Csharp/CSharp Tutorial/Reflection/Parameter

Analyze method parameters using reflection

<source lang="csharp">using System; using System.Reflection;

class MyClass {

 public MyClass(int i, int j) { 
 } 

 public int sum() { 
   return 0; 
 } 

 public bool isBetween(int i) { 
   return false; 
 } 

 public void set(int a, int b) { 
 } 

 public void set(double a, double b) { 
 } 

 public void show() { 
   Console.WriteLine("show"); 
 } 

}

class MainClass {

 public static void Main() { 
   Type t = typeof(MyClass);

   Console.WriteLine("Analyzing methods in " + t.Name);     
   Console.WriteLine(); 

   Console.WriteLine("Methods supported: "); 

   MethodInfo[] mi = t.GetMethods(); 

   // Display methods supported by MyClass. 
   foreach(MethodInfo m in mi) { 
     // Display return type and name. 
     Console.Write("   " + m.ReturnType.Name + 
                     " " + m.Name + "("); 

     // Display parameters. 
     ParameterInfo[] pi = m.GetParameters(); 

     for(int i=0; i < pi.Length; i++) { 
       Console.Write(pi[i].ParameterType.Name + 
                     " " + pi[i].Name); 
       if(i+1 < pi.Length) Console.Write(", "); 
     } 

     Console.WriteLine(")"); 
    
     Console.WriteLine(); 
   } 
 } 

}</source>

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()

Generic parameter information

<source lang="csharp">using System; using System.Collections.Generic; using System.Text; using System.Threading; using System.Reflection; using System.Reflection.Emit; public class MainClass {

   public static void Main()
   {
       PrintTypeParams(typeof(List<>));
       PrintTypeParams(typeof(List<int>));
       PrintTypeParams(typeof(Nullable<>));
   }
   private static void PrintTypeParams(Type t)
   {
       Console.WriteLine(t.FullName);
       foreach (Type ty in t.GetGenericArguments())
       {
           Console.WriteLine(ty.FullName);
           Console.WriteLine(ty.IsGenericParameter);
           if (ty.IsGenericParameter)
           {
               Type[] constraints = ty.GetGenericParameterConstraints();
               foreach (Type c in constraints)
                   Console.WriteLine(c.FullName);
           }
       }
   }

}</source>

System.Collections.Generic.List`1
True
System.Collections.Generic.List`1[[System.Int32, mscorlib, Version=2.0.0.0, Culture=neutral, PublicK
eyToken=b77a5c561934e089]]
System.Int32
False
System.Nullable`1
True
System.ValueType

Invoke method with parameter type int

<source lang="csharp">using System; using System.Reflection;

class MyClass {

 public MyClass(int i) { 
   Console.WriteLine("Constructing MyClass(int). "); 
 } 

 public MyClass(int i, int j) { 
   Console.WriteLine("Constructing MyClass(int, int). "); 
 } 

 public int sum() { 
   return 0; 
 } 

 public bool isBetween(int i) { 
   return false; 
 } 

 public void set(int a, int b) { 
   Console.Write("Inside set(int, int). "); 
 } 

 public void set(double a, double b) { 
   Console.Write("Inside set(double, double). "); 
 } 

 public void show() { 
   Console.WriteLine("Values"); 
 } 

}

class MainClass {

 public static void Main() { 
   Type t = typeof(MyClass); 
   int x; 
   // Find matching constructor. 
   ConstructorInfo[] ci = t.GetConstructors(); 

   for(x=0; x < ci.Length; x++) { 
     ParameterInfo[] pi =  ci[x].GetParameters(); 
     if(pi.Length == 2) break; 
   } 

   if(x == ci.Length) { 
     Console.WriteLine("No matching constructor found."); 
     return; 
   } 
   else 
     Console.WriteLine("Two-parameter constructor found.\n"); 

   // Construct the object.   
   object[] consargs = new object[2]; 
   consargs[0] = 10; 
   consargs[1] = 20; 
   object reflectOb = ci[x].Invoke(consargs);  
 } 

}</source>

Two-parameter constructor found.
Constructing MyClass(int, int).