It sounds like what you want is the "compiler as a service". That is not in MS .NET 4.0, but may be in a later release. It is already in Mono, though. Until then, the options available are:

• use CSharpCodeProvider, but you'll have to load it in as a method (and create a delegate to it) via reflection
• use CodeDom
• use Reflection.Emit
• use Expression

In 4.0, the Expression API is far richer than it was in 3.5, allowing most common constructs without the pain of CodeDom. But don't discount Reflection.Emit - it takes a little while to get your head around ILGenerator and using the stack, but it isn't as bad as people tend to think.

As a side-note, don't use Invoke from DynamicMethod unless you only want to execute it once. The better approach is to use CreateDelegate, then store (and re-use) that delegate:

var dm = new System.Reflection.Emit.DynamicMethod("My_method", typeof(string), null); var il = dm.GetILGenerator(); il.Emit(OpCodes.Ldstr, "Hello, world!"); il.Emit(OpCodes.Ret); Func<string> func = (Func<string>)dm.CreateDelegate(typeof(Func<string>)); func(); 

It sounds like what you want is the "compiler as a service". That is not in MS .NET 4.0, but may be in a later release. It is already in Mono, though. Until then, the options available are:

• use CSharpCodeProvider, but you'll have to load it in as a method (and create a delegate to it) via reflection
• use CodeDom
• use Reflection.Emit
• use Expression

In 4.0, the Expression API is far richer than it was in 3.5, allowing most common constructs without the pain of CodeDom. But don't discount Reflection.Emit - it takes a little while to get your head around ILGenerator and using the stack, but it isn't as bad as people tend to think.

As a side-note, don't use Invoke from DynamicMethod unless you only want to execute it once. The better approach is to use CreateDelegate, then store (and re-use) that delegate:

var dm = new System.Reflection.Emit.DynamicMethod("My_method", typeof(string), null); var il = dm.GetILGenerator(); il.Emit(OpCodes.Ldstr, "Hello, world!"); il.Emit(OpCodes.Ret); Func<string> func = (Func<string>)dm.CreateDelegate(typeof(Func<string>)); var s = func(); 

Or with the Expression API:

var lambda =Expression.Lambda<Func<string>>(Expression.Constant("Hello, world")); var func = lambda.Compile(); var s = func();