Gtk#-3 with GtkBuilder

builder.csproj

<?xml version="1.0" encoding="utf-8"?>
<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup>
    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
    <Platform Condition=" '$(Platform)' == '' ">x86</Platform>
    <ProductVersion>10.0.0</ProductVersion>
    <SchemaVersion>2.0</SchemaVersion>
    <ProjectGuid>{DBD0AF03-1593-413F-89D3-C3012694EA3A}</ProjectGuid>
    <OutputType>WinExe</OutputType>
    <RootNamespace>builder</RootNamespace>
    <AssemblyName>builder</AssemblyName>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|x86' ">
    <DebugSymbols>True</DebugSymbols>
    <DebugType>full</DebugType>
    <Optimize>False</Optimize>
    <OutputPath>bin\Debug</OutputPath>
    <DefineConstants>DEBUG;</DefineConstants>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
    <PlatformTarget>x86</PlatformTarget>
    <ConsolePause>False</ConsolePause>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|x86' ">
    <DebugType>none</DebugType>
    <Optimize>True</Optimize>
    <OutputPath>bin\Release</OutputPath>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
    <PlatformTarget>x86</PlatformTarget>
    <ConsolePause>False</ConsolePause>
  </PropertyGroup>
  <ItemGroup>
    <Reference Include="System" />
    <Reference Include="Mono.Posix" />
    <Reference Include="gtk-sharp, Version=3.0.0.0, Culture=neutral, PublicKeyToken=35e10195dab3c99f">
      <Private>False</Private>
      <Package>gtk-sharp-3.0</Package>
    </Reference>
    <Reference Include="atk-sharp, Version=3.0.0.0, Culture=neutral, PublicKeyToken=35e10195dab3c99f">
      <Package>gtk-sharp-3.0</Package>
    </Reference>
    <Reference Include="gdk-sharp, Version=3.0.0.0, Culture=neutral, PublicKeyToken=35e10195dab3c99f">
      <Package>gtk-sharp-3.0</Package>
    </Reference>
    <Reference Include="gdk-sharp, Version=3.0.0.0, Culture=neutral, PublicKeyToken=35e10195dab3c99f">
      <Package>gtk-sharp-3.0</Package>
      <Private>False</Private>
    </Reference>
    <Reference Include="pango-sharp, Version=3.0.0.0, Culture=neutral, PublicKeyToken=35e10195dab3c99f">
      <Private>False</Private>
      <Package>gtk-sharp-3.0</Package>
    </Reference>
    <Reference Include="glib-sharp, Version=3.0.0.0, Culture=neutral, PublicKeyToken=35e10195dab3c99f">
      <Private>False</Private>
      <Package>glib-sharp-3.0</Package>
    </Reference>
  </ItemGroup>
  <ItemGroup>
    <Compile Include="Main.cs" />
    <Compile Include="AssemblyInfo.cs" />
    <Compile Include="gtk-gui\generated.cs" />
  </ItemGroup>
  <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
  <ItemGroup>
    <EmbeddedResource Include="gtk-gui\gui.stetic">
      <LogicalName>gui.stetic</LogicalName>
    </EmbeddedResource>
  </ItemGroup>
</Project>

builder.sln


Microsoft Visual Studio Solution File, Format Version 11.00
# Visual Studio 2010
Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "builder", "builder.csproj", "{DBD0AF03-1593-413F-89D3-C3012694EA3A}"
EndProject
Global
	GlobalSection(SolutionConfigurationPlatforms) = preSolution
		Debug|x86 = Debug|x86
		Release|x86 = Release|x86
	EndGlobalSection
	GlobalSection(ProjectConfigurationPlatforms) = postSolution
		{DBD0AF03-1593-413F-89D3-C3012694EA3A}.Debug|x86.ActiveCfg = Debug|x86
		{DBD0AF03-1593-413F-89D3-C3012694EA3A}.Debug|x86.Build.0 = Debug|x86
		{DBD0AF03-1593-413F-89D3-C3012694EA3A}.Release|x86.ActiveCfg = Release|x86
		{DBD0AF03-1593-413F-89D3-C3012694EA3A}.Release|x86.Build.0 = Release|x86
	EndGlobalSection
	GlobalSection(MonoDevelopProperties) = preSolution
		StartupItem = builder.csproj
	EndGlobalSection
EndGlobal

builder.ui

<?xml version="1.0" encoding="UTF-8"?>
<interface>
  <!-- interface-requires gtk+ 3.0 -->
  <object class="GtkWindow" id="window1">
    <property name="can_focus">False</property>
    <property name="title" translatable="yes">My GtkBuilder window</property>
    <property name="icon_name">emblem-important</property>
    <child>
      <object class="GtkBox" id="box1">
        <property name="visible">True</property>
        <property name="can_focus">False</property>
        <property name="orientation">vertical</property>
        <child>
          <object class="GtkLabel" id="label1">
            <property name="visible">True</property>
            <property name="can_focus">False</property>
            <property name="label" translatable="yes">label</property>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">0</property>
          </packing>
        </child>
        <child>
          <object class="GtkCheckButton" id="checkbutton1">
            <property name="label" translatable="yes">checkbutton</property>
            <property name="use_action_appearance">False</property>
            <property name="visible">True</property>
            <property name="can_focus">True</property>
            <property name="receives_default">False</property>
            <property name="use_action_appearance">False</property>
            <property name="xalign">0</property>
            <property name="draw_indicator">True</property>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">1</property>
          </packing>
        </child>
        <child>
          <object class="GtkStatusbar" id="statusbar1">
            <property name="visible">True</property>
            <property name="can_focus">False</property>
            <property name="orientation">vertical</property>
            <property name="spacing">2</property>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">2</property>
          </packing>
        </child>
      </object>
    </child>
  </object>
</interface>

builder.userprefs

<Properties>
  <MonoDevelop.Ide.Workspace ActiveConfiguration="Debug|x86" />
  <MonoDevelop.Ide.Workbench ActiveDocument="Main.cs">
    <Files>
      <File FileName="Main.cs" Line="1" Column="1" />
    </Files>
    <Pads>
      <Pad Id="ProjectPad">
        <State expanded="True">
          <Node name="builder" expanded="True">
            <Node name="References" expanded="True" selected="True" />
            <Node name="UserInterface" expanded="True" />
          </Node>
        </State>
      </Pad>
      <Pad Id="ClassPad">
        <State expanded="True" selected="True" />
      </Pad>
      <Pad Id="MonoDevelop.Debugger.WatchPad">
        <State />
      </Pad>
    </Pads>
  </MonoDevelop.Ide.Workbench>
  <MonoDevelop.Ide.DebuggingService.Breakpoints>
    <BreakpointStore />
  </MonoDevelop.Ide.DebuggingService.Breakpoints>
  <MonoDevelop.Ide.DebuggingService.PinnedWatches />
</Properties>

Main.cs

using System;
using Gtk;

namespace builder
{
	class MainWin
	{
		[Gtk.Builder.Object("window1")] Window window1;
		public void OnToggled(object sender, EventArgs args)
		{
			Console.WriteLine("toggled");
		}

		public MainWin(Builder builder)
		{
			window1 = (Window)builder.GetObject("window1");
			builder.Autoconnect(this);
			window1.ShowAll();
		}
	}

	class MainClass
	{

		public static void Main(string[] args)
		{
			Gtk.Application.Init();
			var builder = new Gtk.Builder();
			builder.AddFromFile("/home/carlos/progs/builder/builder.ui");
			var win = new MainWin(builder);

			Application.Run();
		}
	}
}