C# 方便的复制/比较物件内数据的方法(Object Copy / Compare)

用 Collection / Object 时经常想用一个物件(Object)去生成另一个物件并保留原有数据(如 DataTable.Copy())，最没头没脑的做法是:

public MyObject Copy() { MyObject oNewObject = new MyObject(); oNewObject.Value1 = this.Value1; oNewObject.Value2 = this.Value2; oNewObject.Value3 = this.Value3; return oNewObject; } public bool Compare(MyObject oNewObject) { return (oNewObject.Value1 == this.Value1 && oNewObject.Value2 == this.Value2 && oNewObject.Value3 == this.Value3); }

 

如果每个物件(Object )只有十多个属性(Properties)的话这样只是小菜一碟，但当你有数十个物件...每个物件有数十个属性的话，那就有够脑残了...

以下是用Reflection的PropertyInfo去提取物件属性的例子:

using System.Reflection; . . . for(int i = 0; i < oOldObject.GetType().GetProperties().Length; i ++) { //根据索引提取个别属性 PropertyInfo oOldObjectProperty = (PropertyInfo) oOldObject.GetType().GetProperties().GetValue(i); //得到该属性的数据 Object oOldObjectValue = oOldObjectProperty.GetValue(oOldObject, null); if (oOldObjectProperty.CanRead) { Console.WriteLine(oOldObjectProperty.Name + " = " + oOldObjectValue.ToString()); } }

 

如此便能列出物件中的所有属性，用同样的方法应该就能轻松复制/比较两个物件了:

using System.Reflection; . . . public MyObject Copy() { MyObject oNewObject = new MyObject(); for(int i = 0; i < this.GetType().GetProperties().Length; i ++) { PropertyInfo oOldObjectProperty = (PropertyInfo) this.GetType().GetProperties().GetValue(i); Object oOldObjectValue = oOldObjectProperty.GetValue(this, null); PropertyInfo oNewObjectProperty = (PropertyInfo) oNewObject.GetType().GetProperties().GetValue(i); if (oOldObjectProperty.CanRead) { //设定oNewObject的当前属性的值为oOldObjectValue(数据类型必须(必定)一致) oNewObjectProperty.SetValue(oNewObject, oOldObjectValue, null); } } return oNewObject; } public bool Compare(MyObject oNewObject) { bool bResult = true; for(int i = 0; i < this.GetType().GetProperties().Length; i ++) { PropertyInfo oOldObjectProperty = (PropertyInfo) this.GetType().GetProperties().GetValue(i); Object oOldObjectValue = oOldObjectProperty.GetValue(this, null); PropertyInfo oNewObjectProperty = (PropertyInfo) oNewObject.GetType().GetProperties().GetValue(i); Object oNewObjectValue = oNewObjectProperty.GetValue(oNewObject, null); //防止属性是NULL if (oOldObjectValue != null && oNewObjectValue != null) { switch(oOldObjectProperty.PropertyType.ToString()) { case "System.Double": //Double 会有机会变成如2.49999999...的无限小数, 变成String才准确 bResult = (((double)oOldObjectValue).ToString("0.000000") == ((double)oNewObjectValue).ToString("0.000000")); break; case "System.DateTime": //量度到秒就够了 bResult = (((DateTime)oOldObjectValue).ToString("yyyy/MM/dd HH:mm:ss") == ((DateTime)oNewObjectValue).ToString("yyyy/MM/dd HH:mm:ss")); break; case "System.Boolean": bResult = (((bool)oOldObjectValue) == ((bool)oNewObjectValue)); break; default: bResult = (oOldObjectValue.ToString() == oNewObjectValue.ToString()); break; } } else { //验证个别属性是NULL if (!(oOldObjectValue == null && oOldObjectValue == null)) { bResult = false; } } //如发现有不同就不用再比对了 if (!bResult) { break; } } return bResult; }