Examples of Reflection in C#

// Create instance of class DateTime
DateTime dateTime = (DateTime)Activator.CreateInstance(typeof(DateTime));

// Create instance of DateTime, use constructor with parameters (year, month, day)
DateTime dateTime = (DateTime)Activator.CreateInstance(typeof(DateTime), new object[] { 2008, 7, 4 });

All the following examples try to access to sample class Calculator from Test.dll assembly. The calculator class can be defined like this.

namespace Test
{
    public class Calculator
    {
        public Calculator() { ... }
        private double _number;
        public double Number { get { ... } set { ... } }
        public void Clear() { ... }
        private void DoClear() { ... }
        public double Add(double number) { ... }
        public static double Pi { ... }
        public static double GetPi() { ... }
    }
}

// Dynamically load assembly from file Test.dll
Assembly testAssembly = Assembly.LoadFile(@"c:\Test.dll");

// Get type of class Calculator from just loaded assembly
Type calcType = testAssembly.GetType("Test.Calculator");

// Create instance of class Calculator
object calcInstance = Activator.CreateInstance(calcType);

// Get info about property: public double Number
PropertyInfo numberPropertyInfo = calcType.GetProperty("Number");

// Get value of property: public double Number
double value = (double)numberPropertyInfo.GetValue(calcInstance, null);

// Set value of property: public double Number
numberPropertyInfo.SetValue(calcInstance, 10.0, null);

// Get info about static property: public static double Pi
PropertyInfo piPropertyInfo = calcType.GetProperty("Pi");

// Get value of static property: public static double Pi
double piValue = (double)piPropertyInfo.GetValue(null, null);

// Invoke public instance method: public void Clear()
calcType.InvokeMember("Clear",
    BindingFlags.InvokeMethod | BindingFlags.Instance | BindingFlags.Public,
    null, calcInstance, null);

// Invoke private instance method: private void DoClear()
calcType.InvokeMember("DoClear", BindingFlags.InvokeMethod | BindingFlags.Instance | BindingFlags.NonPublic, null, calcInstance, null);

// Invoke public instance method: public double Add(double number)
double value = (double)calcType.InvokeMember("Add", BindingFlags.InvokeMethod | BindingFlags.Instance | BindingFlags.Public, null, calcInstance, new object[] { 20.0 });

// Invoke public static method: public static double GetPi()
double piValue = (double)calcType.InvokeMember("GetPi",
    BindingFlags.InvokeMethod | BindingFlags.Static | BindingFlags.Public, null, null, null);

// Get value of private field: private double _number
double value = (double)calcType.InvokeMember("_number",
BindingFlags.GetField | BindingFlags.Instance | BindingFlags.NonPublic,
null, calcInstance, null);