CODEWITHSUNDEEP
c#variablesreflectiontypes
Rosmarine Popcorn
Rosmarine Popcorn

Reputation: 10967

Changing Variable Type on RunTime

Today i had a challenge with my College and i gaved up ,no idea how to achieve it . Is there a way to declare a String ,as Constant and on Load Event maybe using Reflection to change String to non-Constant assign a value from XML ,than Change it to Constant again .

And all of the Code which does that (Constant to Non-Constant),should be Stored in a String ,and on Load before Type Change ,it should be Decrypted and Injected into the Application .

example:

private const String RegNumber = "";
//Change RegNumber to Writable String
//Change RegNumber value
//Than Change RegNumber back to const again

PS : Please sorry but i have no idea where to start ,and show here some code .

Upvotes: 0

Views: 862

Answers (3)

Jon Skeet
Jon Skeet

Reputation: 1500035

You can't declare it as const but you can declare it as static readonly:

private static readonly string Foo = ReadValueFromAssembly();

static string ReadValueFromAssembly()
{
    // Perform your logic and return the string here
}

Would that do everything you need? It's not really clear what you mean about the "code which does that [...] should be decrypted and injected into the application" but you can make the above method do anything you need it to as normal.

As a side-note, it's generally a bad idea to do a lot of work in a type initializer like this.

EDIT: You can store code as a string, use CSharpCodeProvider to compile it at execution time, and then execute the compiled code. I have a sample of this in "Snippy" which I used for C# in Depth as a quick tool for compiling snippets.

Upvotes: 1

Madhur Ahuja
Madhur Ahuja

Reputation: 22661

It is theoratically possible. See

How to programmatically compile code using C# compiler

http://support.microsoft.com/kb/304655

You can write the code in a string and compile using the API mentioned in above article.

I have not done that before but it should give you an idea on how to start.

Also see,

Can I change value of constant in C#?

Upvotes: 0

chrisaut
chrisaut

Reputation: 1086

It may not even exist at runtime, the compiler could have just replaced all usages of it with their literal values (in fact, it probably has, though I don't think it's required to by the standard).

So no, I don't see how this could be possible.

Upvotes: 0

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