// Invoke method using reflection
public static string InvokeAnalyseMood(string methodName, string message)
{
try
{
// First an instance of MoodAnalyzer is created with the help of reflection
MoodAnalyzer moodAnalyzer = (MoodAnalyzer)MoodAnalyzerReflection.CreateMoodAnalyzerObject("MoodAnalyzerProblem.MoodAnalyzer", "MoodAnalyzer", message);
// Meta information of MoodAnalyzer
var moodAnalyzerType = typeof(MoodAnalyzer);
// Meta information of methodName provided in arguments while calling this function
//GetMethod Returns an object that represents the public method with the specified name, if found; otherwise, null.
var analyseMoodMethod = moodAnalyzerType.GetMethod(methodName);
// Now invoke method using meta information of method, need an instance of class and parameters as arguments
var mood = analyseMoodMethod.Invoke(moodAnalyzer, null);
return(mood.ToString());
}
catch (NullReferenceException)
{
// Get methods returns null incase no method is found with given methodName
// Invoke method will throw exception
throw new MoodAnalyzerException(MoodAnalyzerException.ExceptionType.NO_SUCH_METHOD, "No such method exist!");
}
catch (TargetInvocationException ex)
{
// When message is null or empty this exception is thrown
throw ex.InnerException;
}
}
static void Main(string[] args)
{
try
{
///Change Field With Reflection
MoodAnalyzer moodAnalyzer = new MoodAnalyzer("I am in sad mood!"); //This instance can also be created with Reflection
Console.WriteLine($"Initial Mood was {moodAnalyzer.AnalyseMood()}!");
string newMessage = "I am in happy mood!";
moodAnalyzer = (MoodAnalyzer)MoodAnalyzerReflection.SetField(moodAnalyzer, "message", newMessage);
Console.WriteLine($"New Mood is {moodAnalyzer.AnalyseMood()}!");
}
catch (MoodAnalyzerException ex)
{
Console.WriteLine(ex.Message);
}
}
public static object SetField(MoodAnalyzer moodAnalyzer, string fieldName, string newMessage)
{
try
{
// Meta information of MoodAnalyzer
var moodAnalyzerType = typeof(MoodAnalyzer);
// Meta information of messageField
//GetField Returns an object that represents the field with the specified name, if found; otherwise, null.
var messageField = moodAnalyzerType.GetField(fieldName, BindingFlags.NonPublic | BindingFlags.Instance);
messageField.SetValue(moodAnalyzer, newMessage);
return(moodAnalyzer);
}
catch (NullReferenceException)
{
// GetField returns null incase no field is found with given fieldName
// SetValue method will throw exception
throw new MoodAnalyzerException(MoodAnalyzerException.ExceptionType.NO_SUCH_METHOD, "No such method exist!");
}
}
/// <summary>
/// creating Sets the field.
/// </summary>
/// <param name="message">The message contain happy.</param>
/// <param name="fieldName">Name of the field that is message.</param>
/// <returns>message of mood analyzer class</returns>
/// <exception cref="MoodAnalyzerException">
/// Message should not be null
/// or
/// Field is not found
/// </exception>
public static string SetField(string message, string fieldName)
{
try
{
MoodAnalyzer moodAnalyzer = new MoodAnalyzer();
Type type = typeof(MoodAnalyzer);
FieldInfo field = type.GetField(fieldName, BindingFlags.Public | BindingFlags.Instance);
if (message == null)
{
throw new MoodAnalyzerException(MoodAnalyzerException.ExceptionType.NO_SUCH_FIELD, "Message should not be null");
}
field.SetValue(moodAnalyzer, message);
return(moodAnalyzer.message);
}
catch (NullReferenceException)
{
throw new MoodAnalyzerException(MoodAnalyzerException.ExceptionType.NO_SUCH_FIELD, "Field is not found");
}
}
/* UC7:- Use Reflection to change mood dynamicall
* - User Reflector to Modify mood dynamically
*/
//public static string SetField(string message, string fieldName)
//{
// MoodAnalyzerFactory Fact = new MoodAnalyzerFactory();
// MoodAnalyzer obj = (MoodAnalyzer)Fact.CreateMoodAnalyzerObject("MoodAnalyzerProblem.MoodAnalyzer", "MoodAnalyzer");
// Type type = typeof(MoodAnalyzer);
// FieldInfo field = type.GetField(fieldName, BindingFlags.Public | BindingFlags.Instance);
// if (field!= null)
// {
// if (message==null)
// {
// throw new MoodAnalyzerException(MoodAnalyzerException.ExceptionType.NULL_MESSAGE, "Message should not be null");
// }
// field.SetValue(obj, message);
// return obj.message;
// }
// throw new MoodAnalyzerException(MoodAnalyzerException.ExceptionType.FIELD_NULL, "FieldName should not be null");
//}
/* UC7:- Use Reflection to change mood dynamically
* - User Reflector to Modify mood dynamicall
*/
public static string SetField(string message, string fieldName)
{
try
{
if (message == null)
{
throw new MoodAnalyzerException(MoodAnalyzerException.ExceptionType.NULL, "Mood should not be NULL");
}
MoodAnalyzer obj = new MoodAnalyzer();
Type type = Type.GetType("MoodAnalyzerProblem.MoodAnalyzer");
FieldInfo field = type.GetField(fieldName);
field.SetValue(obj, message);
return(obj.message);
}
catch (NullReferenceException)
{
throw new MoodAnalyzerException(MoodAnalyzerException.ExceptionType.NO_SUCH_FIELD, "No Such Field");
}
}
