How to dynamically set variable value with C#?

Question

For example, PHP code:

$test = "hello";
${$test} = $test;
echo $hello; // return hello

How to do this in C#? Thanks in advance.

UPD: Dynamic variable in C#? - here is an answer.

your example doesn't make much sense to me, care to clarify? — BrokenGlass, Oct 01 '11 at 15:36
How to dynamically set variable name perhaps? Answered here: http://stackoverflow.com/questions/1282888/dynamic-variable-in-c — jk., Oct 01 '11 at 15:37
@BrokenGlass: In PHP, if `$test = 'foo'`, then `${$test}` accesses `$foo`. — C. K. Young, Oct 01 '11 at 15:38
is the important part to create a new variable named like a string ? — Yahia, Oct 01 '11 at 15:38

Ahmad Mageed · Accepted Answer · 2011-10-01T15:43:24.310

This isn't supported in C#. You could use an ExpandoObject and set a member on it, but it's not quite the same as the PHP code. You'll still need to refer to the ExpandoObject by a variable name.

dynamic myObject = new ExpandoObject();
string test = "Hello";
((IDictionary<string, object>)myObject).Add(test, test);
Console.WriteLine(myObject.Hello);

Nonetheless, this doesn't help with code clarity. If all you want to do is map a name to a value you can use a Dictionary, which is really what ExpandoObject uses internally, as demonstrated by the cast in the code above.

score 1 · Answer 2 · answered Oct 01 '11 at 15:37

1

C# is not designed for that sort of thing at the language level. You will have to use reflection to achieve that, and only for fields, not local variables (which cannot be accessed via reflection).

answered Oct 01 '11 at 15:37

C. K. Young

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score -1 · Answer 3 · answered Oct 01 '11 at 15:41

Such dynamic access to class members can be achieved via reflection.

class Foo
{
    string test;
    string hello;

    void Bar()
    {
        test = "hello";

        typeof(Foo).InvokeMember( test, 
           BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.SetField, 
           null, this, new object[] { "newvalue" } );
    }
}

How to dynamically set variable value with C#?

3 Answers3