How to Create C# Inline Task in MSBuild

This article shows how to create and call C# msbuild inline task with the UsingTask element. As an example, the UninstallString of the ‘Node.js’ package is searched.

Create UsingTask Element

Inline Task can use the element ‘UsingTask‘, where C# code with optional Input and Output parameters is specified.

  <UsingTask
    TaskName="FindUninstallString"
    TaskFactory="CodeTaskFactory"
    AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.Core.dll" >

    <ParameterGroup>
    </ParameterGroup>

    <Task>
      <Reference Include="" />
      <Using Namespace="" />
      <Code Type="Fragment" Language="cs">

      </Code>
    </Task>
  </UsingTask>

Define Input and Output Parameters

Under UsingTask Element, there is a child element <ParameterGroup> defining Input and Output Parameters.

      <ParameterGroup>
             <InstalledPackage ParameterType="System.String" Required="true" />
             <ReturnString ParameterType="System.String" Output="true" />
      </ParameterGroup>

Define C# Code

In this example, the UninstallString for specified Input Parameter ‘InstalledPackage’ will be searched and returned.

      <Code Type="Fragment" Language="cs">
          <![CDATA[
 
		   RegistryKey localMachine = RegistryKey.OpenBaseKey(Microsoft.Win32.RegistryHive.LocalMachine, RegistryView.Registry64);
		   
		   string regArea = @"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall";
		   RegistryKey packagesRoot = localMachine.OpenSubKey(regArea);
		   string[] packageslisted = packagesRoot.GetSubKeyNames();
		   string uninstallCommand = String.Empty;
			
			foreach (string p in packageslisted)
			{
				RegistryKey installProperties = packagesRoot.OpenSubKey(p);
				if (installProperties != null)
				{
					string displayName = (string)installProperties.GetValue("DisplayName");

					if ((displayName != null) && displayName.Contains(InstalledPackage))
					{
						uninstallCommand = (string)installProperties.GetValue("UninstallString");
					}
				}
			}
            ReturnString = uninstallCommand ;
          ]]>
      </Code>

Add NameSpace and Reference

Add References and NameSpaces if needed to run the task.

<Using Namespace="Microsoft.Win32"/>

Call the msbuild inline task from Target

The target contains a set of tasks for MSBuild to run, and here this ‘GetUninstallString’ target calls the C# inline Task ‘FindUninstallString’.

 <Target Name="GetUninstallString">

	<FindUninstallString InstalledPackage="Node.js" > 
		<Output TaskParameter="ReturnString" ItemName="UninstallStringForPackage"/>
	</FindUninstallString>

       <Message Text="Unstaill String for Search Product is " />
  </Target>

Build the Target

msbuild test.msbuild /t:GetUninstallString

Run:

You may be interested in reading more articles:

How to Run C# Code in PowerShell

How to Update Files With Version in MSBuild