C#

private void button1_Click(object sender, EventArgs e)
{
            AssemblyName asmName = new AssemblyName();
            asmName.Name = "HelloWorld";

            AssemblyBuilder asmBuilder = Thread.GetDomain().DefineDynamicAssembly(asmName, AssemblyBuilderAccess.RunAndSave);
            ModuleBuilder modBuilder = asmBuilder.DefineDynamicModule("HelloWorld");
            TypeBuilder typeBuilder = modBuilder.DefineType("Hello", TypeAttributes.Public, typeof(object), new Type[] { typeof(IHello) });

            MethodBuilder methodBuilder = typeBuilder.DefineMethod("SayHello", MethodAttributes.Private | MethodAttributes.Virtual, typeof(void), new Type[] { typeof(string) });

            typeBuilder.DefineMethodOverride(methodBuilder, typeof(IHello).GetMethod("SayHello"));
            ILGenerator il = methodBuilder.GetILGenerator();

            // string.Format("Hello, {0} World!", toWhom)
            il.Emit(OpCodes.Ldstr, "Hello, {0} World!");
            il.Emit(OpCodes.Ldarg_1);
            il.Emit(OpCodes.Call, typeof(string).GetMethod("Format", new Type[] { typeof(string), typeof(object) }));

            // Console.WriteLine("Hello, World!");
            il.Emit(OpCodes.Call, typeof(Console).GetMethod("WriteLine", new Type[] { typeof(string) }));
            il.Emit(OpCodes.Ret);

            Type type = typeBuilder.CreateType();
            IHello hello = (IHello)Activator.CreateInstance(type);

            hello.SayHello("Emit");
            asmBuilder.Save(asmName.Name + ".dll");
}

ComboBox combobox;

Public Form1(){InitializeComponent();}

if (DataGridView1.CurrentCell.ColumnIndex == 1)
{
 combobox = (ComboBox)e.Control;
 Function1();
}

try
{
  combobox.Items.Clear();
  string q = "select * from Table1";
  Con.Open();
  DataSet ds = new DataSet();
  NpgsqlDataAdapter da = new NpgsqlDataAdapter(q, Con);
  da.Fill(ds, "Table");
  for (int i = 0; i < (ds.Tables["Table"].Rows.Count); i++)
  {
   string name = ds.Tables["Table"].Rows[i]["name"].ToString();
   combobox.Items.Add(name);
  }
  Con.Close();
}
catch
{}

private void DataGridView1_DataError(object sender, DataGridViewDataErrorEventArgs e)
{}