How to: Specify Build Events (C#)

Article
11/15/2016

Note

This article applies to Visual Studio 2015. If you're looking for the latest Visual Studio documentation, see Visual Studio documentation. We recommend upgrading to the latest version of Visual Studio. Download it here

Use build events to specify commands that run before the build starts or after the build finishes. Build events are executed only if the build successfully reaches those points in the build process.

When a project is built, pre-build events are added to a file that is named PreBuildEvent.bat and post-build events are added to a file that is named PostBuildEvent.bat. If you want to ensure error checking, add your own error-checking commands to the build steps.

Note

Your computer might show different names or locations for some of the Visual Studio user interface elements in the following instructions. The Visual Studio edition that you have and the settings that you use determine these elements. For more information, see Personalizing the IDE.

How to Specify Pre-Build and Post-Build Events

To specify a build event

In Solution Explorer, select the project for which you want to specify the build event.
On the Project menu, click Properties.
Select the Build Events tab.
In the Pre-build event command line box, specify the syntax of the build event.

Note

Pre-build events do not run if the project is up to date and no build is triggered.
In the Post-build event command line box, specify the syntax of the build event.

Note

Add a call statement before all post-build commands that run .bat files. For example, call C:\MyFile.bat or call C:\MyFile.bat call C:\MyFile2.bat.
In the Run the post-build event box, specify under what conditions to run the post-build event.

Note

To add lengthy syntax, or to select any build macros from the Pre-build Event/Post-build Event Command Line Dialog Box, click the Ellipsis button (…) to display an edit box.

The build event syntax can include any command that is valid at a command prompt or in a .bat file. The name of a batch file should be preceded by call to ensure that all subsequent commands are executed.

Note If your pre-build or post-build event does not complete successfully, you can terminate the build by having your event action exit with a code other than zero (0), which indicates a successful action.

Example: How to Change Manifest Information by Using a Post-Build Event

The following procedure shows how to set the minimum operating system version in the application manifest by using an .exe command that is called from a post-build event (the .exe.manifest file in the project directory). The minimum operating system version is a four-part number such as 4.10.0.0. To do this, the command will change the <dependentOS> section of the manifest:

<dependentOS>
   <osVersionInfo>
      <os majorVersion="4" minorVersion="10" buildNumber="0" servicePackMajor="0" />
   </osVersionInfo>
</dependentOS>

To create an .exe command to change the application manifest

Create a console application for the command. From the File menu, point to New, and then click Project.
In the New Project dialog box, expand Visual C#, click Windows, and then click the Console Application template. Name the project ChangeOSVersionCS.
In Program.cs, add the following line to the other using statements at the top of the file:
```
using System.Xml;
```

In the ChangeOSVersionCS namespace, replace the Program class implementation with the following code:

class Program
{
   /// <summary>
   /// This function will set the minimum operating system version for a ClickOnce application.
   /// </summary>
   /// <param name="args">
   /// Command Line Arguments:
   /// 0 - Path to application manifest (.exe.manifest).
   /// 1 - Version of OS
   ///</param>
   static void Main(string[] args)
   {
      string applicationManifestPath = args[0];
      Console.WriteLine("Application Manifest Path: " + applicationManifestPath);

      // Get version name.
      Version osVersion = null;
      if (args.Length >=2 ){
         osVersion = new Version(args[1]);
      }else{
         throw new ArgumentException("OS Version not specified.");
      }
      Console.WriteLine("Desired OS Version: " + osVersion.ToString());

      XmlDocument document;
      XmlNamespaceManager namespaceManager;
      namespaceManager = new XmlNamespaceManager(new NameTable());
      namespaceManager.AddNamespace("asmv1", "urn:schemas-microsoft-com:asm.v1");
      namespaceManager.AddNamespace("asmv2", "urn:schemas-microsoft-com:asm.v2");

      document = new XmlDocument();
      document.Load(applicationManifestPath);

      string baseXPath;
      baseXPath = "/asmv1:assembly/asmv2:dependency/asmv2:dependentOS/asmv2:osVersionInfo/asmv2:os";

      // Change minimum required operating system version.
      XmlNode node;
      node = document.SelectSingleNode(baseXPath, namespaceManager);
      node.Attributes["majorVersion"].Value = osVersion.Major.ToString();
      node.Attributes["minorVersion"].Value = osVersion.Minor.ToString();
      node.Attributes["buildNumber"].Value = osVersion.Build.ToString();
      node.Attributes["servicePackMajor"].Value = osVersion.Revision.ToString();

      document.Save(applicationManifestPath);
   }
}

The command takes two arguments: the path of the application manifest (that is, the folder in which the build process creates the manifest, typically Projectname.publish), and the new operating system version.

Build the project. On the Build menu, click Build Solution.
Copy the .exe file to a directory such as C:\TEMP\ChangeOSVersionVB.exe.

Next, invoke this command in a post-build event to modify the application manifest.

To invoke a post-build event to modify the application manifest

Create a Windows application for the project to be published. From the File menu, point to New, and then click Project.
In the New Project dialog box, expand Visual C#, click Windows, and then click the Windows Forms Application template. Name the project CSWinApp.
With the project selected in Solution Explorer, on the Project menu, click Properties.
In the Project Designer, locate the Publish page and set Publishing location to C:\TEMP\.
Publish the project by clicking Publish Now.

The manifest file will be built and put in C:\TEMP\CSWinApp_1_0_0_0\CSWinApp.exe.manifest. To view the manifest, right-click the file, click Open with, select Select the program from a list, and then click Notepad.

Search in the file for the <osVersionInfo> element. For example, the version might be:
```
<os majorVersion="4" minorVersion="10" buildNumber="0" servicePackMajor="0" />
```
In the Project Designer, click the Build Events tab and click the Edit Post-build button.
In the Post-build Event Command Line box, type the following command:

C:\TEMP\ChangeOSVersionCS.exe "$(TargetPath).manifest" 5.1.2600.0

When you build the project, this command will change the minimum operating system version in the application manifest to 5.1.2600.0.

Because the $(TargetPath) macro expresses the full path for the executable being created, the $(TargetPath).manifest will specify the application manifest created in the bin directory. Publishing will copy this manifest to the publishing location that you set earlier.
Publish the project again. Go to the Publish page and click Publish Now.

View the manifest again. To view the manifest, open the publish directory, right-click the file, click Open with, select Select the program from a list, and then click Notepad.

The version should now read:
```
<os majorVersion="5" minorVersion="1" buildNumber="2600" servicePackMajor="0" />
```