectObjects(String where, String with, String order)
        {
            return SelectObjects(where, with, String.Empty, order);
        }

        protected List<T> SelectObjects(String where, String with, String top, String order)
        {
            List<T> objects = new List<T>();
            try
            {
                OpenConnection();

                m_DalCommand.CommandText = "SELECT " + top + " " + m_SelectSql + " FROM " + m_TableName + " " + with + " " + where + order;
                using (SqlDataReader dataReader = m_DalCommand.ExecuteReader())
                {
                    while (dataReader.Read())
                    {
                        objects.Add(ReadObjectFromDataReader(dataReader));
                    }
                }
            }
            finally
            {
                CloseConnection();
            }

            return objects;
        }

        protected Int32 DeleteObjects(String where)
        {
            try
            {
                OpenConnection();

                m_DalCommand.CommandText = "DELETE FROM " + m_TableName + " " + where;
                return m_DalCommand.ExecuteNonQuery();
            }
            finally
            {
                CloseConnection();
            }
        }

        protected Int32 InsertObject(T obj)
        {
            try
            {
                OpenConnection();

                m_DalCommand.CommandText = m_InsertSql;
                m_DalCommand.Parameters.Clear();
                foreach (String key in m_CachedFieldPropertyInfo.Keys)
                {
                    m_DalCachedParameters["@" + key].Value = m_CachedFieldPropertyInfo[key].GetValue(obj, null);
                    m_DalCommand.Parameters.Add(m_DalCachedParameters["@" + key]);
                }
                int count = m_DalCommand.ExecuteNonQuery();

                if (count > 0 && m_AutoIncrementFieldPropertyInfo != null)
                {
                    m_DalCommand.CommandText = "SELECT @@IDENTITY";
                    m_DalCommand.Parameters.Clear();
                    Object ObjID = m_DalCommand.ExecuteScalar();
                    SetValueForProperty(m_AutoIncrementFieldPropertyInfo, obj, ObjID);
                }

                obj.IsLoad = count > 0;

                return count;
            }
            finally
            {
                CloseConnection();
            }
        }

        protected Int32 UpdateObject(T obj)
        {
            try
            {
                OpenConnection();

                m_DalCommand.CommandText = m_UpdateSql;

                m_DalCommand.Parameters.Clear();
                foreach (String key in m_CachedFieldPropertyInfo.Keys)
                {
                    m_DalCachedParameters["@" + key].Value = m_CachedFieldPropertyInfo[key].GetValue(obj, null);
                    m_DalCommand.Parameters.Add(m_DalCachedParameters["@" + key]);
                }

                int count = m_DalCommand.ExecuteNonQuery();

                obj.IsLoad = count > 0;

                return count;
            }
            finally
            {
                CloseConnection();
            }
        }
        #endregion

        #region 私有方法
        private T ReadObjectFromDataReader(SqlDataReader dataReader)
        {
            T result = (T)Activator.CreateInstance(typeof(T));

            foreach (String key in m_CachedFieldPropertyInfo.Keys)
            {
                SetValueForProperty(m_CachedFieldPropertyInfo[key], result, dataReader[key]);
            }

            result.IsLoad = true;

            return result;
        }

        private void SetValueForProperty(PropertyInfo propertyInfo, object obj, object value)
        {
            switch (propertyInfo.PropertyType.FullName)
            {
                case "System.String":
                    propertyInfo.SetValue(obj, value as string, null);
                    break;
                case "System.Int32":
                    propertyInfo.SetValue(obj, Convert.ToInt32(value), null);
                    break;
                case "System.Boolean":
                    propertyInfo.SetValue(obj, (bool)value, null);
                    break;
                case "System.DateTime":
                    propertyInfo.SetValue(obj, (DateTime)value, null);
                    break;
            }
        }

        private SqlParameter CreateSqlParameterByProperty(PropertyInfo propertyInfo, string parameterName)
        {
            switch (propertyInfo.PropertyType.FullName)
            {
                case "System.String":
                    return new SqlParameter(parameterName, SqlDbType.VarChar);
                case "System.Int32":
                    return new SqlParameter(parameterName, SqlDbType.Int);
                case "System.Boolean":
                    return new SqlParameter(parameterName, SqlDbType.Bit);
                case "System.DateTime":
                    return new SqlParameter(parameterName, SqlDbType.DateTime);
                default:
                    return null;
            }
        }
        #endregion
    }
}

2.应用

定义Project实体类：

using System;
using Core;

namespace Entity
{
    [Serializable]
    [TableMapping(TableName="tabProject")]
    public class Project:EntityBase
    {
        String projectID = string.Empty;
        [FieldMapping(FieldName = "ProjectID",IsPrimary=true)]
        public String ProjectID
        {
            get { return projectID; }
            set { IsDirty |= (projectID != value); projectID = value; }
        }

        String projectName = string.Empty;
        [FieldMapping(FieldName = "ProjectName")]
        public String ProjectName
        {
            get { return projectName; }
            set { IsDirty |= (projectName != value); projectName = value; }
        }
    }
}

定义ProjectService 数据访问类;

using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using Core;
using Entity;

namespace Service
{
    public class ProjectService : ServiceBase<Project>
    {
        #region 常量字段
        const String SQL_WHERE_ID = "WHERE ProjectID = @ProjectID";
        const String SQL_PARAM_PROJECTID = "@ProjectID";
        const String SQL_PARAM_PROJECTNAME = "@ProjectName";
        #endregion

        #region 构造函数
        public ProjectService(SqlConnection sqlConnection)
            : base(sqlConnection)
        {
        }
        #endregion

        #region 获取方法
        public Project GetProjectByID(String projectID)
        {
            m_DalCommand.Parameters.Clear();
            m_DalCachedParameters[SQL_PARAM_PROJECTID].Value = projectID;
            m_DalCommand.Parameters.Add(m_DalCachedParameters[SQL_PARAM_PROJECTID]);
            List<Project> projects = base.SelectObjects(SQL_WHERE_ID);
            return projects.Count > 0 ? projects[0] : null;
        }
        public List<Project> GetAllProjects()
        {
            m_DalCommand.Parameters.Clear();
            return base.SelectObjects(string.Empty);
        }
        #endregion

        #region 保存方法
        public Int32 InsertProject(Project project)
        {
            return base.InsertObject(project);
        }
        public Int32 UpdateProject(Project project)
        {
            return base.UpdateObject(project);
        }
        #endregion

        #region 删除方法
        public Int32 DeleteProjectByID(String projectID)
        {
            m_DalCommand.Parameters.Clear();
            m_DalCachedParameters[SQL_PARAM_PROJECTID].Value = projectID;
            m_DalCommand.Parameters.Add(m_DalCachedParameters[SQL_PARAM_PROJECTID]);

            return base.DeleteObjects(SQL_WHERE_ID);
        }
        #endregion
    }
}

使用：

Get：

ProjectService ps = new ProjectService(new SqlConnection(@"Data Source=.\SQLEXPRESS;Initial Catalog=Database1;Integrated Security=True"));
List<Project> projects = ps.GetAllProjects();

Insert：

ProjectService projectService = new ProjectService(new SqlConnection(@"Data Source=.\SQLEXPRESS;Initial Catalog=Database1;Integrated Security=True")); 
Project project = new Project(); 
project.ProjectID = "1000"; 
project.ProjectName = "Test"; 
projectService.InsertProject(project);

Update：

ProjectService projectService = new ProjectService(new SqlConnection(@"Data Source=.\SQLEXPRESS;Initial Catalog=Database1;Integrated Security=True")); 
Project project = new Project(); 
project.ProjectID = "1000"; 
project.ProjectName = "Hello"; 
projectService.UpdateProject(project);

Delete：

ProjectService projectService = new ProjectService(new SqlConnection(@"Data Source=.\SQLEXPRESS;Initial Catalog=Database1;Integrated Security=True")); 
projectService.DeleteProjectByID("1000");