Dynamically change the Value of enum in C#?

You can't do this, it is a strongly-typed value, if you like.

The elements of the enum are read-only and changing them at runtime is not possible, nor would it be desirable.

What might suit you is extension of the enum to expose a new value to use with new features and whatnot, such as:

public enum TestType:int { Aphasia = 2, FocusedAphasia = 5 SomeOtherAphasia = 10 } 

Not being quite clued up on exactly what you want to do, I can't well suggest much else.

Well, this question is 7 years far while I am writing my answer. I still want to write it, maybe it will be useful for someone later.

Changing enum values in runtime is not possible, but there is a way to play around by casting int variable into enum, and defining those ints with their values in a dictionary as in below:

// Define enum TestType without values enum TestType{} // Define a dictionary for enum values Dictionary<int,string> d = new Dictionary<int,string>(); void Main() { int i = 5; TestType s = (TestType)i; TestType e = (TestType)2; // Definging enum int values with string values d.Add(2,"Aphasia"); d.Add(5,"FocusedAphasia"); // Results: Console.WriteLine(d[(int)s]); // Result: FocusedAphasia Console.WriteLine(d[(int)e]); // Result: Aphasia } 

In this way, you have a dynamic dictionary for enum values without any written inside it. In case you want any other value for the enum, then you can make a method to add it:

public void NewEnumValue(int i, string v) { try { string test = d[i]; Console.WriteLine("This Key is already assigned with value: " + test); } catch { d.Add(i,v); } } 

So, your last code in use should be this way:

// Define enum TestType without values enum TestType{} // Define a dictionary for enum values Dictionary<int,string> d = new Dictionary<int,string>(); public void NewEnumValue(int i, string v) { try { string test = d[i]; Console.WriteLine("This Key is already assigned with value: " + test); } catch { d.Add(i,v); Console.WriteLine("Addition Done!"); } } void Main() { int i = 5; TestType s = (TestType)i; TestType e = (TestType)2; // Definging enum int values with string values NewEnumValue(2,"Aphasia"); NewEnumValue(5,"FocusedAphasia"); Console.WriteLine("You will add int with their values; type 0 to " + "exit"); while(true) { Console.WriteLine("enum int:"); int ii = Convert.ToInt32(Console.ReadLine()); if (ii == 0) break; Console.WriteLine("enum value:"); string v = Console.ReadLine(); Console.WriteLine("will try to assign the enum TestType with " + "value: " + v + " by '" + ii + "' int value."); NewEnumValue(ii,v); } // Results: Console.WriteLine(d[(int)s]); // Result: FocusedAphasia Console.WriteLine(d[(int)e]); // Result: Aphasia } 

Well actually you can. Say you have an assembly (dll) with the original TestType. You can unload that assembly (this is somewhat complicated), rewrite the assembly with a new TestType and reload it.

You can not, however, change the type of existing variables because those have to be disposed of before the assembly can be unloaded.