UsingTask element (MSBuild)

Maps the task that is referenced in a Task element to the assembly that contains the task implementation.

<Project> <UsingTask>

Syntax

<UsingTask TaskName="TaskName"
    AssemblyName = "AssemblyName"
    TaskFactory = "ClassName"
    Condition="'String A'=='String B'" />

Note

Unlike properties and items, the first UsingTask element that applies to a TaskName will be used; to override tasks you must define a new UsingTask before the existing one.

Attributes and elements

The following sections describe attributes, child elements, and parent elements.

Attributes

Attribute Description
Architecture Optional attribute.

Specifies that the task must run in a process of the specified bitness. If the current process does not satisfy the requirement, the task will be run in a task host process that does.

Supported values are x86 (32-bit), x64 (64-bit), CurrentArchitecture, and * (any architecture).
AssemblyName Either the AssemblyName attribute or the AssemblyFile attribute is required.

The name of the assembly to load. The AssemblyName attribute accepts strong-named assemblies, although strong-naming is not required. Using this attribute is equivalent to loading an assembly by using the Load method in .NET.

You cannot use this attribute if the AssemblyFile attribute is used.
AssemblyFile Either the AssemblyName or the AssemblyFile attribute is required.

The file path of the assembly. This attribute accepts full paths or relative paths. Relative paths are relative to the directory of the project file or targets file where the UsingTask element is declared. Using this attribute is equivalent to loading an assembly by using the LoadFrom method in .NET.

You cannot use this attribute if the AssemblyName attribute is used.
Runtime Optional attribute.

Specifies that the task must run in a .NET Framework runtime of the specified version. If the current process does not satisfy the requirement, the task will be run in a task host process that does. Not supported in .NET Core MSBuild.

Supported values are CLR2 (.NET Framework 3.5), CLR4 (.NET Framework 4.7.2 or higher), CurrentRuntime, and * (any runtime).
TaskFactory Optional attribute.

Specifies the class in the assembly that is responsible for generating instances of the specified Task name. The user may also specify a Task as a child element that the task factory receives and uses to generate the task. The contents of the Task are specific to the task factory.
TaskName Required attribute.

The name of the task to reference from an assembly. If ambiguities are possible, this attribute should always specify full namespaces. If there are ambiguities, MSBuild chooses an arbitrary match, which could produce unexpected results.
Condition Optional attribute.

The condition to evaluate. For more information, see Conditions.

Child elements

Element Description
ParameterGroup The set of parameters that appear on the task that is generated by the specified TaskFactory.
Task The data that is passed to the TaskFactory to generate an instance of the task.

Parent elements

Element Description
Project Required root element of an MSBuild project file.

Remarks

Environment variables, command-line properties, project-level properties, and project-level items can be referenced in the UsingTask elements included in the project file either directly or through an imported project file. For more information, see Tasks.

Note

Project-level properties and items have no meaning if the UsingTask element is coming from one of the .tasks files that are globally registered with the MSBuild engine. Project-level values are not global to MSBuild.

In MSBuild 4.0, using tasks can be loaded from .overridetask files.

The assembly containing the custom task is loaded when the Task is first used.

Example 1

The following example shows how to use the UsingTask element with an AssemblyName attribute.

<UsingTask TaskName="MyTask" AssemblyName="My.Assembly" TaskFactory="MyTaskFactory">
       <ParameterGroup>
              <Parameter1 ParameterType="System.String" Required="False" Output="False"/>
              <Parameter2 ParameterType="System.Int" Required="True" Output="False"/>
              ...
</ParameterGroup>
       <Task>
      ... Task factory-specific data ...
       </Task>
</UsingTask>

Example 2

The following example shows how to use the UsingTask element with an AssemblyFile attribute.

<UsingTask TaskName="Email"
              AssemblyFile="c:\myTasks\myTask.dll" />

See also