I have used Apache's Ant for quite a while. Now in there is NANT in the C# and .NET world. However Visual Studio only uses MSBUILD. Here's how you make it so that Visual Studio will use NANT instead:
First, open up the .csproj file and modify the DefaultTargets to "Nant" as follows:
<Project ToolsVersion="4.0" DefaultTargets="Nant" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
Next, add the following at the bottom of the file:
<Target Name="Nant">
<Exec Command="CALL nant.exe -D:buildtype=$(Configuration)" />
</Target>
Now, in your NANT's Default.build file, add this as the build target:
<target name="build" description="Compiles the source code">
<echo message="Build Type: ${buildtype}"/>
<property name="debug" value="false"/>
<if test="${buildtype == 'Debug'}">
<property name="debug" value="true"/>
</if>
<echo message="Debug = ${debug}"/>
<!-- Make sure the build directory is present -->
<mkdir dir="${build.dir}" unless="${directory::exists('build')}" />
<!-- Compile sources -->
<csc target="library" output="${build.dir}\${project::get-name()}.dll" debug="${debug}">
<sources>
<include name="**/*.cs" />
</sources>
<references>
<include name="${log4net.dir}\log4net.dll"/>
</references>
</csc>
<!-- Copy log4net over. -->
<copy file="${log4net.dir}\log4net.dll" tofile="${build.dir}\log4net.dll"/>
</target>
This will use whatever build configuration used in Visual Studio. It will also set debug mode if you build it in Debug (to generate those .pdb files).