Output Build Order of Visual Studio solution to a text file

This is a good candidate for a Visual Studio Plugin project.

1. Create a new Visual Studio Add-in project.
2. In the project creation wizard make sure you choose the following configuration in the Choose Add-in Options step (the other steps are not important, I'm assuming you'll use C#):

2. In the Connect.cs file, add the following fields:

   private BuildEvents _buildEvents;
   private Events _events;
   private bool buildEventConnected = false;
   

3. And add / modify these methods accordingly:

   public void OnConnection(object application, ext_ConnectMode connectMode, object addInInst, ref Array custom)
   {
       _applicationObject = (DTE2)application;
       _addInInstance = (AddIn)addInInst;
       _events = _applicationObject.Events;
       _buildEvents = _events.BuildEvents;
   
       if (connectMode != ext_ConnectMode.ext_cm_UISetup && !buildEventConnected)
       {
           _buildEvents.OnBuildDone +=
               new _dispBuildEvents_OnBuildDoneEventHandler(BuildEvents_OnBuildDone);
           buildEventConnected = true;
       }
   }
   
   private void BuildEvents_OnBuildDone(vsBuildScope Scope, vsBuildAction Action)
   {
       const string BUILD_OUTPUT_PANE_GUID = "{1BD8A850-02D1-11D1-BEE7-00A0C913D1F8}";
       TextDocument txtOutput = default(TextDocument);
       TextSelection txtSelection = default(TextSelection);
       Window vsWindow = default(Window);
       vsWindow = _applicationObject.Windows.Item(EnvDTE.Constants.vsWindowKindOutput);
       OutputWindow vsOutputWindow = default(OutputWindow);
       OutputWindowPane objBuildOutputWindowPane = default(OutputWindowPane);
       vsOutputWindow = (OutputWindow)vsWindow.Object;
       foreach (OutputWindowPane objOutputWindowPane in vsOutputWindow.OutputWindowPanes)
       {
           if (objOutputWindowPane.Guid.ToUpper() == BUILD_OUTPUT_PANE_GUID)
           {
               objBuildOutputWindowPane = objOutputWindowPane;
               break;
           }
       }
       txtOutput = objBuildOutputWindowPane.TextDocument;
       txtSelection = txtOutput.Selection;
       txtSelection.StartOfDocument(false);
       txtSelection.EndOfDocument(true);
       objBuildOutputWindowPane.OutputString(System.DateTime.Now.ToString());
       txtSelection = txtOutput.Selection;
       var solutionDir = System.IO.Path.GetDirectoryName(_applicationObject.Solution.FullName);
       System.IO.File.WriteAllText(solutionDir + "\\build_output.log", txtSelection.Text);
   }
   
   public void OnDisconnection(ext_DisconnectMode disconnectMode, ref Array custom)
   {
       if (buildEventConnected)
       {
           _buildEvents.OnBuildDone -= new _dispBuildEvents_OnBuildDoneEventHandler(BuildEvents_OnBuildDone);
           buildEventConnected = false;
       }
   }
   

That's it, on every build you'll have the output sent to the build_output.log file in your solution's folder.