How do I write to the Visual Studio Output Window in My Custom Tool?

Question

I am writing a custom tool and I currently have it doing what I want as far as functionality. I would like to be able to write to Visual Studio if something goes wrong. (Incorrectly formatted code or whatever).

Are there any standards for this? Right now I basically can force the tool to fail and Visual Studio puts in a warning that it has done so. I'd like a category in the Output window with any resulting messages I want to send. I could also live with a more descriptive task/warning in the Error list window.

Answer 1

Output Window

To write to the "General" output window in Visual Studio, you need to do the following:

IVsOutputWindow outWindow = Package.GetGlobalService( typeof( SVsOutputWindow ) ) as IVsOutputWindow;

Guid generalPaneGuid = VSConstants.GUID_OutWindowGeneralPane; // P.S. There's also the GUID_OutWindowDebugPane available.
IVsOutputWindowPane generalPane;
outWindow.GetPane( ref generalPaneGuid , out generalPane );

generalPane.OutputString( "Hello World!" );
generalPane.Activate(); // Brings this pane into view

If, however, you want to write to a custom window, this is what you need to do:

IVsOutputWindow outWindow = Package.GetGlobalService( typeof( SVsOutputWindow ) ) as IVsOutputWindow;

// Use e.g. Tools -> Create GUID to make a stable, but unique GUID for your pane.
// Also, in a real project, this should probably be a static constant, and not a local variable
Guid customGuid = new Guid("0F44E2D1-F5FA-4d2d-AB30-22BE8ECD9789");
string customTitle = "Custom Window Title";
outWindow.CreatePane( ref customGuid, customTitle, 1, 1 );

IVsOutputWindowPane customPane;
outWindow.GetPane( ref customGuid, out customPane);

customPane.OutputString( "Hello, Custom World!" );
customPane.Activate(); // Brings this pane into view

Details on IVsOutputWindow and IVsOutputWindowPane can be found on MSDN.

Error List

For adding items to the error list, the IVsSingleFileGenerator has a method call void Generate(...) which has a parameter of the type IVsGeneratorProgress. This interface has a method void GeneratorError() which lets you report errors and warnings to the Visual Studio error list.

public class MyCodeGenerator : IVsSingleFileGenerator
{
    ...
    public void Generate( string inputFilePath, string inputFileContents, string defaultNamespace, out IntPtr outputFileContents, out int output, IVsGeneratorProgress generateProgress )
    {
        ...
        generateProgress.GeneratorError( false, 0, "An error occured", 2, 4);
        ...
    }
    ...
}

The details of GeneratorError() can be found on MSDN.

Answer 2

There is another way using Marshal.GetActiveObject to grab a running DTE2 instance.

First reference EnvDTE and envdte80. This currently works in VisualStudio 2012, I haven't tried the others yet.

using System;
using System.Runtime.InteropServices;
using EnvDTE;
using EnvDTE80;

internal class VsOutputLogger
{
    private static Lazy<Action<string>> _Logger = new Lazy<Action<string>>( () => GetWindow().OutputString );

    private static Action<string> Logger
    {
        get { return _Logger.Value; }
    }

    public static void SetLogger( Action<string> logger )
    {
        _Logger = new Lazy<Action<string>>( () => logger );
    }

    public static void Write( string format, params object[] args)
    {
        var message = string.Format( format, args );
        Write( message );
    }

    public static void Write( string message )
    {
        Logger( message + Environment.NewLine );
    }

    private static OutputWindowPane GetWindow()
    {
        var dte = (DTE2) Marshal.GetActiveObject( "VisualStudio.DTE" );
        return dte.ToolWindows.OutputWindow.ActivePane;
    }
}

Answer 3

If you want anything to appear in the Output window, it has to come from stdout. To do this, your app needs to be linked as a "console" app. Set the /SUBSYSTEM:CONSOLE flag in the project's property page, under Linker/System set the SubSystem property to CONSOLE.

Once you have your output in the window, if you include the text "Error:" it will appear as an error, or if you set "Warning:" it will appear as a warning. If your error text begins with a path/filename, followed by a line number in parenthesis, the IDE will recognize it as a "clickable" error, and navigate you automatically to the faulting line.

Answer 4

This is demonstrated in the following helper class from a Microsoft sample project:

https://github.com/microsoft/VSSDK-Extensibility-Samples/blob/df10d37b863feeff6e8fcaa6f4d172f602a882c5/Reference_Services/C%23/Reference.Services/HelperFunctions.cs#L28

The code is as follows:

using System;
using System.Diagnostics;
using Microsoft.VisualStudio.Shell.Interop;

namespace Microsoft.Samples.VisualStudio.Services
{
    /// <summary>
    /// This class is used to expose some utility functions used in this project.
    /// </summary>
    internal static class HelperFunctions
    {
        /// <summary>
        /// This function is used to write a string on the Output window of Visual Studio.
        /// </summary>
        /// <param name="provider">The service provider to query for SVsOutputWindow</param>
        /// <param name="text">The text to write</param>
        internal static void WriteOnOutputWindow(IServiceProvider provider, string text)
        {
            // At first write the text on the debug output.
            Debug.WriteLine(text);

            // Check if we have a provider
            if (null == provider)
            {
                // If there is no provider we can not do anything; exit now.
                Debug.WriteLine("No service provider passed to WriteOnOutputWindow.");
                return;
            }

            // Now get the SVsOutputWindow service from the service provider.
            IVsOutputWindow outputWindow = provider.GetService(typeof(SVsOutputWindow)) as IVsOutputWindow;
            if (null == outputWindow)
            {
                // If the provider doesn't expose the service there is nothing we can do.
                // Write a message on the debug output and exit.
                Debug.WriteLine("Can not get the SVsOutputWindow service.");
                return;
            }

            // We can not write on the Output window itself, but only on one of its panes.
            // Here we try to use the "General" pane.
            Guid guidGeneral = Microsoft.VisualStudio.VSConstants.GUID_OutWindowGeneralPane;
            IVsOutputWindowPane windowPane;
            if (Microsoft.VisualStudio.ErrorHandler.Failed(outputWindow.GetPane(ref guidGeneral, out windowPane)) ||
                (null == windowPane))
            {
                if (Microsoft.VisualStudio.ErrorHandler.Failed(outputWindow.CreatePane(ref guidGeneral, "General", 1, 0)))
                {
                    // Nothing to do here, just debug output and exit
                    Debug.WriteLine("Failed to create the Output window pane.");
                    return;
                }
                if (Microsoft.VisualStudio.ErrorHandler.Failed(outputWindow.GetPane(ref guidGeneral, out windowPane)) ||
                (null == windowPane))
                {
                    // Again, there is nothing we can do to recover from this error, so write on the
                    // debug output and exit.
                    Debug.WriteLine("Failed to get the Output window pane.");
                    return;
                }
                if (Microsoft.VisualStudio.ErrorHandler.Failed(windowPane.Activate()))
                {
                    Debug.WriteLine("Failed to activate the Output window pane.");
                    return;
                }
            }

            // Finally we can write on the window pane.
            if (Microsoft.VisualStudio.ErrorHandler.Failed(windowPane.OutputString(text)))
            {
                Debug.WriteLine("Failed to write on the Output window pane.");
            }
        }
    }
}

Answer 5

You can use the Debug and/or Trace classes. There is some information here: http://msdn.microsoft.com/en-us/library/bs4c1wda(VS.71).aspx

Best of luck.

Answer 6

use System.Diagnostics.Debugger.Message