Reflection
To read method, prop, construtor, etc from assembly.
We can create assembly at run time
When we use c# dll in vb, and two variables a and A can also be used using reflection
Create new class liabrary (new project in c#)
Public class class1
{
Private int32 eno , es;
Private string en,ed;
Public class1()
{
}
Public class1 ( int32 a, string b, string c, int32 d)
{
Eno = a; ed= c; en=b; es = d;
}
Public int32 p_empno
{
Get
{
Return eno;
}
Set
{
Eno =value;
}
}
Public string p_ename
{
Get
{
Return en;
}
Set
{
En =value;
}
}
Public string p_eadd
{
Get
{
Return ed;
}
Set
{
Ed =value;
}
}
Public int32 p_esal
{
Get
{
Return es;
}
Set
{
Es = value;
}
}
Public int32 callall()
{
Return p_sal * 10 /100;
}
Public int32 calded(int32 pf, int32 tax)
{
Return p_esal * pf/100 + p_esal * tax / 100;
}
}
Compile this class file
Create new web site in c#
Default.aspx;
Code
Using System.reflection;
Type typ = null;
Pageload()
{
Assembly asm = assembly.loadfile(“d:\\classliabrary24 \\classlibrary24\\bin\\debug\\classlibrary24.dll”); //path of dll file
Type[] typs = asm.gettypes; //element of class may be more than one
Typ = asm.gettype(typs[0].tostring());
}
Design
Button1 button2 button3 button4
Button1()
{
Constructorinfo[] ci = typ.getconstructors();
//all constructors in class lib
Int32 I;
For(i=0; i<>
{
Response.write(ci[i].tostring() + “
”);
}
}
Button2()
{
Propertyinfo[] pi = typ.getproperty();
Int32 I;
For(i=0;i
{
Resoponse.write(pi[i].tostring() + “
”);
}
}
Button3()
{
Methodinfo[] mi = typ.getmethods();
Int32 I;
For(i=0;i
{
Response.write(mi[i].tostring() + “
”);
}
}
Button4()
{
Constructorinfo[] ci = typ.getconstructors();
Object obj = activator.createinstance(typ);
//Ci[0].invoke(obj,null); //calling default constructor
Object[] ar = new object[4];
Ar[0] = 10;
Ar[1]=”vikas”;
Ar[2]=”#2223”;
Ar[3]=12000;
Ci[1].invoke(obj,ar);
Propertyinfo[] pi = typ.getproperties();
Response.write(pi[0].getvalue(obj,null).tostring() + “
”);
//to read from property getvalue used
Response.write(pi[1].getvalue(obj,null).tostring() + “
”);
Response.write(pi[2].getvalue(obj,null).tostring() + “
”);
}
Add one more button5
Button5()
{
Propertyinfo[] pi = typ.getproperties();
Object obj = activator.createinstanse(typ);
Pi[0].setvalue(obj,101,null);
Pi[1].setvalue(obj,”aman”,null);
Pi[2].setvalue(obj,”#23adsf”,null);
Pi[3].setvalue(obj,23000,null);
Methodinfo[] mi = typ.getmethods();
Int32 k = (int32)(mi[8].invoke(obj,null));
Response.write(k.tostring() + “
”);
Object[] ar = new object[2];
Ar[0]=20;
Ar[1]=30;
Int32 k1 (int32)(mi[9].invoke(obj,ar));
Response.write(k1.tostring());
}
Add new page:
--------------
Default2.aspx:
Textbox1 Button1
Code:
Using system.reflection;
Using system.reflection.emit;
//emit namespace is used for
Pageload()
{
}
Private assembly abc()
{
Assemlyname nam = new assemblyname();
Nam.name = “myfirstasm”;
Assemblybuilder asmbul = appdomain.currentdomain. definedynamicassembly(nam,assemblybuilderaccess.runandsave,”e:\\abc”);
//current area of app where it is running
//assemblybuilderaccess is used for the type of assmb at runtime, run save or both
//very useful for security purpose
Modulebuilder modbul = asmbul.definedynamicmodule (“myfirstasm”,”myfirstasm.dll”);
// for making namespace
Typebuilder typbul = modbul.definetype(“clsabc”,typeattributes.public | typeattributes.class);
//for making class
Type[] ar = new type[]{typeof(int32),typeof(int32)};
//prototype of a method
Methodbuilder metbul = typbul.definemethod(“sum”,methodattribute.public, typeof(int32), ar);
// for making runtime method
Parameterbuilder p1 = metbul.defineparameter(1, parameterattributes.in, “n1”);
Parameterbuilder p2 = metbul.defineparameter(2, parameterattributes.in, ”n2”);
Ilgenerator ilgen = metbul.getilgenerator();
//for generating msil
Ilgen.emit(opcodes.lgarg_1);
//ldarg_1 stores in stack
Ilgen.emit(opcodes.ldarg_2);
Ilgen.emit(opcodes.add);
Ilgen.emit(opcodes.ret);
Typbul.createtype();
Asmbul.save(“myfirstasm.dll”);
Return asmbul;
}
Button1()
{
Assembly asm = abc();
Type typ = asm.gettype(“clsabc”);
Object obj = activator.createinstance(typ);
Object[] ar = new object[2];
Ar[0]=350;
Ar[1]=500;
Int32 k = (int32) ( typ.invokemember(“sum”,bindingflags.invokemethod,null, obj, ar);
//name of method, invoking method, overloading situation, object name, parametr
Textbox1.text = k.tostring();
}
