Define a reference with name "system.imports".

    <namespaceimports id="system.imports">
    <import namespace="System" />
    <import namespace="System.Data" />
</namespaceimports>

Use the predefined set of imports to compile a VB.NET assembly.

    <vbc target="exe" output="HelloWorld.exe" rootnamespace="HelloWorld">
    <imports refid="system.imports" />
    <sources>
        <include name="**/*.vb" />
    </sources>
    <references>
        <include name="System.dll" />
        <include name="System.Data.dll" />
    </references>
</vbc>