ParameterBuilder Class

using System;
using System.Threading;
using System.Reflection;
using System.Reflection.Emit;

class Example
{

   public static Type BuildCustomerDataType()
   {

      AppDomain myDomain = Thread.GetDomain();
      AssemblyName myAsmName = new AssemblyName();
      myAsmName.Name = "MyDynamicAssembly";

      AssemblyBuilder myAsmBuilder = myDomain.DefineDynamicAssembly(myAsmName,
                     AssemblyBuilderAccess.Run);

      ModuleBuilder myModBuilder = myAsmBuilder.DefineDynamicModule("MyMod");

      TypeBuilder myTypeBuilder = myModBuilder.DefineType("CustomerData",
                     TypeAttributes.Public);

      FieldBuilder customerNameBldr = myTypeBuilder.DefineField("customerName",
                        typeof(string),
                        FieldAttributes.Private);
      FieldBuilder acctIDBldr = myTypeBuilder.DefineField("acctID",
                        typeof(string),
                        FieldAttributes.Private);
      FieldBuilder balanceAmtBldr = myTypeBuilder.DefineField("balanceAmt",
                        typeof(double),
                        FieldAttributes.Private);

      ConstructorBuilder myCtorBuilder = myTypeBuilder.DefineConstructor(
                        MethodAttributes.Public,
                        CallingConventions.HasThis,
                        new Type[] { typeof(string),
								     typeof(string),
								     typeof(double) });


      ILGenerator ctorIL = myCtorBuilder.GetILGenerator();

      Type objType = Type.GetType("System.Object");
      ConstructorInfo objCtor = objType.GetConstructor(new Type[] { });

      ctorIL.Emit(OpCodes.Ldarg_0);
      ctorIL.Emit(OpCodes.Call, objCtor);

      ctorIL.Emit(OpCodes.Ldarg_0);
      ctorIL.Emit(OpCodes.Ldarg_1);
      ctorIL.Emit(OpCodes.Stfld, customerNameBldr);

      ctorIL.Emit(OpCodes.Ldarg_0);
      ctorIL.Emit(OpCodes.Ldarg_2);
      ctorIL.Emit(OpCodes.Stfld, acctIDBldr);

      ctorIL.Emit(OpCodes.Ldarg_0);
      ctorIL.Emit(OpCodes.Ldarg_3);
      ctorIL.Emit(OpCodes.Stfld, balanceAmtBldr);

      ctorIL.Emit(OpCodes.Ret);

      // This method will take an amount from a static pool and add it to the balance.

      // Note that we are passing the first parameter, fundsPool, by reference. Therefore,
      // we need to inform the MethodBuilder to expect a ref, by declaring the first
      // parameter's type to be System.Double& (a reference to a double).

      MethodBuilder myMthdBuilder = myTypeBuilder.DefineMethod("AddFundsFromPool",
                     MethodAttributes.Public,
                     typeof(double),
                     new Type[] { Type.GetType("System.Double&"),
							     typeof(double) });

      ParameterBuilder poolRefBuilder = myMthdBuilder.DefineParameter(1,
                     ParameterAttributes.Out,
                     "fundsPool");

      ParameterBuilder amountFromPoolBuilder = myMthdBuilder.DefineParameter(2,
                     ParameterAttributes.In,
                          "amountFromPool");

      ILGenerator mthdIL = myMthdBuilder.GetILGenerator();

      mthdIL.Emit(OpCodes.Ldarg_1);
      mthdIL.Emit(OpCodes.Ldarg_1);
      mthdIL.Emit(OpCodes.Ldind_R8);
      mthdIL.Emit(OpCodes.Ldarg_2);
      mthdIL.Emit(OpCodes.Sub);

      mthdIL.Emit(OpCodes.Stind_R8);

      mthdIL.Emit(OpCodes.Ldarg_0);
      mthdIL.Emit(OpCodes.Ldarg_0);
      mthdIL.Emit(OpCodes.Ldfld, balanceAmtBldr);
      mthdIL.Emit(OpCodes.Ldarg_2);
      mthdIL.Emit(OpCodes.Add);

      mthdIL.Emit(OpCodes.Stfld, balanceAmtBldr);

      mthdIL.Emit(OpCodes.Ldarg_0);
      mthdIL.Emit(OpCodes.Ldfld, balanceAmtBldr);
      mthdIL.Emit(OpCodes.Ret);

      return myTypeBuilder.CreateType();

   }

   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      Type custType = null;
      object custObj = null;

      Type[] custArgTypes = new Type[] { typeof(string), typeof(string), typeof(double) };

      // Call the method to build our dynamic class.

      custType = BuildCustomerDataType();

      outputBlock.Text += "---" + "\n";

      ConstructorInfo myCustCtor = custType.GetConstructor(custArgTypes);
      double initialBalance = 100.00;
      custObj = myCustCtor.Invoke(new object[] { "Joe Consumer", 
						   "5678-XYZ", 
					  	   initialBalance });

      MemberInfo[] myMemberInfo = custType.GetMember("AddFundsFromPool");


      double thePool = 1000.00;
      outputBlock.Text += String.Format("The pool is currently ${0}", thePool) + "\n";
      outputBlock.Text += String.Format("The original balance of the account instance is ${0}",
                        initialBalance) + "\n";

      double amountFromPool = 50.00;
      outputBlock.Text += String.Format("The amount to be subtracted from the pool and added " +
              "to the account is ${0}", amountFromPool) + "\n";

      outputBlock.Text += "---" + "\n";
      outputBlock.Text += String.Format("Calling {0} ...", myMemberInfo[0].ToString()) + "\n";
      outputBlock.Text += "---" + "\n";

      object[] passMe = new object[] { thePool, amountFromPool };
      outputBlock.Text += String.Format("The new balance in the account instance is ${0}",
                  custType.InvokeMember("AddFundsFromPool",
                  BindingFlags.InvokeMethod,
                  null, custObj, passMe)) + "\n";
      thePool = (double)passMe[0];
      outputBlock.Text += String.Format("The new amount in the pool is ${0}", thePool) + "\n";

   }

}