使用ef，有时候会遇到，要对一个对象进行拷贝复制，可是一般的方法，拷贝后会提示此对象的实例在上下文的 entitystate已经存在，就需要用一种拷贝。
简单的拷贝只拷贝了值类型，对引用类型的拷贝需要使用递归，依次循环到底。
public object Copy(object obj) {
Object targetDeepCopyObj;
try {
Type targetType = obj.GetType();
//值类型
if (targetType.IsValueType == true) {
targetDeepCopyObj = obj;
}
//引用类型
else {
targetDeepCopyObj = System.Activator.CreateInstance(targetType); //创建引用对象
System.Reflection.MemberInfo[] memberCollection = obj.GetType().GetMembers();
foreach (System.Reflection.MemberInfo member in memberCollection) {
if (member.MemberType == System.Reflection.MemberTypes.Field) {
System.Reflection.FieldInfo field = (System.Reflection.FieldInfo)member;
Object fieldValue = field.GetValue(obj);
if (fieldValue is ICloneable) {
field.SetValue(targetDeepCopyObj, (fieldValue as ICloneable).Clone());
} else {
field.SetValue(targetDeepCopyObj, Copy(fieldValue));
}
} else if (member.MemberType == System.Reflection.MemberTypes.Property) {
System.Reflection.PropertyInfo myProperty = (System.Reflection.PropertyInfo)member;
MethodInfo info = myProperty.GetSetMethod(false);
if (info != null) {
object propertyValue = myProperty.GetValue(obj, null);
if (propertyValue is ICloneable) {
myProperty.SetValue(targetDeepCopyObj, (propertyValue as ICloneable).Clone(), null);
} else {
myProperty.SetValue(targetDeepCopyObj, Copy(propertyValue), null);
}
}
}
}
}
return targetDeepCopyObj;
} catch (Exception e) {
}
return null;
}