How to write a loop, or lambda expression, in the immediate window, part 2

$dte is the key.

That whole nuget package manager console window, that is a powershell window, that gives you easy access to the visual studio automation model, is neat, very powerful, and, as I have discovered, a treasure trove of Visual Studio arcana.

EnvDTE.DTE is easy to get at when you are in the context of an add-in that you have written yourself. Exposing it in ready made powershell window, is a complex and involved trick. Writing that whole powershell console as an add-in inside of Visual Studio, after reading the source code at nuget.codeplex.com, appears to be an elegant work of coding art.

But.. back to $dte, my favorite powershell-nuget-visualstudio variable. Here is the code that worked the magic and populated the variable inside of powershell:

http://nuget.codeplex.com/SourceControl/latest#src/VsConsole/PowerShellHost/RunspaceManager.cs

 

        [System.Diagnostics.CodeAnalysis.SuppressMessage(
            "Microsoft.Reliability",
            "CA2000:Dispose objects before losing scope",
            Justification = "We can't dispose it if we want to return it.")]
        private static Tuple CreateRunspace(IConsole console, string hostName)
        {
            DTE dte = ServiceLocator.GetInstance();

InitialSessionState initialSessionState = InitialSessionState.CreateDefault();
            initialSessionState.Variables.Add(
                new SessionStateVariableEntry(
                    "DTE",
                    (DTE2)dte,
                    "Visual Studio DTE automation object",
                    ScopedItemOptions.AllScope | ScopedItemOptions.Constant)
            );

// this is used by the functional tests
            var packageManagerFactory = ServiceLocator.GetInstance();
            var pmfTuple = Tuple.Create<string, object>("packageManagerFactory", packageManagerFactory);

Tuple<string, object>[] privateData = new Tuple<string, object>[] { pmfTuple };

var host = new NuGetPSHost(hostName, privateData)
            {
                ActiveConsole = console
            };

var runspace = RunspaceFactory.CreateRunspace(host, initialSessionState);
            runspace.ThreadOptions = PSThreadOptions.Default;
            runspace.Open();

//
            // Set this runspace as DefaultRunspace so I can script DTE events.
            //
            // WARNING: MSDN says this is unsafe. The runspace must not be shared across
            // threads. I need this to be able to use ScriptBlock for DTE events. The
            // ScriptBlock event handlers execute on DefaultRunspace.
            //
            Runspace.DefaultRunspace = runspace;

return Tuple.Create(new RunspaceDispatcher(runspace), host);
        }

 

Pasted from <http://nuget.codeplex.com/SourceControl/latest>

 

 

So here is what I learned from strolling down this rabbit hole.

1. They brute forced the whole console window. They didn't recycle any sort of existing powershell or command window. They wrote a new one and dealt with all the keypress by keypress nastiness that is involved therein.
2. $dte is actually spelled $DTE, and just a variable passed into a Runspace through its InitialSessionState.
3. OpenSource code is fun.

Also, and unrelated to codeplex and nuget, if you want to create a headless $dte object, or rather one connected to a new instance of visual studio 2012, that is simply:

$dte = New-Object -comobject VisualStudio.DTE.11.0

Getting the running obect is done like this:

$dte = [System.Runtime.InteropSrevices.Marshal]::GetActiveObject("VisualStudio.DTE.11.0")