C#自定义Attribute的定义和获取简例 – 上校 – 博客园

来源: C#自定义Attribute的定义和获取简例 – 上校 – 博客园

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

namespace WebApplication4
{
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
abc ta = new abc();
Type type = ta.GetType();
GetTableName(type);

PropertyInfo[] propertys = type.GetProperties(BindingFlags.Public | BindingFlags.Instance);
FieldInfo[] fields = type.GetFields(BindingFlags.Public | BindingFlags.Instance);

foreach (PropertyInfo p in propertys)
{
//此处用了PropertyInfo.GetCustomAttributes方法,该方法继承至MemberInfo
object[] objs = p.GetCustomAttributes(false);
foreach (object obj in objs)
{
//string PK = GetPrimaryKey(obj);
string ColumnName = GetColumnName(obj);
}
}
}

public static string GetTableName(Type classType)
{
string strTableName = string.Empty;
string strEntityName = string.Empty;
string strTableTel = string.Empty;

strEntityName = classType.FullName;//类的全名

//此处用了System.Type.GetCustomAttributes 方法,该方法继承至MemberInfo object classAttr = classType.GetCustomAttributes(false)[0];
if (classAttr is TableAttribute)
{
TableAttribute tableAttr = classAttr as TableAttribute;
strTableName = tableAttr.Name;
strTableTel = tableAttr.Tel;
}
if (string.IsNullOrEmpty(strTableName))
{
throw new Exception(“实体类:” + strEntityName + “的属性配置[Table(name=\”tablename\”)]错误或未配置”);
}
if (string.IsNullOrEmpty(strTableTel))
{
throw new Exception(“实体类:” + strEntityName + “的属性配置[Table(tel=\”telname\”)]错误或未配置”);
}

return strTableName;
}

public static string GetPrimaryKey(object attribute)
{
string strPrimary = string.Empty;
IdAttribute attr = attribute as IdAttribute;
switch (attr.Strategy)
{
case GenerationType.INDENTITY:
break;
case GenerationType.SEQUENCE:
strPrimary = System.Guid.NewGuid().ToString();
break;
case GenerationType.TABLE:
break;
}

return strPrimary;
}

public static string GetColumnName(object attribute)
{
string columnName = string.Empty;
if (attribute is ColumnAttribute)
{
ColumnAttribute columnAttr = attribute as ColumnAttribute;
columnName = columnAttr.Name;
}
else if (attribute is IdAttribute)
{
IdAttribute idAttr = attribute as IdAttribute;
columnName = idAttr.Name;
}

return columnName;
}
}

[Table(Name = “Student”,Tel=”ew”)]
public class abc
{
private string _a = string.Empty;
[Id(Name = “studentid”, Strategy = GenerationType.INDENTITY)]
public string a
{
get { return _a; }
set { _a = value; }
}
private string _b = string.Empty;
[Column(Name = “studentno”)]
public string b
{
get { return _b; }
set { _b = value; }
}

public string c = string.Empty;
}

[AttributeUsage(AttributeTargets.Class, AllowMultiple = false, Inherited = false)]
public class TableAttribute : Attribute
{
public TableAttribute() { }

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

private string _Tel = string.Empty;
public string Tel
{
get { return _Tel; }
set { _Tel = value; }
}
}

[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property, AllowMultiple = false, Inherited = false)]
public class IdAttribute : Attribute
{
private string _Name = string.Empty;
private int _Strategy = GenerationType.INDENTITY;

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

public int Strategy
{
get { return _Strategy; }
set { _Strategy = value; }
}
}

public class GenerationType
{
public const int INDENTITY = 1;//自动增长
public const int SEQUENCE = 2;//序列
public const int TABLE = 3;//TABLE

private GenerationType() { }//私有构造函数,不可被实例化对象
}

[AttributeUsage(AttributeTargets.Field | AttributeTargets.Property,
AllowMultiple = false, Inherited = false)]
public class ColumnAttribute : Attribute
{
public ColumnAttribute() { }

private string _Name = string.Empty;//列名
private bool _IsUnique = false;//是否唯一
private bool _IsNull = true;//是否允许为空
private bool _IsInsert = true;//是否插入到表中
private bool _IsUpdate = true;//是否修改到表中

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

public bool IsUnique
{
get { return _IsUnique; }
set { _IsUnique = value; }
}

public bool IsNull
{
get { return _IsNull; }
set { _IsNull = value; }
}

public bool IsInsert
{
get { return _IsInsert; }
set { _IsInsert = value; }
}

public bool IsUpdate
{
get { return _IsUpdate; }
set { _IsUpdate = value; }
}
}
}

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