C#的動態對象的屬性實現比較簡單,如果要實現動態語言那種動態方法就比較困難,因為對於dynamic對象,擴展方法,匿名方法都是不能用直接的,這裡還是利用對象和委托來模擬這種動態方法的實現,看起來有點javascript的對象味道:
1)定義一個委托,參數個數可變,參數都是object類型:這裡的委托多有個dynamic參數,代表調用這個委托的動態對象本身.
[csharp]
public delegate object MyDelegate(dynamic Sender, params object[] PMs);
public delegate object MyDelegate(dynamic Sender, params object[] PMs);
2)定義一個委托轉載對象,因為dynamic對象不能直接用匿名方法,這裡用對象去承載:
[csharp]
public class DelegateObj
{
private MyDelegate _delegate;
public MyDelegate CallMethod
{
get { return _delegate; }
}
private DelegateObj(MyDelegate D)
{
_delegate = D;
}
/// <summary>
/// 構造委托對象，讓它看起來有點javascript定義的味道.
/// </summary>
/// <param name="D"></param>
/// <returns></returns>
public static DelegateObj Function(MyDelegate D)
{
return new DelegateObj(D);
}
}
public class DelegateObj
{
private MyDelegate _delegate;
public MyDelegate CallMethod
{
get { return _delegate; }
}
private DelegateObj(MyDelegate D)
{
_delegate = D;
}
/// <summary>
/// 構造委托對象，讓它看起來有點javascript定義的味道.
/// </summary>
/// <param name="D"></param>
/// <returns></returns>
public static DelegateObj Function(MyDelegate D)
{
return new DelegateObj(D);
}
}
3) 定義一個動態對象:
[csharp]
public class DynObj : DynamicObject
{
//保存對象動態定義的屬性值
private Dictionary<string, object> _values;
public DynObj()
{
_values = new Dictionary<string, object>();
}
/// <summary>
/// 獲取屬性值
/// </summary>
/// <param name="propertyName"></param>
/// <returns></returns>
public object GetPropertyValue(string propertyName)
{
if (_values.ContainsKey(propertyName) == true)
{
return _values[propertyName];
}
return null;
}
/// <summary>
/// 設置屬性值
/// </summary>
/// <param name="propertyName"></param>
/// <param name="value"></param>
public void SetPropertyValue(string propertyName,object value)
{
if (_values.ContainsKey(propertyName) == true)
{
_values[propertyName] = value;
}
else
{
_values.Add(propertyName, value);
}
}
/// <summary>
/// 實現動態對象屬性成員訪問的方法，得到返回指定屬性的值
/// </summary>
/// <param name="binder"></param>
/// <param name="result"></param>
/// <returns></returns>
public override bool TryGetMember(GetMemberBinder binder, out object result)
{
result = GetPropertyValue(binder.Name);
return result == null ? false : true;
}
/// <summary>
/// 實現動態對象屬性值設置的方法。
/// </summary>
/// <param name="binder"></param>
/// <param name="value"></param>
/// <returns></returns>
public override bool TrySetMember(SetMemberBinder binder, object value)
{
SetPropertyValue(binder.Name, value);
return true;
}
/// <summary>
/// 動態對象動態方法調用時執行的實際代碼
/// </summary>
/// <param name="binder"></param>
/// <param name="args"></param>
/// <param name="result"></param>
/// <returns></returns>
public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result)
{
var theDelegateObj = GetPropertyValue(binder.Name) as DelegateObj;
if (theDelegateObj == null || theDelegateObj.CallMethod == null)
{
result = null;
return false;
}
result = theDelegateObj.CallMethod(this,args);
return true;
}
public override bool TryInvoke(InvokeBinder binder, object[] args, out object result)
{
return base.TryInvoke(binder, args, out result);
}
}
public class DynObj : DynamicObject
{
//保存對象動態定義的屬性值
private Dictionary<string, object> _values;
public DynObj()
{
_values = new Dictionary<string, object>();
}
/// <summary>
/// 獲取屬性值 www.2cto.com
/// </summary>
/// <param name="propertyName"></param>
/// <returns></returns>
public object GetPropertyValue(string propertyName)
{
if (_values.ContainsKey(propertyName) == true)
{
return _values[propertyName];
}
return null;
}
/// <summary>
/// 設置屬性值
/// </summary>
/// <param name="propertyName"></param>
/// <param name="value"></param>
public void SetPropertyValue(string propertyName,object value)
{
if (_values.ContainsKey(propertyName) == true)
{
_values[propertyName] = value;
}
else
{
_values.Add(propertyName, value);
}
}
/// <summary>
/// 實現動態對象屬性成員訪問的方法，得到返回指定屬性的值
/// </summary>
/// <param name="binder"></param>
/// <param name="result"></param>
/// <returns></returns>
public override bool TryGetMember(GetMemberBinder binder, out object result)
{
result = GetPropertyValue(binder.Name);
return result == null ? false : true;
}
/// <summary>
/// 實現動態對象屬性值設置的方法。
/// </summary>
/// <param name="binder"></param>
/// <param name="value"></param>
/// <returns></returns>
public override bool TrySetMember(SetMemberBinder binder, object value)
{
SetPropertyValue(binder.Name, value);
return true;
}
/// <summary>
/// 動態對象動態方法調用時執行的實際代碼
/// </summary>
/// <param name="binder"></param>
/// <param name="args"></param>
/// <param name="result"></param>
/// <returns></returns>
public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result)
{
var theDelegateObj = GetPropertyValue(binder.Name) as DelegateObj;
if (theDelegateObj == null || theDelegateObj.CallMethod == null)
{
result = null;
return false;
}
result = theDelegateObj.CallMethod(this,args);
return true;
}
public override bool TryInvoke(InvokeBinder binder, object[] args, out object result)
{
return base.TryInvoke(binder, args, out result);
}
}
應用測試代碼:
[csharp]
dynamic theObj = new DynObj();
theObj.aaa = "this is a test";//動態屬性
//動態方法，這裡不能沒法定義參數，調用的時候可以是任意多參數，具體參數類型和含義就只能自己去小心處理了.
theObj.show = DelegateObj.Function((s, pms) =>
{
if (pms != null && pms.Length > 0)
{
MessageBox.Show(pms[0].ToString() + ":" + s.aaa);
}
else
{
MessageBox.Show(s.aaa);
}
return null;
}
);
theObj.show("hello");
dynamic theObj = new DynObj();
theObj.aaa = "this is a test";//動態屬性
//動態方法，這裡不能沒法定義參數，調用的時候可以是任意多參數，具體參數類型和含義就只能自己去小心處理了.
theObj.show = DelegateObj.Function((s, pms) =>
{
if (pms != null && pms.Length > 0)
{
MessageBox.Show(pms[0].ToString() + ":" + s.aaa);
}
else
{
MessageBox.Show(s.aaa);
}
return null;
}
);
theObj.show("hello");
雖然看起來上面有點Js定義對象方法的味道,但由於C#是靜態語言,提供的動態模擬機制還是有限.
以上代碼在vs2010,windows 2008 server,框架4.0 上測試OK.
摘自 hawksoft
