Reading Command line build logs into the Visual Studio build output window

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Introduction

Although the Visual Studio IDE is a convenient way to develop applications, sometimes a better way to do builds is on the command line. This can often be easier and faster. However, if there are errors (or warnings), it would be nice to be able to fix these using the IDE. There didn't appear to be any way to load the build log files into Visual Studio, so I decided to write a macro to do this. I decided that this should either be invoked from the Tools menu, or by right clicking in the build window. This would ask for a file, which would be loaded into the build window. It would then be possible to view the source code associated with the error, either by double clicking it or by pressing F8, in exactly the same way as if the solution/project had been built within the IDE.

The Code

The code consists of a method which asks the user for a file to load, and reads the file line by line. Each line is then written to the output window as it is read. I decided to write a class for the output window. The constructor to this class takes a name, which in this case will be "build", but we could use names like "debug" or even specify a new name to create a new pane in the output window. The only service I have written in this class is Writeline which writes a line of text and then follows it with CR/LF. Other actions are achieved by accessing the Pane property, and calling services on this object.

Public Class NamedOutputPane
    Private win As OutputWindowPane
    Public ReadOnly Property Pane() As OutputWindowPane
        Get
            Return win
        End Get
    End Property
    Sub New(ByRef WindowName As String)
        win = Nothing

        ' Get an instance of the currently running Visual Studio .NET IDE.
        'The next two lines are required for AddIns but not for macros
        Dim DTE As EnvDTE.DTE
        DTE = System.Runtime.InteropServices.Marshal.    _
            GetActiveObject("VisualStudio.DTE")

        ' Create a tool window handle for the Output window.
        Dim mwin As Window = DTE.Windows.Item(EnvDTE.Constants    _
                        .vsWindowKindOutput)
        ' Create handles to the Output window and its panes.
        Dim OW As OutputWindow = mwin.Object
        Dim tmpOWp As OutputWindowPane

        'Look for the pane specified in "WindowPane"
        For Each tmpOWp In OW.OutputWindowPanes
            If tmpOWp.Name = WindowName Then
                win = tmpOWp
                Exit For
            End If
        Next
        If win Is Nothing Then
            ' Didn't find it - create a new pane
            win = OW.OutputWindowPanes.Add(WindowName)
        End If
    End Sub
    Sub OutputTextLine(ByRef txt As String)
        ' Add a line of text to the new pane.
        win.OutputString(txt)
        win.OutputString(vbCr)
    End Sub
End Class

The other method that I needed, that I wrote as a stand alone function, was to bring up a file open dialog, and ask for the name of the log file to read. This returns the name selected or Nothing if cancel was pressed. This uses the class WinWrapper in order to find the parent window. If you don't do this, the dialog won't always get the focus, and may be hidden behind the main window. I found this code in the sample macros.

Function AskForFileName() As String

    Dim winptr As WinWrapper = New WinWrapper
    Try
        Dim openfile As Forms.FileDialog = New Forms.OpenFileDialog
        If openfile.ShowDialog(winptr) = Forms.DialogResult.OK Then
            AskForFileName = openfile.FileName
        End If
    Catch err As System.Exception
        MsgBox(err.Message)
    End Try

End Function

And then finally the main method. Having done all the groundwork, all that needs to be done is to call the getname function and read the file line by line. Each line is written to the output window as it is read.

Sub ReadLogFile()

    Dim FileName As String = AskForFileName()

    If Not FileName Is Nothing Then

        'Get a handle to the "build" pane in the output window
        Dim OutWin As NamedOutputPane = New NamedOutputPane("Build")
        OutWin.Pane().Activate()    'Activate it
        OutWin.Pane().Clear()       'Clear it

        'Read the log file
        Dim sr As StreamReader = New StreamReader(FileName)

        Try
            Dim line As String
            ' Read and display the lines from the file until the end 
            ' of the file is reached.
            Do
                line = sr.ReadLine()
                OutWin.OutputTextLine(line)
            Loop Until line Is Nothing
            sr.Close()

        Catch E As Exception
            ' Let the user know what went wrong.
            OutWin.Pane().OutputString("The file could not be read:")
            OutWin.OutputTextLine(E.Message)
        End Try
    End If

End Sub

And that's it! All that remained was to add it to the Tools menu and the context (right mouse) menu. I did this by making it an add-in. The Tools menu option I did by selecting the right option in the wizard, and the right mouse menu is done using the following code:

'1+2 == vsCommandStatusSupported+vsCommandStatusEnabled
CommandObj = applicationObject.Commands.AddNamedCommand(objAddIn, _
         "ReadLogFile", _
        "Read Log File", _
        "Read log from file into build window", _
        False, 101, Nothing, 1 + 2)
CommandObj.AddControl(applicationObject.CommandBars.Item("Tools"))
CommandObj.AddControl(applicationObject.CommandBars. _
                    Item("Output Window Pane"))

The errors and warnings behave just as if the code had been built within the IDE, so the code can be viewed by double clicking on the error, pressing F8 etc.

History

• 01 Jan 2004 - Initial version.