The Import element is used to insert one project file into another project file. The project file that is being imported must be a valid MSBuild project file and contain well-formed XML. The Project attribute specifies the path to the imported project file. For more information on the Import element, see Import Element (MSBuild).

To import a project

When MSBuild reaches an Import element, the imported project is effectively inserted into the importing project at the location of the Import element. Therefore, the location of the Import element can affect the values of properties and items. It is important to understand the properties and items that are set by the imported project, and the properties and items that the imported project uses.

When the project builds, all properties are evaluated first, followed by items. For example, the following XML defines the imported project file MyCommon.targets:

<Project xmlns=”http://schemas.microsoft.com/developer/msbuild/2003”>
    <PropertyGroup>
        <Name>MyCommon</Name>
    </PropertyGroup>

    <Target Name="Go">
        <Message Text="Name="$(Name)""/>
    </Target>
</Project>

The following XML defines MyApp.proj, which imports MyCommon.targets:

<Project
    DefaultTargets="Go"
    xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <PropertyGroup>
        <Name>MyApp</Name>
    </PropertyGroup>
    <Import Project="MyCommon.targets"/>
</Project>

When the project builds, the following message is displayed:

Name="MyCommon"

Because the project is imported after the property Name has been defined in MyApp.proj, the definition of Name in MyCommon.targets overrides the definition in MyApp.proj. If, the project is imported before the property Name is defined, the build would display the following message:

Name="MyApp"

Use the following approach when importing projects

The following code example shows the MyCommon.targets file that the second code example imports. The .targets file evaluates properties from the importing project to configure the build.

<Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <PropertyGroup>
        <Flavor Condition="'$(Flavor)'==''">DEBUG</Flavor>
        <Optimize Condition="'$(Flavor)'=='RETAIL'">yes</Optimize>
        <appname>$(MSBuildProjectName)</appname>
    <PropertyGroup>
    <Target Name="Build">
        <Csc Sources="hello.cs"
            Optimize="$(Optimize)"
            OutputAssembly="$(appname).exe"/>
    </Target>
</Project>

The following code example imports the MyCommon.targets file.

<Project DefaultTargets="Build"
    xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <PropertyGroup>
        <Flavor>RETAIL</Flavor>
    </PropertyGroup>
    <Import Project="MyCommon.targets"/>
</Project>

Concepts

Reference