Question

Is CompileAssemblyFromDom faster than CompileAssemblyFromSource?

It should be as it presumably bypasses the compiler front-end.

Answer 1

CompileAssemblyFromDom compiles to a .cs file which is then run through the normal C# compiler.

Example:

using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.CSharp; using System.CodeDom; using System.IO; using System.CodeDom.Compiler; using System.Reflection;  namespace CodeDomQuestion {     class Program     {          private static void Main(string[] args)         {             Program p = new Program();             p.dotest("C:\\fs.exe");         }          public void dotest(string outputname)         {             CSharpCodeProvider cscProvider = new CSharpCodeProvider();             CompilerParameters cp = new CompilerParameters();             cp.MainClass = null;             cp.GenerateExecutable = true;             cp.OutputAssembly = outputname;                          CodeNamespace ns = new CodeNamespace("StackOverflowd");              CodeTypeDeclaration type = new CodeTypeDeclaration();             type.IsClass = true;             type.Name = "MainClass";             type.TypeAttributes = TypeAttributes.Public;                          ns.Types.Add(type);              CodeMemberMethod cmm = new CodeMemberMethod();             cmm.Attributes = MemberAttributes.Static;             cmm.Name = "Main";             cmm.Statements.Add(new CodeSnippetExpression("System.Console.WriteLine('f'zxcvv)"));             type.Members.Add(cmm);              CodeCompileUnit ccu = new CodeCompileUnit();             ccu.Namespaces.Add(ns);              CompilerResults results = cscProvider.CompileAssemblyFromDom(cp, ccu);              foreach (CompilerError err in results.Errors)                 Console.WriteLine(err.ErrorText + " - " + err.FileName + ":" + err.Line);              Console.WriteLine();         }     } } 

which shows errors in a (now nonexistent) temp file:

) expected – c:\Documents and Settings\jacob\Local Settings\Temp\x59n9yb-.0.cs:17

; expected – c:\Documents and Settings\jacob\Local Settings\Temp\x59n9yb-.0.cs:17

Invalid expression term ‘)’ – c:\Documents and Settings\jacob\Local Settings\Tem p\x59n9yb-.0.cs:17

So I guess the answer is "no"