Build csproj for MONO that requires dlls - dll

Question

I have a line of code that I got from a site called Zetcode, and in this to build the first example, I compile the code like this:
gmcs -r:System.Windows.Forms.dll -r:System.Drawing.dll 01-simple-cs-example.cs -out:simple-sample.exe
This builds the exe that draws my window, but I don't think my csproj file is correct.
<Project DefaultTargest="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<PropertyGroup>
<!-- This Property will make a variable named MSBuildSample, then you can use it to
assign to whatever in the script.
Properties are variables inside the script.
-->
<SrcPath>src\</SrcPath>
<AssemblyName>01-simple-cs-example</AssemblyName>
<OutputPath>bin\</OutputPath>
</PropertyGroup>
<ItemGroup>
<!-- This Compile statement, gathers all the source files listed in an item called Compiled
ItemGroups interact with the source code.
-->
<Compile Include="$(SrcPath)01-simple-cs-example.cs" />
</ItemGroup>
<!-- In the Build target, the Inputs and Outputs targets which looks to see if the files have been updated,
or if the files are existent. If the files have not been changed, then the Build target is skipped.
-->
<Target Name="Build" Inputs="#(Compile)" Outputs="$(OutputPath)$(AssemblyName).exe" >
<!-- The MakeDir directive will create the directory in the property group above, if it meets the
condition stated in the Condition= statement.
-->
<Message Text="Creating the output path $(OutputPath)." />
<MakeDir Directories="$(OutputPath)" Condition="!Exists('$(OutputPath)')" />
<!-- This Csc is the .NET C# compiler, which then uses the ItemGroup of collected sources called, Compile
-->
<Message Text="Compiling the source code." />
<Csc Sources="#(Compile)" OutputAssembly="$(OutputPath)$(AssemblyName).exe" />
</Target>
</Project>
This is the result from trying to run xbuild, and msbuild.
C:\Users\User01\Dropbox\programming\csharp\zetcode-csharp-winforms\01-simple-cs-example>xbuild
XBuild Engine Version 3.3.0.0
Mono, Version 3.3.0.0
Copyright (C) Marek Sieradzki 2005-2008, Novell 2008-2011.
Build started 7/25/2014 2:47:41 PM.
__________________________________________________
Project "C:\Users\User01\Dropbox\programming\csharp\zetcode-csharp-winforms\01-simple-cs-example\01-simple-cs-example.csproj" (default target(s)):
Target Build:
Created directory "bin\"
Tool C:\mono\Mono-3.2.3\bin\gmcs.bat execution started with arguments: /out:bin\01-simple-cs-example.exe src\01-simple-cs-example.cs
src\01-simple-cs-example.cs(1,22): error CS0234: The type or namespace name `Forms' does not exist in the namespace `System.Windows'. Are you missing `System.Windows.Forms' assembly reference?
src\01-simple-cs-example.cs(2,14): error CS0234: The type or namespace name `Drawing' does not exist in the namespace `System'. Are you missing `System.Drawing' assembly reference?
src\01-simple-cs-example.cs(4,23): error CS0246: The type or namespace name `Form' could not be found. Are you missing an assembly reference?
Task "Csc" execution -- FAILED
Done building target "Build" in project "C:\Users\User01\Dropbox\programming\csharp\zetcode-csharp-winforms\01-simple-cs-example\01-simple-cs-example.csproj".-- FAILED
Done building project "C:\Users\User01\Dropbox\programming\csharp\zetcode-csharp-winforms\01-simple-cs-example\01-simple-cs-example.csproj".-- FAILED
Build FAILED.
Errors:
C:\Users\User01\Dropbox\programming\csharp\zetcode-csharp-winforms\01-simple-cs-example\01-simple-cs-example.csproj (default targets) ->
(Build target) ->
src\01-simple-cs-example.cs(1,22): error CS0234: The type or namespace name `Forms' does not exist in the namespace `System.Windows'. Are you missing `System.Windows.Forms' assembly reference?
src\01-simple-cs-example.cs(2,14): error CS0234: The type or namespace name `Drawing' does not exist in the namespace `System'. Are you missing `System.Drawing' assembly reference?
src\01-simple-cs-example.cs(4,23): error CS0246: The type or namespace name `Form' could not be found. Are you missing an assembly reference?
0 Warning(s)
3 Error(s)
Time Elapsed 00:00:01.5341534
This is the result from the MSBuild run. MSBuild completed successfully, but I imagine that's because MSBuild knows where to look without me having to specify it in the csproj file.
C:\Users\User01\Dropbox\programming\csharp\zetcode-csharp-winforms\01-simple-cs-example>MSBuild
Microsoft (R) Build Engine version 4.0.30319.18408
[Microsoft .NET Framework, version 4.0.30319.18444]
Copyright (C) Microsoft Corporation. All rights reserved.
Build started 7/25/2014 2:48:04 PM.
Project "C:\Users\User01\Dropbox\programming\csharp\zetcode-csharp-winforms\01-simple-cs-example\01-simple-cs-example.csproj" on node 1 (default targets).
Build:
C:\Windows\Microsoft.NET\Framework\v2.0.50727\Csc.exe /out:bin\01-simple-cs-example.exe src\01-simple-cs-example.cs
Done Building Project "C:\Users\User01\Dropbox\programming\csharp\zetcode-csharp-winforms\01-simple-cs-example\01-simple-cs-example.csproj" (default targets).
Build succeeded.
0 Warning(s)
0 Error(s)
Time Elapsed 00:00:04.36
I don't know what to put into the csproj file to make it load those DLL's that I used in the command line to compile using gmcs. Any clues?
-- EDIT 2014-08-20 --
After using the answer from knocte, I was able to see how the References are added in a csproj file. Its as simple as adding an item group, and adding the References you listed with using in the C# source file.
<ItemGroup>
<Reference Include="System.Windows.Forms" />
<Reference Include="System.Drawing" />
<Reference Include="System" />
</ItemGroup>
This is the manual way to do it if you're building the csproj file manually.

Answer 1

Just use an IDE (MonoDevelop or Visual Studio) to add a GAC-reference to System.Windows.Forms and System.Drawing libraries.