可绑定到成员变量的Attribute。
可绑定到成员变量上的Attribute
1using System; 2using System.Reflection; 3using System.ComponentModel; 4 5namespace Relaction.Attribute_in_member_field 6{ 7 public interface IFieldShow 8 { 9 string Show(object o);10 }11 /**//// <summary>12 /// 可用于字段或属性的自定义属性。13 /// </summary>14 /// 15 [AttributeUsage(AttributeTargets.Field|AttributeTargets.Property,Inherited = false,AllowMultiple=false)]16 public class FieldShowAttribute:Attribute17 {18 private bool _show = false;19 private Type _showclass = null;20 public bool Show21 {22 get23 {24 return _show;25 }26 }27 public Type ShowClass28 {29 get 30 {31 return _showclass;32 }33 }34 public FieldShowAttribute(bool show,Type showclass)35 {36 _show = show;37 _showclass = showclass;38 if(_showclass == null)39 {40 throw(new Exception("出错！"));41 }42 }43 public IFieldShow CreateShowInstance()44 {45 object o ;46 ConstructorInfo cinfo = _showclass.GetConstructor(new Type[]{});47 o = cinfo.Invoke(null);48 return (IFieldShow)o;49 }50 }51}
测试上面的属性：
测试上面的属性
1using System; 2 3namespace Relaction.Attribute_in_member_field 4{ 5 /**//// <summary> 6 /// 测试字段和属性的自定义属性晕， 7 /// </summary> 8 public class StringFieldShow:IFieldShow 9 {10 public StringFieldShow()11 {12 }13 IFieldShow 成员#region IFieldShow 成员1415 public string Show(object o)16 {17 return o.ToString();18 }1920 #endregion21 }22 public class AttrFieldTest23 {24 [FieldShow(true,typeof(StringFieldShow))]25 public int _num = 0;2627 public AttrFieldTest()28 {29 }30 }31}
测试：
测试
1 private void button3_Click(object sender, System.EventArgs e) 2 { 3 AttrFieldTest[] o = new AttrFieldTest[]{new AttrFieldTest(),new AttrFieldTest()}; 4 o[0]._num = 15; 5 o[1]._num = 30; 6 foreach(AttrFieldTest item in o) 7 { 8 foreach(FieldInfo field in item.GetType().GetFields()) 9 {10 FieldShowAttribute[] fattr = (FieldShowAttribute[])field.GetCustomAttributes(typeof(FieldShowAttribute),false);11 if(fattr.Length != 0)12 {13 label1.Text += field.Name+fattr[0].CreateShowInstance().Show(field.GetValue(item));14 }15 }16 }17 }
不是很理解。呵呵
也可以用表态的：
修改后的FieldShowAttribute
1using System; 2using System.Reflection; 3using System.ComponentModel; 4 5namespace Relaction.Attribute_in_member_field 6{ 7 public interface IFieldShow 8 { 9 string Show(object o);10 }11 /**//// <summary>12 /// 可用于字段或属性的自定义属性。13 /// </summary>14 /// 15 [AttributeUsage(AttributeTargets.Field|AttributeTargets.Property,Inherited = false,AllowMultiple=false)]16 public class FieldShowAttribute:Attribute17 {18 public FieldShowAttribute(bool show,Type showclass)19 {20 _show = show;21 _showclass = showclass;22 if(_showclass == null)23 {24 throw(new Exception("出错！"));25 }26 }272829 public bool Show30 {31 get32 {33 return _show;34 }35 }private bool _show = false;3637 public Type ShowClass38 {39 get 40 {41 return _showclass;42 }43 }private Type _showclass = null;44 45 public IFieldShow CreateShowInstance()46 {47 object o ;48 ConstructorInfo cinfo = _showclass.GetConstructor(new Type[]{});49 o = cinfo.Invoke(null);50 return (IFieldShow)o;51 }52 public static string ShowValue(FieldShowAttribute attr,object o,FieldInfo valueobject)53 {54 MethodInfo mi = attr.ShowClass.GetMethod("Show",BindingFlags.Static|BindingFlags.Public);55 return (string)mi.Invoke(null,new object[]{valueobject.GetValue(o)});56 }57 }58}59
修改后贴上FieldShowAttribute类
1using System; 2 3namespace Relaction.Attribute_in_member_field 4{ 5 /**//// <summary> 6 /// 测试字段和属性的自定义属性 7 /// </summary> 8 public class StringFieldShow:IFieldShow 9 {10 public StringFieldShow()11 {12 }13 IFieldShow 成员#region IFieldShow 成员1415 public string Show(object o)16 {17 return o.ToString();18 }1920 #endregion21 }22 public class StringFieldShow223 {24 public static string Show(object o)25 {26 return o.ToString();27 }28 }29 public class AttrFieldTest30 {31 [FieldShow(true,typeof(StringFieldShow2))]32 public int _num = 0;3334 public AttrFieldTest()35 {36 }37 }38}39
客户调用
1 private void button4_Click(object sender, System.EventArgs e) 2 { 3 AttrFieldTest[] o = new AttrFieldTest[]{new AttrFieldTest(),new AttrFieldTest()}; 4 o[0]._num = 15; 5 o[1]._num = 30; 6 foreach(AttrFieldTest item in o) 7 { 8 foreach(FieldInfo field in item.GetType().GetFields()) 9 {10 FieldShowAttribute[] fattr = (FieldShowAttribute[])field.GetCustomAttributes(typeof(FieldShowAttribute),false);11 if(fattr.Length != 0)12 {13 label1.Text += FieldShowAttribute.ShowValue(fattr[0],item,field);14 }15 }16 }17 }
转载于:https://www.cnblogs.com/nanshouyong326/archive/2006/11/27/573545.html
