C#

^[\w\.\-]+@[a-zA-Z0-9\-]+(\.[a-zA-Z0-9\-]{1,})*(\.[a-zA-Z]{2,3}){1,2}$

override void OnValidate(EventArgs e)
{
  base.OnValidate(e);
}

.assembly extern mscorlib
{
  .publickeytoken = (B7 7A 5C 56 19 34 E0 89 )
  .ver 1:1:4322:0
}
.assembly Test
{
  .ver 1:0:0:0
}
.module Test.exe
.class public auto ansi Test
{
  .method public hidebysig static void Main() cil managed
  {
    .entrypoint
    .maxstack 2
    .locals init (class Test t)
    newobj instance void Test2::.ctor()
    stloc.0
    ldloc.0
    callvirt instance string Test::Print()
    call void [mscorlib]System.Console::WriteLine(string)
    ret
  }

  .method public hidebysig specialname instance void .ctor() cil managed
  {
    ret
  }

  .method private hidebysig virtual instance string Print() cil managed
  {
    .maxstack 1
    ldstr "From Test (Private)"
    ret
  }
}
.class public auto ansi Test2 extends Test
{
  .method public hidebysig specialname instance void .ctor() cil managed
  {
    ret
  }

  .method private hidebysig virtual instance string Print() cil managed
  {
    .maxstack 1
    ldstr "From Test2 (Private)"
    ret
  }
}

class Test
{
  virtual void TestMethod(){}
  class Test2 : Test
  {
    override void TestMethod(){}
  }
}