Calling a variable with a variable

Michael Mortensen

So I posted the same question but with calling a label with a variable
(http://www.c-sharpcorner.com/Forums/Thread/246996/)

Now I need to call a variable with a variable.
I've tried to modify the code given in the before mentioned thread, but with no luck.
So my question, can it be done? And if so, how?

Saying I have a variable called Cookie, I need to call the variable that equals what is written in the Cookie variable.
Say, Cookie = "Cake"; I would wanna call the Cake variable.

As mentioned I've tried modifying the code given to the label question (thread as mentioned before), but it didn't work. Here's the code I tried:

String TheLabel = (String)this.Controls[cookie];

Please help, I will love you forever if you do :)

3 Replies

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Vulpes12y ago
I was trying to illustrate that the first variable could contain the name of any other variable, either "cake" or "drink" in this example.

To write to a variable, you'd then need to assign a new string to it (as you normally would) and then refresh the dictionary value as well:

static void Main()
{
string cake = "gateau";
string drink = "pepsi";

var dict = new Dictionary
{
{"cake", cake},
{"drink", drink}
};

string cookie = "cake";
Console.WriteLine(dict[cookie]); // gateau
cake = "battenberg"; // write to variable
dict[cookie] = cake; // refresh dictionary value
Console.WriteLine(dict[cookie]); // battenberg
Console.ReadKey();
}
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Michael Mortensen12y ago
It's a local variable. But I don't understand the coding at all.
Why do I need the drink?

Why do I need to chnge Cookie twice?
string cookie = "cake";
Console.WriteLine(dict[cookie]); // gateau
cookie = "drink";
Console.WriteLine(dict[cookie]); // drink

and how do I write to the variable?
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Vulpes12y ago
It depends whether they're local variables or class-level variables.

If they're local variables, you'd need to build some sort of dictionary. For example:

using System;
using System.Collections.Generic;

class Test
{
static void Main()
{
string cake = "gateau";
string drink = "pepsi";

var dict = new Dictionary
{
{"cake", cake},
{"drink", drink}
};

string cookie = "cake";
Console.WriteLine(dict[cookie]); // gateau
cookie = "drink";
Console.WriteLine(dict[cookie]); // drink
Console.ReadKey();
}
}

A similar approach would also work for class-level variables (or fields) though you could also use reflection as well.

using System;
using System.Collections.Generic;
using System.Reflection;

class Test
{
string cake = "gateau";
string drink = "pepsi";

Dictionary dict;

static void Main()
{
Test t = new Test();
t.dict = new Dictionary
{
{"cake", t.cake},
{"drink", t.drink}
};
string cookie = "cake";
Console.WriteLine(t.dict[cookie]); // gateau
cookie = "drink";
Console.WriteLine(t.dict[cookie]); // drink
Console.WriteLine();

// alternatively using reflection
BindingFlags bf = BindingFlags.Instance | BindingFlags.NonPublic;
Type tt = typeof(Test);
cookie = "cake";
Console.WriteLine(tt.GetField(cookie, bf).GetValue(t));// gateau
cookie = "drink";
Console.WriteLine(tt.GetField(cookie, bf).GetValue(t));// drink
Console.ReadKey();
}
}


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