bool IsGenericType string Namespace in C#.NET

Encoder Quick Response Code in C#.NET bool IsGenericType string Namespace

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Using Type s methods and properties, it is possible to obtain detailed information about a type at runtime This is an extremely powerful feature, because once you have obtained information about a type, you can invoke its constructors, call its methods, and use its properties Thus, reflection enables you to use code that was not available at compile time The Reflection API is quite large, and it is not possible to cover the entire topic here (Complete coverage of reflection could easily fill an entire book!) However, because the Reflection API is logically designed, once you understand how to use a part of it, the rest just falls into place With this thought in mind, the following sections demonstrate four key reflection techniques: obtaining information about methods, invoking methods, constructing objects, and loading types from assemblies

Once you have a Type object, you can obtain a list of methods supported by the type by using GetMethods( ) One form is shown here: MethodInfo[ ] GetMethods( ) It returns an array of MethodInfo objects that describe the methods supported by the invoking type MethodInfo is in the SystemReflection namespace MethodInfo is derived from the abstract class MethodBase, which inherits MemberInfo Thus, the properties and methods defined by all three of these classes are available for your use For example, to obtain the name of a method, use the Name property Two members that are of particular interest at this time are ReturnType and GetParameters( ) The return type of a method is found in the read-only ReturnType property, which is an object of Type The method GetParameters( ) returns a list of the parameters associated with a method It has this general form: ParameterInfo[ ] GetParameters( ); The parameter information is held in a ParameterInfo object ParameterInfo defines a large number of properties and methods that describe the parameter Two properties that are of particular value are Name, which is a string that contains the name of the parameter, and ParameterType, which describes the parameter s type The parameter s type is encapsulated within a Type object Here is a program that uses reflection to obtain the methods supported by a class called MyClass For each method, it displays the return type and name of the method, and the name and type of any parameters that each method may have

// Analyze methods using reflection using System; using SystemReflection; class MyClass { int x; int y;

Part I:

public MyClass(int i, int j) { x = i; y = j; } public int Sum() { return x+y; } public bool IsBetween(int i) { if(x < i && i < y) return true; else return false; } public void Set(int a, int b) { x = a; y = b; } public void Set(double a, double b) { x = (int) a; y = (int) b; } public void Show() { ConsoleWriteLine(" x: {0}, y: {1}", x, y); } } class ReflectDemo { static void Main() { Type t = typeof(MyClass); // get a Type object representing MyClass ConsoleWriteLine("Analyzing methods in " + tName); ConsoleWriteLine(); ConsoleWriteLine("Methods supported: "); MethodInfo[] mi = tGetMethods(); // Display methods supported by MyClass foreach(MethodInfo m in mi) { // Display return type and name ConsoleWrite(" " + mReturnTypeName + " " + mName + "("); // Display parameters ParameterInfo[] pi = mGetParameters(); for(int i=0; i < piLength; i++) { ConsoleWrite(pi[i]ParameterTypeName + " " + pi[i]Name); if(i+1 < piLength) ConsoleWrite(", "); }

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ConsoleWriteLine(")"); ConsoleWriteLine();

} } }

The output is shown here:

Analyzing methods in MyClass Methods supported: Int32 Sum() Boolean IsBetween(Int32 i) Void Set(Int32 a, Int32 b) Void Set(Double a, Double b) Void Show() Type GetType() String ToString() Boolean Equals(Object obj) Int32 GetHashCode()

Notice that in addition to the methods defined by MyClass, the methods defined by object are also displayed This is because all types in C# inherit object Also notice that the NET structure names are used for the type names Observe that Set( ) is displayed twice This is because Set( ) is overloaded One version takes int arguments The other takes double arguments Let s look at this program closely First, notice that MyClass defines a public constructor and a number of public methods, including the overloaded Set( ) method Inside Main( ), a Type object representing MyClass is obtained using this line of code: