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What is syntax for creating a class in C# that would be equal to a Module in VB.net

I do almost all of my programming in VB.net (all flavors). I am now been assigned a task to make a new routine in an existing C# application. What I want to be able to do is pass a string variable to a class where I can figure out device type of a symbol handheld and figure out where an executable resides on device.
I am trying to keep the class to contain changes we make going forward in one place.
so a brief description is on a screen there will be a button. on that button click I want pass the text of the button to a (what would be a module in VB) a class and depending on text being passed and device type call a separate executable that lives on the device.
Everything I have tried so far has thrown errors.
On my button click i have
String Reponse = clsCallAction("Activity");
but that gets a message that clsCallAction is a type but is used like a variable.
here is the smaple of clsCallaction
internal static partial class clsCallAction
{
public static object GetPath(object lAppName)
{
string resp = "";
if (lAppName.Equals("Activity"))
{
resp = #"\application\activity.exe";
}
return resp;
}
}
If I put new in front of the clsCallAction("Activity") on button click I get a
cannot create instance of the static class 'clsCalACtion'
appreciate any pointers. very new at C#

It would look something like this:
public static class CallAction
{
public static object GetPath(object lAppName)
{
string resp = "";
if (lAppName.Equals("Activity"))
{
resp = #"\application\activity.exe";
}
return resp;
}
}
And would be used like this:
String Reponse = CallAction.GetPath("Activity");
Don't prefix classes with cls
Avoid using object if possible - it just makes everything harder work than it needs to be.. Kinda like calling everything "thing" - ("Put the thing in the thing and open the thing" is harder to understand than "put the key in the lock and open the door")

translating to c# code the use of a class method trough an object variable

I have just two years I started programming (mostly C#), but there's still a lot I don´t know about the language, I'm trying to translate a web project from VB.NET code to C# code, but I got to a section which I don't know how to translate.
The class in the VB code uses a sub procedure to do an INSERT to a database, to do this, in the class there is a db variable declared as an Object, then the db variable uses a function from a module to change the class type depending on the conection type and database is going to be used (this is determined from getting a value from the Web.config file), then after building the query, the db variable uses another function from the new class type assigned to execute the query.
To better ilustrate, here is the VB code.
This is the part where the db variable is used:
Public class MyClass1
Private Sub _AddDB()
Dim db As Object
Dim query As String
db = TypeDB()
query = "Some Query"
db.ExecuteDB(query)
End Sub
End Class
As I said, the TypeDB() function is in a Module:
Module MyModule
Public Function TypeDB() As Object
Dim Str As String = ConfigurationSettings.AppSettings.GetValues("strConnDB").GetValue(0)
Dim db As Object
Select Case Str
Case "SQL"
db = New DBSql_Class
Case "ODBC"
db = New DBOdbc_Class
Case "OLE"
db = New DBOle_Class
End Select
TypeDB = db
End Function
End Module
Each of the classes mentioned on the module has its own ExecuteDB function so there is no problems in executing the line db.ExecuteDB(query). I read that the closest thing to a Module in C# is a static class, so that was what I did with MyModule, I already have the rest of the classes, but when I try:
public class MyClass1
{
private void _AddDB()
{
object db;
string query;
db = MyModuleClass.TypeDB();
query = "Some Query";
db.ExecuteDB(query);
}
}
I immediately get the error that the db objetc does not contain a definition for the method ExecuteDB.
My first idea was to do a switch statement inside the _AddDB method, but it will not be optimal, because there is already a switch statement in the MyModuleClass to select the new type of class for the db variable, I tried searching for a solution, but all I found was only solutions that only uses one class.
I want to do this as close to the original project as posible, but this kind of interaction is all over the VB project.

Object-oriented clean solution to this problem in C# is to define an interface with ExecuteDB() operation and implement it in those three DB classes. Then return that interface from your static method, and then you can call it directly.
interface IDatabase {
object ExecuteDB(string);
}
class DBSql_Class : IDatabase {
public object ExecuteDB(string query) {
...
}
}
static class MyModuleClass {
public static IDatabase TypeDB() {
switch(...) {
...
return new DBSql_Class();
...
}
}
}
Just a note: your class names are terrible. Please try to follow standard naming scheme when programming in .NET. :-)

You need to declare 'db' as dynamic in C# to achieve the same sort of late-binding that the VB code is doing.
e.g.,
dynamic db = null;
string query = null;
db = MyModule.TypeDB();
query = "Some Query";
db.ExecuteDB(query);
Or, better yet, use the appropriate types instead of 'object'.

Evaluating nested property calls from a string

I am currently reading the "500 Lines or Less" book, the chapter for creating a Template Engine from Ned Batchelder.
Their example is using Python. In their template engine they are building code as a string and then they are calling exec (docs) to evaluate the string as Python code.
def get_globals(self):
"""Execute the code, and return a dict of globals it defines."""
# A check that the caller really finished all the blocks they started.
assert self.indent_level == 0
# Get the Python source as a single string.
python_source = str(self)
# Execute the source, defining globals, and return them.
global_namespace = {}
exec(python_source, global_namespace)
return global_namespace
This is very convenient, because they can easily evaluate expressions in the template such as {{object.property.property}}
With C# as my main programming language I am wondering how can this be achieved (in the context of building a template engine as in the book)?
Research and thoughts
First I don't believe there is an exec equivalent in C#.
One way I can think of it is to recursively use Reflection to get the List of properties of an object (handling checks for Null References), but I don't like this from performance point of view.
Another way is to use Roslyn's ScriptEngine class (which I haven't used so correct me if I am wrong). But I am afraid that this won't be good because this is supposed to be a library and it won't be able to be used with older versions of C# and .NET. Example

Q: First I don't believe there is an exec equivalent in C#.
As for compling C# code, CS-Script library can be used to achieve this in various ways.
For example:
dynamic script = CSScript.Evaluator
.LoadCode(#"using System;
using Your.Custom.Relevant.Namespace;
public class Executer
{
public object Execute()
{
return SomeStaticClass.array[123];
}
}");
int result = script.Execute();
//shorter way
int a = (int)CSScript.Evaluator.Evaluate("some.namespace.SomeStaticClass.array[123]");
Read more here: http://www.csscript.net/
CS-Script isn't made for templating.
Unless you create it yourself by manipulating the strings before you compile them.
But how can I pass some Context for the template engine
You can pass a context into a function like this:
dynamic script = CSScript.Evaluator
.LoadCode(#"
using System;
using Namespace.Of.The.Context;
public class Executer {
public string Execute(Context ctx) {
return ctx.Person.Firstname + ctx.Person.Lastname;
}
}");
int result = script.Execute(new Context(new Person("Rick", "Roll")));
Q: Can I call CSScript from a normal C# application lets say a Web App?
A: Yes.
S-Script currently targets Microsoft implementation of CLR (.NET
2.0/3.0/3.5/4.0/4.5) with full support on Mono.
Basically if it runs C#, it can be compiled accordingly to the .net-framework that the library is executed on, so if your project is ran on .net4.5, any feature of that .net version is available including any external references in your project too.

You can use Microsoft.CSharp.CSharpCodeProvider in order to compile code on fly.
https://msdn.microsoft.com/en-us/library/microsoft.csharp.csharpcodeprovider.aspx
Like this:
static void Main(string[] args)
{
string source =
#"
namespace Test
{
public class Test
{
public void HelloWorld()
{
System.Console.WriteLine(""Hello World"");
}
}
}
";
var options = new Dictionary<string, string> { {"CompilerVersion", "v3.5"} };
var provider = new CSharpCodeProvider(options);
var compilerParams = new CompilerParameters{GenerateInMemory = true, GenerateExecutable = false };
var results = provider.CompileAssemblyFromSource(compilerParams, source);
var method = results.CompiledAssembly.CreateInstance("Test.Test");
var methodInfo = method.GetType().GetMethod("HelloWorld");
methodInfo.Invoke(method, null);
}

"Use of unassigned local variable" error with an Interface

I'm having trouble with some syntax. I'm not really familiar with interfaces so please excuse my ignorance.
VS2010 is giving me an error at... application.Name = System.AppDomain.CurrentDomain.FriendlyName;
public static void AddApplication(string applicationName = null, string processImageFileName = null)
{
INetFwAuthorizedApplications applications;
INetFwAuthorizedApplication application;
if(applicationName == null)
{
application.Name = System.AppDomain.CurrentDomain.FriendlyName;/*set the name of the application */
}
else
{
application.Name = applicationName;/*set the name of the application */
}
if (processImageFileName == null)
{
application.ProcessImageFileName = System.Reflection.Assembly.GetExecutingAssembly().Location; /* set this property to the location of the executable file of the application*/
}
else
{
application.ProcessImageFileName = processImageFileName; /* set this property to the location of the executable file of the application*/
}
application.Enabled = true; //enable it
/*now add this application to AuthorizedApplications collection */
Type NetFwMgrType = Type.GetTypeFromProgID("HNetCfg.FwMgr", false);
INetFwMgr mgr = (INetFwMgr)Activator.CreateInstance(NetFwMgrType);
applications = (INetFwAuthorizedApplications)mgr.LocalPolicy.CurrentProfile.AuthorizedApplications;
applications.Add(application);
}
I can make that error go away by setting application to null but that causes a run-time null reference error.
Edit:
Here's where I'm adapting the code from. I hope it gives more context
http://blogs.msdn.com/b/securitytools/archive/2009/08/21/automating-windows-firewall-settings-with-c.aspx

You never initialize
application
before using it here:
application.Name = System.AppDomain.CurrentDomain.FriendlyName;
The variable application is defined as:
INetFwAuthorizedApplication application
You need to assign an instance of a class that implements the interface INetFwAuthorizedApplication.
Somewhere there must be one (or probably more) classes in your project that look something like this:
public class SomeClass : INetFwAuthorizedApplication
{
// ...
}
public class AnotherClass : INetFwAuthorizedApplication
{
// ...
}
You need to determine what class you should use (SomeClass, AnotherClass) then assign an appropriate object, e.g. like this:
INetFwAuthorizedApplication application = new SomeClass();

Interfaces are used to describe what an object does, not what it is specifically. To put into "real world" terms, an interface might be like:
ISmallerThanABreadbox with a FitIntoBreadbox() method. I can't ask you to give me "the smaller than a breadbox" ... as that doesn't make any sense. I can only ask you to give me something that "IS smaller than a breadbox". You have to come up with your own object that makes sense to have the interface on it. An apple is smaller than a breadbox, so if you have a breadbox that only holds items smaller than it, an apple is a good candidate for the ISmallerThanABreadbox interface.
Another example is IGraspable with a Hold() method and FitsInPocket bool property. You can ask to be given something that IS graspable that may or may not fit in your pocket, but you can't ask for "the graspable".
Hope that helps...

Mono Cecil - Initializing a local variable

I have the following method:
public void DoSomething()
{
Console.WriteLine("");
}
I want to modify this code with Mono Cecil. I want to create an instance of a custom class within the method:
public void DoSomething()
{
MyClass instance = new MyClass();
Console.WriteLine("");
}
Currently I use the following code:
var constructorInfo = typeof(MyClass).GetConstructor(new Type[] { });
MethodReference myClassConstructor = targetAssembly.MainModule.Import(constructorInfo);
var processor = targetMethod.Body.GetILProcessor();
var firstInstruction = targetMethod.Body.Instructions[1];
var instructions = new List<Instruction>() {
processor.Create(OpCodes.Newobj, myClassConstructor),
processor.Create(OpCodes.Stloc_0)
};
foreach (var instruction in instructions)
{
processor.InsertBefore(firstInstruction, instruction);
}
After applying those changes, the program is invalid and cannot be executed.
If i use 'IL DASM' to look at the generated code the following statement is missing:
.locals init ([0] class [MyAssembly]MyNamespace.MyClass instance)
The rest of the IL is the same, as if I directly compile the full code.
Any ideas what I am doing wrong?

I have not tried it but by looking at the Cecil Source Code you should first create the local variable which is part of your MethodBody.
MethodBody has a Variables collection which can be filled via
body.Variables.Add( new VariableDefinition(typedef) )
Then you need to call processor.Create(xxx,indexto local variable);
That should do the trick. The only thing I did not see yet how you can get a TypeDefinition out from a Type. I think you need to load the assembly into Mono Cecil first before you can use this approach.