When dealing with legacy code I find it invaluable to have a way of accessing private internal members to write. Here’s some very handy code that will do just that. And for goo measure, i’ve included some unit tests.
``` c
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///////////////////////////////////////////////////////////////////////////////////////////////////
using System;
using System.Reflection;
using Components.Infrastructure.Common;
namespace Common.ReflectionHelper
{
///
/// Helper class to simplify common reflection tasks.
///
public static class ReflectionHelper
{
///
/// Sets the value of the private static member.
///
public static void SetStaticFieldValue(string fieldName, Type type, T value)
{
FieldInfo field = type.GetField(fieldName, BindingFlags.NonPublic | BindingFlags.Static);
if (field == null)
throw new ArgumentException(string.Format("Could not find the private instance field '{0}'", fieldName));
field.SetValue(null, value);
}
///
/// Sets the value of the private static member.
///
public static void SetStaticFieldValue(string fieldName, string typeName, T value)
{
Type type = Type.GetType(typeName, true);
FieldInfo field = type.GetField(fieldName, BindingFlags.NonPublic | BindingFlags.Static);
if (field == null)
throw new ArgumentException(string.Format("Could not find the private instance field '{0}'", fieldName));
field.SetValue(null, value);
}
///
/// Returns the value of the private member specified.
///
/// Name of the member.
/// Type of the member.
public static T GetStaticFieldValue(string fieldName, Type type)
{
FieldInfo field = type.GetField(fieldName, BindingFlags.NonPublic | BindingFlags.Static);
if (field != null)
{
return (T)field.GetValue(type);
}
return default(T);
}
///
/// Returns the value of the private member specified.
///
/// Name of the member.
///
public static T GetStaticFieldValue(string fieldName, string typeName)
{
Type type = Type.GetType(typeName, true);
FieldInfo field = type.GetField(fieldName, BindingFlags.NonPublic | BindingFlags.Static);
if (field != null)
{
return (T)field.GetValue(type);
}
return default(T);
}
///
/// Sets the value of the private member specified.
///
/// Name of the member.
/// The object that contains the member.
/// The value to set the member to.
public static void SetPrivateInstanceFieldValue(string memberName, object source, object value)
{
FieldInfo field = source.GetType().GetField(memberName, BindingFlags.GetField | BindingFlags.NonPublic | BindingFlags.Instance);
if (field == null)
throw new ArgumentException(string.Format("Could not find the private instance field '{0}'", memberName));
field.SetValue(source, value);
}
///
/// Sets the value of the private member specified.
///
/// Name of the property.
/// The object that contains the property.
/// The value to set the property to.
public static void SetPrivateInstancePropertyValue(string propName, object source, object value)
{
PropertyInfo property = source.GetType().GetProperty(propName, BindingFlags.GetField | BindingFlags.NonPublic | BindingFlags.Instance);
if (property == null)
throw new ArgumentException(string.Format("Could not find the private instance property '{0}'", propName));
property.SetValue(source, value, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.SetProperty | BindingFlags.Instance, null, null, null);
}
///
/// Returns the value of the private member specified.
///
/// Name of the member.
/// The object that contains the member.
public static object GetStaticField(string fieldName, object source)
{
return GetStaticField(fieldName, source, source.GetType());
}
///
/// Returns the value of the private member specified.
///
/// Name of the member.
/// The object that contains the member.
///
public static object GetStaticField(string fieldName, object source, Type type)
{
FieldInfo field = type.GetField(fieldName, BindingFlags.NonPublic | BindingFlags.Static);
if(field != null)
{
return field.GetValue(type);
}
return null;
}
///
/// Returns the value of the private member specified.
///
/// Name of the member.
/// The object that contains the member.
public static object GetPrivateInstanceField(string memberName, object source)
{
FieldInfo field = source.GetType().GetField(memberName, BindingFlags.GetField | BindingFlags.NonPublic | BindingFlags.Instance);
if(field != null)
{
return field.GetValue(source);
}
return null;
}
///
/// Returns the value of the private member specified.
///
/// Name of the member.
/// The object that contains the member.
public static object GetPrivateInstanceProperty(string propName, object source)
{
PropertyInfo prop = source.GetType().GetProperty(propName, BindingFlags.GetProperty | BindingFlags.NonPublic | BindingFlags.Instance);
if (prop != null)
{
return prop.GetValue(source, BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.SetProperty | BindingFlags.Instance, null, null, null);
}
return null;
}
public static object RunStaticMethod(Type t, string strMethod, object[] objParams)
{
BindingFlags eFlags = BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic;
return RunMethod(t, strMethod, null, objParams, eFlags);
}
public static object RunInstanceMethod(Type t, string strMethod, object objInstance, object[] aobjParams)
{
BindingFlags eFlags = BindingFlags.Instance | BindingFlags.Public |
BindingFlags.NonPublic;
return RunMethod(t, strMethod, objInstance, aobjParams, eFlags);
}
private static object RunMethod(Type t, string strMethod, object objInstance, object[] objParams,
BindingFlags eFlags)
{
MethodInfo m = t.GetMethod(strMethod, eFlags);
if (m == null)
{
throw new ArgumentException("There is no method '" + strMethod + "' for type '" + t + "'.");
}
object objRet = m.Invoke(objInstance, objParams);
return objRet;
}
}
}
///////////////////////////////////////////////////////////////////////////////////////////////////
// Unit Test
///////////////////////////////////////////////////////////////////////////////////////////////////
namespace Common.UnitTests.ReflectionHelper {
internal class TestClass
{
private string myField = "This is my initial value"; private String MyProperty
{
get { return myField; }
set { myField = value; }
}
}
[TestFixture]
public class ReflectionHelperTests
{
[Test]
public void PrivateInstanceFieldsTest()
{
var testValue = "This is my new Value";
var myTestClass = new TestClass();
var result = ReflectionHelper.GetPrivateInstanceField("myField", myTestClass);
ReflectionHelper.SetPrivateInstanceFieldValue("myField", myTestClass, testValue);
result = ReflectionHelper.GetPrivateInstanceField("myField", myTestClass);
Assert.AreEqual(testValue, result);
}
[Test]
public void PrivateInstancePropertyTest()
{
var testValue = "This is my new Value";
var myTestClass = new TestClass();
ReflectionHelper.SetPrivateInstancePropertyValue("MyProperty", myTestClass, testValue);
var result = ReflectionHelper.GetPrivateInstanceProperty("MyProperty", myTestClass);
Assert.AreEqual(testValue, result);
}
}
}
```
