c#,reflection

Kerim 8/13/2016 0

These sample codes shows how to use reflections in C#

C#
 [C#]
// create instance of class DateTime
DateTime dateTime = (DateTime)Activator.CreateInstance(typeof(DateTime));

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

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

[C#]
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() { ... }
    }
}

Examples of using reflection to load the Test.dll assembly, to create instance of the Calculator class and to access its members (public/private, instance/static).

[C#]
// dynamically load assembly from file Test.dll
Assembly testAssembly = Assembly.LoadFile(@"c:\Test.dll");

[C#]
// get type of class Calculator from just loaded assembly
Type calcType = testAssembly.GetType("Test.Calculator");

[C#]
// create instance of class Calculator
object calcInstance = Activator.CreateInstance(calcType);

[C#]
// get info about property: public double Number
PropertyInfo numberPropertyInfo = calcType.GetProperty("Number");

[C#]
// get value of property: public double Number
double value = (double)numberPropertyInfo.GetValue(calcInstance, null);

[C#]
// set value of property: public double Number
numberPropertyInfo.SetValue(calcInstance, 10.0, null);

[C#]
// get info about static property: public static double Pi
PropertyInfo piPropertyInfo = calcType.GetProperty("Pi");

[C#]
// get value of static property: public static double Pi
double piValue = (double)piPropertyInfo.GetValue(null, null);

[C#]
// invoke public instance method: public void Clear()
calcType.InvokeMember("Clear",
    BindingFlags.InvokeMethod | BindingFlags.Instance | BindingFlags.Public,
    null, calcInstance, null);

[C#]
// invoke private instance method: private void DoClear()
calcType.InvokeMember("DoClear",
    BindingFlags.InvokeMethod | BindingFlags.Instance | BindingFlags.NonPublic,
    null, calcInstance, null);

[C#]
// 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 });

[C#]
// invoke public static method: public static double GetPi()
double piValue = (double)calcType.InvokeMember("GetPi",
    BindingFlags.InvokeMethod | BindingFlags.Static | BindingFlags.Public,
    null, null, null);

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

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