把DataTable自动转换出Object对象集

最新推荐文章于 2023-03-10 11:59:24 发布

原创最新推荐文章于 2023-03-10 11:59:24 发布 · 4.1k 阅读

3 ·

CC 4.0 BY-SA版权

文章标签：

#object #string #list #class #数据库 #sms

大家好，这是我第一次在优快云上发表我的文章，希望得到前辈们的支持和指点。
言归正传，由于一个实例对象中包括的字段和属性很多，而每次在从数据库中取出对象时，写的类似如下的代码就会很多很多，我每次写这些代码的时候心情会很烦。

int ID = int .Parse(dt.Rows[ 0 ][ " id " ].ToString());

string McOK = int .Parse(dt.Rows[ 0 ][ " mcok " ].ToString()) == 1 ? true : false ;

string Pass = dt.Rows[ 0 ][ " pass " ].ToString();

string Sms_extend = dt.Rows[ 0 ][ " sms_extend " ].ToString();

string UserName = dt.Rows[ 0 ][ " username " ].ToString();

string Content_MB = dt.Rows[ 0 ][ " content_mb " ].ToString();

不知道你们有没有这种烦的感觉呢！为了让大家永远离开这种烦恼，我就把我的解决办法奉献出来，能给你带来帮助。

我的解决办法是通过对字段或属性添加自定义属性(System.Attribute)，以及通过反射(System.Reflection;)来实现的。

首先，添加一个自定义属性类，用于修饰字段和属性，使得对象中的字段与数据库中的字段一一对应起来，没有对应到的字段或都属性就不用修饰，呵呵，代码如下：

// --->属性标记

/// <summary>

/// 对属性或字段应用属性

/// </summary>

[System.AttributeUsage(AttributeTargets.Property | System.AttributeTargets.Field, AllowMultiple = true )]

public class ObjectFieldAttribute : System.Attribute

{

public ObjectFieldAttribute(string name)

{

FieldName = name;

}

public string FieldName;//相关方法的名称

}

接下来添加一个MyInclude类，类里添加一个静态方法GetObject方法，用于从DataTable中自动取得对象，在这里我返回的是范型(System.Collections.Generic.List)的Object，之后可以自由转换成各类实例对象。代码如下：

public class MyInclude

... {

public MyInclude()

...{

// TODO: 在此处添加构造函数逻辑

} /**//// <summary>

/// 通过字段、属性和方法等的标记从DataTable返回Object对象,是范型List

/// </summary>

/// <param name="obj">需要返回的Object对象类型</param>

/// <param name="dt">传入的DataTable对象</param>

/// <returns>返回范型List</returns>

public static Object GetObject(Type type, DataTable dt)

...{

string methodName = new System.Diagnostics.StackTrace().GetFrame(1).GetMethod().Name;

object list = MyInclude.CreateListFromType(type);

Type listType = list.GetType();

MethodInfo methodInfo = listType.GetMethod("Add");

for (int i = 0; i < dt.Rows.Count; i++)

...{

Object obj = Activator.CreateInstance(type);

MemberInfo[] members = type.GetMembers();

foreach (MemberInfo member in members)

...{

Object[] objes = member.GetCustomAttributes(true);

foreach (Object obje in objes)

...{

if (obje.GetType() == typeof(ObjectFieldAttribute) && member.MemberType == System.Reflection.MemberTypes.Field)

...{

((FieldInfo)member).SetValue(obj, MyInclude.ConvertObject(dt.Rows[i][((ObjectFieldAttribute)obje).FieldName], ((FieldInfo)member).FieldType));

}

if (obje.GetType() == typeof(ObjectFieldAttribute) && member.MemberType == System.Reflection.MemberTypes.Property)

...{

((PropertyInfo)member).SetValue(obj, MyInclude.ConvertObject(dt.Rows[i][((ObjectFieldAttribute)obje).FieldName], ((PropertyInfo)member).PropertyType), null);

}

methodInfo.Invoke(list, new object[] ...{ obj });

}

return list;

}

/// <summary>

/// 通过指定类型创建范型List

/// </summary>

/// <param name="type">类型参数</param>

/// <returns></returns>

public static Object CreateListFromType(Type type)

{

//创建范型List<>

string typeName= "System.Collections.Generic.List`1[[" + type.FullName + "]]";

Type listType = Type.GetType(typeName);

return Activator.CreateInstance(listType);

}

至此，要解决问题的代码已经完成，接下来，就是应用，我就添加一个类，来如何实现自动转换，类的代码如下：

using System;

using System.Data;

using System.Configuration;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.Collections.Generic;

/// <summary>

/// 客房预订信息

/// </summary>

public class Booking

{

public Booking()

{

}

public Booking(int id)

{

ID = id;

}

/// <summary>

/// 自动编号

/// </summary>

[ObjectField("ID")]

public int ID = 0;

/// <summary>

/// 客房编号

/// </summary>

[ObjectField("RoomID")]

public int RoomID = 0;

/// <summary>

/// 入住时间

/// </summary>

[ObjectField("InTime")]

public string InTime = string.Empty;

/// <summary>

/// 退房时间

/// </summary>

[ObjectField("OutTime")]

public string OutTime = string.Empty;

/// <summary>

/// 您的姓名

/// </summary>

[ObjectField("Name")]

public string Name = string.Empty;

/// <summary>

/// 性别

/// </summary>

[ObjectField("Sex")]

public int Sex = 0;

/// <summary>

/// 证件号码

/// </summary>

[ObjectField("DocumentsNum")]

public string DocumentsNum = string.Empty;

/// <summary>

/// 手机号码

/// </summary>

[ObjectField("Mobile")]

public string Mobile = string.Empty;

/// <summary>

/// 电话号码

/// </summary>

[ObjectField("Tel")]

public string Tel = string.Empty;

/// <summary>

/// 邮件地址

/// </summary>

[ObjectField("Email")]

public string Email = string.Empty;

/// <summary>

/// 房间数

/// </summary>

[ObjectField("RoomNum")]

public string RoomNum = string.Empty;

/// <summary>

/// 确认方式

/// </summary>

[ObjectField("ConfirmWay")]

public int ConfirmWay = 0;

/// <summary>

/// 其它要求

/// </summary>

[ObjectField("Other")]

public string Other = string.Empty;

/// <summary>

/// 预订者ＩＰ地址

/// </summary>

[ObjectField("IP")]

public string IP = string.Empty;

/// <summary>

/// 预订时间

/// </summary>

[ObjectField("AddTime")]

public DateTime AddTime = DateTime.MinValue;

/// <summary>

/// 处理结果

/// </summary>

[ObjectField("Confirmed")]

public int Confirmed = 0;

/// <summary>

/// 备注

/// </summary>

[ObjectField("Remarks")]

public string Remarks = string.Empty;

/// <summary>

/// 通过ID获得预订信息

/// </summary>

/// <param name="id"></param>

/// <returns></returns>

[DbAccess.SQLExecute(DbAccess.SQLExecuteType.DataTable)]

public static Booking GetBookingByID(int id)

{

Booking booking = new Booking();

booking.ID = id;

DbAccess.DbAccess db = GetDbAccess();

db.Sql = "select * from booking where id=@ID";

//获得DataTable

DataTable dt = (DataTable)DbAccess.DbAccess.Execute(booking, db);

if (dt.Rows.Count > 0)

{

//重要方法的调用在这里

Object obj = MyInclude.GetObject(typeof(Booking), dt);

if (((List<Booking>)obj).Count > 0)

{

return ((List<Booking>)obj)[0];

}

//这上面没有用到任何关于dt.Rows[0][""]的这符串，呵呵，成功！

}

return null;

}

/// <summary>

/// 建立数据库连接

/// </summary>

/// <returns></returns>

public static DbAccess.DbAccess GetDbAccess()

{

return DbBase.GetDbAccess();

}

接下来在页面中演示：请看代码：

using System;

using System.Data;

using System.Configuration;

using System.Collections;

using System.Web;

using System.Web.Security;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Web.UI.WebControls.WebParts;

using System.Web.UI.HtmlControls;

using System.Collections.Generic;

using System.Reflection;

public partial class temp1 : System.Web.UI.Page

{

protected void Page_Load(object sender, EventArgs e)

{

DataTable dt = Booking.GetAllBooking();

List<Booking> list = (List<Booking>)Booking.GetObjectList(typeof(Booking), dt);

Booking booking = Booking.GetBookingByID(3);

if (booking != null)

{

Response.Write(booking.AddTime.ToString() + " ");

Response.Write(booking.Confirmed.ToString() + " ");

Response.Write(booking.ConfirmWay.ToString() + " ");

Response.Write(booking.DocumentsNum + " ");

Response.Write(booking.Email + " ");

Response.Write(booking.ID.ToString() + " ");

Response.Write(booking.InTime.ToString() + " ");

Response.Write(booking.IP.ToString() + " ");

Response.Write(booking.Mobile + " ");

Response.Write(booking.Name + " ");

Response.Write(booking.Other + " ");

Response.Write(booking.OutTime.ToString() + " ");

Response.Write(booking.Remarks + " ");

Response.Write(booking.RoomID.ToString() + " ");

Response.Write(booking.RoomNum + " ");

Response.Write(booking.Sex.ToString() + " ");

Response.Write(booking.Tel + " ");

}

至此，功能全部实现，上边用到的对象中的字段或属性类型均是系统基本类型，如果其中的字段或都属性是自定义的对象，用以上的代码均能实现，在这里不多说了，大家慢慢考虑，呵呵！

不知道大家有没有理解，呵呵！如果觉得有哪些不合理的地方，请告诉我，我再改进，实际上我只是个菜鸟，还要不断得学啊！如果要交流的话，请加我QQ号：36759519,加我好友时请注明“C#.net交流”或者发我邮箱：xuejianfeng@jx0573.com