是否可以通过反射设置私有财产？

我可否透过反思设定私人物业？

public abstract class Entity
{
private int _id;
private DateTime? _createdOn;
public virtual T Id
{
get { return _id; }
private set { ChangePropertyAndNotify(ref _id, value, x => Id); }
}
public virtual DateTime? CreatedOn
{
get { return _createdOn; }
private set { ChangePropertyAndNotify(ref _createdOn, value, x => CreatedOn); }
}
}

我尝试了以下方法，但是没有用，其中 t代表 Entity的一种类型:

var t = typeof(Entity);
var mi = t.GetMethod("set_CreatedOn", BindingFlags.Instance | BindingFlags.NonPublic);

我想我可以做到这一点，但我不能工作了。

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小开
最佳答案
t.GetProperty("CreatedOn")
.SetValue(obj, new DateTime(2009, 10, 14), null);

编辑: 由于该属性本身是公共的，显然不需要使用 BindingFlags.NonPublic来找到它。调用 SetValue，尽管设置器具有较少的可访问性仍然做您期望的事情。

小开

是的:

/// <summary>
/// Returns a _private_ Property Value from a given Object. Uses Reflection.
/// Throws a ArgumentOutOfRangeException if the Property is not found.
/// </summary>
/// <typeparam name="T">Type of the Property</typeparam>
/// <param name="obj">Object from where the Property Value is returned</param>
/// <param name="propName">Propertyname as string.</param>
/// <returns>PropertyValue</returns>
public static T GetPrivatePropertyValue<T>(this object obj, string propName)
{
if (obj == null) throw new ArgumentNullException("obj");
PropertyInfo pi = obj.GetType().GetProperty(propName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
if (pi == null) throw new ArgumentOutOfRangeException("propName", string.Format("Property {0} was not found in Type {1}", propName, obj.GetType().FullName));
return (T)pi.GetValue(obj, null);
}


/// <summary>
/// Returns a private Property Value from a given Object. Uses Reflection.
/// Throws a ArgumentOutOfRangeException if the Property is not found.
/// </summary>
/// <typeparam name="T">Type of the Property</typeparam>
/// <param name="obj">Object from where the Property Value is returned</param>
/// <param name="propName">Propertyname as string.</param>
/// <returns>PropertyValue</returns>
public static T GetPrivateFieldValue<T>(this object obj, string propName)
{
if (obj == null) throw new ArgumentNullException("obj");
Type t = obj.GetType();
FieldInfo fi = null;
while (fi == null && t != null)
{
fi = t.GetField(propName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
t = t.BaseType;
}
if (fi == null) throw new ArgumentOutOfRangeException("propName", string.Format("Field {0} was not found in Type {1}", propName, obj.GetType().FullName));
return (T)fi.GetValue(obj);
}


/// <summary>
/// Sets a _private_ Property Value from a given Object. Uses Reflection.
/// Throws a ArgumentOutOfRangeException if the Property is not found.
/// </summary>
/// <typeparam name="T">Type of the Property</typeparam>
/// <param name="obj">Object from where the Property Value is set</param>
/// <param name="propName">Propertyname as string.</param>
/// <param name="val">Value to set.</param>
/// <returns>PropertyValue</returns>
public static void SetPrivatePropertyValue<T>(this object obj, string propName, T val)
{
Type t = obj.GetType();
if (t.GetProperty(propName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance) == null)
throw new ArgumentOutOfRangeException("propName", string.Format("Property {0} was not found in Type {1}", propName, obj.GetType().FullName));
t.InvokeMember(propName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.SetProperty | BindingFlags.Instance, null, obj, new object[] { val });
}


/// <summary>
/// Set a private Property Value on a given Object. Uses Reflection.
/// </summary>
/// <typeparam name="T">Type of the Property</typeparam>
/// <param name="obj">Object from where the Property Value is returned</param>
/// <param name="propName">Propertyname as string.</param>
/// <param name="val">the value to set</param>
/// <exception cref="ArgumentOutOfRangeException">if the Property is not found</exception>
public static void SetPrivateFieldValue<T>(this object obj, string propName, T val)
{
if (obj == null) throw new ArgumentNullException("obj");
Type t = obj.GetType();
FieldInfo fi = null;
while (fi == null && t != null)
{
fi = t.GetField(propName, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
t = t.BaseType;
}
if (fi == null) throw new ArgumentOutOfRangeException("propName", string.Format("Field {0} was not found in Type {1}", propName, obj.GetType().FullName));
fi.SetValue(obj, val);
}
小开

可以通过代码从派生类型访问私有 setter

public static void SetProperty(object instance, string propertyName, object newValue)
{
Type type = instance.GetType();


PropertyInfo prop = type.BaseType.GetProperty(propertyName);


prop.SetValue(instance, newValue, null);
}
小开 
    //mock class
public class Person{
public string Name{get; internal set;}
}


// works for all types, update private field through reflection
public static T ReviveType<T>(T t, string propertyName, object newValue){
// add a check here that the object t and propertyName string are not null
PropertyInfo pi = t.GetType().GetProperty(propertyName, BindingFlags.Public | BindingFlags.Instance);
pi.SetValue(t, newValue, null);
return t;
}


// check the required function
void Main()
{
var p = new Person(){Name="John"};
Console.WriteLine("Name: {0}",p.Name);


//box the person to object, just to see that the method never care about what type you pass it
object o = p;
var updatedPerson = ReviveType<Object>(o, "Name", "Webber") as Person;


//check if it updated person instance
Console.WriteLine("Name: {0}",updatedPerson.Name);
}






// Console Result: -------------------
Name: John
Name: Webber
小开

这些都不适合我，而且我的属性名是唯一的，所以我只使用了这个:

public static void SetPrivatePropertyValue<T>(T obj, string propertyName, object newValue)
{
// add a check here that the object obj and propertyName string are not null
foreach (FieldInfo fi in obj.GetType().GetFields(BindingFlags.Instance | BindingFlags.NonPublic))
{
if (fi.Name.ToLower().Contains(propertyName.ToLower()))
{
fi.SetValue(obj, newValue);
break;
}
}
}
小开

使用

            UtilTest.SetProperty(data.Process, "CurrentStepId", (int)WorkFlowStep.HappyClaimsIsContract);

定义

public class UtilTest
{
public static void SetProperty( object instance, string propertyName, object newValue)
{
try
{
Type type = instance.GetType();


PropertyInfo prop = type.GetProperty(propertyName);
if (prop.PropertyType == typeof(decimal))
{
prop.SetValue(instance, Convert.ToDecimal(newValue), null);


}
else
{
prop.SetValue(instance, newValue, null);
}
}
catch
{
}


}

}


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