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using System;
using System.Linq.Expressions;
using System.Reflection;
namespace Pfz
{
/// <summary>
/// This class allows you to get members from types more safely than using
/// string literals. It only exists because C# does not have fieldinfoof,
/// propertyinfoof and methodinfoof.
/// </summary>
public static class ReflectionHelper
{
/// <summary>
/// Gets a member by it's expression usage.
/// For example, GetMember(() => obj.GetType()) will return the
/// GetType method.
/// </summary>
public static MemberInfo GetMember<T>(Expression<Func<T>> expression)
{
if (expression == null)
throw new ArgumentNullException("expression");
var body = expression.Body;
switch(body.NodeType)
{
case ExpressionType.MemberAccess:
MemberExpression memberExpression = (MemberExpression)body;
return memberExpression.Member;
case ExpressionType.Call:
MethodCallExpression callExpression = (MethodCallExpression)body;
return callExpression.Method;
case ExpressionType.New:
NewExpression newExpression = (NewExpression)body;
return newExpression.Constructor;
}
throw new ArgumentException("expression.Body must be a member or call expression.", "expression");
}
/// <summary>
/// Gets a property from a sample usage.
/// Example: GetProperty(() => str.Length) will return the property info
/// of Length.
/// </summary>
public static PropertyInfo GetProperty<T>(Expression<Func<T>> expression)
{
return (PropertyInfo)GetMember(expression);
}
/// <summary>
/// Gets a field from a sample usage.
/// Example: GetField(() => Type.EmptyTypes) will return the FieldInfo of
/// EmptyTypes.
/// </summary>
public static FieldInfo GetField<T>(Expression<Func<T>> expression)
{
return (FieldInfo)GetMember(expression);
}
/// <summary>
/// Gets a method info of a void method.
/// Example: GetMethod(() => Console.WriteLine("")); will return the
/// MethodInfo of WriteLine that receives a single argument.
/// </summary>
public static MethodInfo GetMethod(Expression<Action> expression)
{
if (expression == null)
throw new ArgumentNullException("expression");
var body = expression.Body;
if (body.NodeType != ExpressionType.Call)
throw new ArgumentException("expression.Body must be a Call expression.", "expression");
MethodCallExpression callExpression = (MethodCallExpression)body;
return callExpression.Method;
}
/// <summary>
/// Gets the MethodInfo of a method that returns a value.
/// Example: GetMethod(() => Console.ReadLine()); will return the method info
/// of ReadLine.
/// </summary>
public static MethodInfo GetMethod<T>(Expression<Func<T>> expression)
{
return (MethodInfo)GetMember(expression);
}
/// <summary>
/// Gets the constructor info from a sample construction call expression.
/// Example: GetConstructor(() => new Control()) will return the constructor
/// info for the default constructor of Control.
/// </summary>
public static ConstructorInfo GetConstructor<T>(Expression<Func<T>> expression)
{
return (ConstructorInfo)GetMember(expression);
}
}
}
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I started to program computers when I was 11 years old, as a hobbyist, programming in AMOS Basic and Blitz Basic for Amiga.
At 12 I had my first try with assembler, but it was too difficult at the time. Then, in the same year, I learned C and, after learning C, I was finally able to learn assembler (for Motorola 680x0).
Not sure, but probably between 12 and 13, I started to learn C++. I always programmed "in an object oriented way", but using function pointers instead of virtual methods.
At 15 I started to learn Pascal at school and to use Delphi. At 16 I started my first internship (using Delphi). At 18 I started to work professionally using C++ and since then I've developed my programming skills as a professional developer in C++ and C#, generally creating libraries that help other developers do their work easier, faster and with less errors.
Want more info or simply want to contact me?
Take a look at:
http://paulozemek.azurewebsites.net/
Or e-mail me at: paulozemek@outlook.com
Codeproject MVP 2012, 2015 & 2016
Microsoft MVP 2013-2014 (in October 2014 I started working at Microsoft, so I can't be a Microsoft MVP anymore).