Dan Miser

Powershell for Scheduled Tasks

Dan Miser — Fri, 27 Apr 2012 13:36:50 GMT

I needed a way to get a list of specific scheduled tasks running on a server. The main problem is that the command-line tool, schtasks.exe, is horrid. There is no ability to filter data. You get all of the data, or you get none. This is the Powershell script that I eventually settled on after piecing together a bunch of StackOverflow and blog entries. The key is the convertfrom-csv cmdlet that turns the result into objects that can be queried on, instead of a list of strings.

It's my first time using Powershell, and I don't know quite what to think. While it helped me solve my objective, and is quite powerful and extensible, it just doesn't feel natural to me. I'm sure that would change over time if I decide to invest time and energy to grok it. If anyone knows of a less awkward LINQ syntax, please let me know because that would turn me around on Powershell in a heartbeat.

 schtasks
/query /v /fo:csv | convertfrom-csv | where {$_.'Task To Run' -like '*MyProcess.exe*'
}

MonoTouch

Dan Miser — Sat, 10 Mar 2012 01:48:03 GMT

There is no way I can list everything I learned with MonoTouch over the last couple of months. I'll summarize my experience by saying I'm a very happy customer. There were bumps and bruises along the way, but between the mailing list and the support crew at Xamarin, I heartily recommend investigating MonoTouch if you're a .NET developer that wants to get to the iOS AppStore quickly. I had to take several detours along the way (converted my existing app from Lightspeed to EF4 CodeFirst, converted to use POCOs, had support obligations, and wrote a sync engine to communicate over ServiceStack, but in the end, things lined up pretty well.

Some of the highlights:

I had to write code to essentially mimic the context loading that EF would do for you. This included fixing up object references as well as reading and writing from the SQLite database. Not horribly difficult, but it was something I'd rather I didn't have to do.
I encountered a couple of problems executing various LINQ statements when running on the device. A quick test case, and the devs at Xamarin had me with either workarounds or fresh bits to solve my problems.
Be sure to embrace threading when making web calls - especially on startup. You have 15 seconds to have your app launched on the device, or the device will think it is hung and kill the app.
Deploying to the app store has been written about extensively as a complex and intricate process. It turns out, there's good reason for that. After I got through an error due to linking my release build to ServiceStack.Text.dll, the resulting upload to the app store was failing verification. For some reason, the application name of RouteBoostiPhone.app was not being accepted. I changed the name to RouteBoost.app and it sailed right through. I have no idea exactly why this was required, but there you have it.
MonoTouch.Dialog is a very nice framework for building a line of business app. Be sure to check it out.

When I look back on the road I travelled to get my app to the app store, I'm impressed with how much of the business logic I was able to carry over. The time savings in being able to bring my business logic across as POCOs that have been extensively tested in production over many years was the real reason I went with MonoTouch to begin with. I most definitely do not regret that decision.

Note: I was not compensated or asked to write this post. I am just a happy paying customer of a product that saved me time, and I wanted to share my experience.

VMWare Fusion Tips and Tricks

Dan Miser — Wed, 29 Feb 2012 00:37:46 GMT

The iPhone app that I'm writing uses ServiceStack to communicate with an existing ASP.NET MVC app that I've had in production for a long time. The way I have things set up is that I'm doing my iPhone development on MonoTouch on the Mac side, and I use VMWare Fusion to run Windows as a guest OS. This blog will highlight a few of the tips that I found to be handy.

Getting IIS Express to work from an external server (even the Mac OS host) is theoretically possible. I found articles lying around the net saying it could work, but it never worked for me. I ended up going back to Cassini (WebDev.WebServer40.exe) and using tcpTrace to listen externally on port 8080 and forwarding to my local port (e.g. 1234).
In order to get VMWare Fusion using NAT to talk to my Windows OS on a consistent IP address, I added this section at the bottom of /Library/Preferences/VMware Fusion/vmnet8/dhcpd.conf (replacing the MAC address of the Macintosh and the IP address from the Windows machine)
```
 host winguest { hardware ethernet xx:xx:xx:xx:xx:xx; fixed-address 172.16.123.123;
} 
```
In order to get external devices (e.g. my iPhone connected to the same wireless network) to see in to the Windows OS, I set up port forwarding to route requests coming in to the Mac on port 80 to point to port 8080 on the Windows machine. I did this by modifying this section in /Library/Preferences/VMware Fusion/vmnet8/nat.conf:
```
 [incomingtcp] 80 = 172.16.123.123:8080 
```

After all of that, I can communicate from my iPhone through my Mac into the VMWare-hosted Windows machine to get at the data.

Downloading from within an AJAX form

Dan Miser — Sun, 19 Feb 2012 17:33:35 GMT

I have an HTML form that allows users to fill out a bunch of different parameters, and then it will display the result on the same page via an AJAX call. Pretty standard, and it works great. I had a request to allow for exporting the data in Excel format. Unfortunately, just returning a File ActionResult won't work from within the context of an Ajax form. There were some workaround posted out there (e.g. hidden iframe, duplicate the form on the page, etc.). I found the following approach to be a nice compromise and DRYs things up considerably. The key is that by putting the onclick on the Export button to do this.form.submit(), it forces the request to be a standard POST and not an AJAX call.

View.cshtml

 @using(Ajax.BeginForm("ReportData", new AjaxOptions {UpdateTargetId="result"}))
{ ... other input elements here <input type="submit" value="Display" /> <input
type="submit" value="Export" onclick="this.form.submit();"> }

Controller.cs

 public ActionResult ReportData(... parameters go here ...) { if (Request.IsAjaxRequest())
{ // Do the normal behavior here to build up a string return Content(s); } // I actually
stream the result with a custom ExcelResult action, // but this shows how to just
return a file. return File(@"c:\library\report.xls", "application/vnd.ms-excel");
}

Entity Framework CodeFirst: virtual is sort of important

Dan Miser — Wed, 15 Feb 2012 00:55:59 GMT

I had a class that looked like this:

 public class CollectionDetail { public int Id { get; set; } ... public
MachineField MachineField { get; set; } }

I would then later write LINQ code that would end up retrieving these objects. The problem was MachineField was always set to null. I banged my head on this for a long time looking at everything I could think of. Finally, after looking at the CollectionDetail class one more time, I noticed that other Foreign Key objects were marked with virtual, and I remembered that I removed virtual while I was trying to test whether or not the object's lazy load behavior. All of the documentation clearly states that you need to mark this virtual. Once I added the virtual keyword back, everything worked exactly as it should have.

ActionSheetDatePicker enhancements

Dan Miser — Sun, 22 Jan 2012 18:13:42 GMT

I found the class ActionSheetDatePicker from the book Developing C# Apps for iPhone and iPad using MonoTouch iOS Apps Development for .NET Developers. It was a very nice and clean implementation that would allow for having an ActionSheet pop up with a UIDatePicker in an iOS application.

It did lack 2 things, though:

The ability to specify a starting default date in the UIDatePicker
The ability to get cleanly launched from a UITextField component (i.e. effectively replace the default keyboard of a text field with this date picker). The original code would leave the default keyboard up when getting called from a UITextField component.

I fixed those things, and you can find the results in this gist.

The Award For Most Useless Overloaded Method Ever Goes To...

Dan Miser — Sun, 15 Jan 2012 15:52:59 GMT

What's the difference between these 2 methods?

 Html.ActionLink(string
linkText, string actionName, object routeValues, object htmlAttributes) Html.ActionLink(string
linkText, string actionName, RouteValueDictionary routeValues, IDictionary htmlAttributes)

Yes, they have the same number of parameters. Yes, they even have the same parameter names. So in essence the intent of calling either of these methods is to build up a link with the passed in route values and HTML attributes. Yet the difference between these 2 methods couldn't be more pronounced.

Take this line of code:

 @Html.ActionLink("Back to List", "Index", TempData["SavedRouteValues"],
null)

What I wanted was an easy way to retain the settings of a Telerik ASP.NET MVC Grid and build up a link to bring me back to the correct state. This line of code does that. However, it generates a link similar to this (word-wrapped here for clarity):

 http://www.foo.com/Grid?Count=3&Keys=System.Collections.Generic.Dictionary%602%2BKeyCollection%5BSystem.String%2CSystem.Object
%5D&Values=System.Collections.Generic.Dictionary%602%2BValueCollection%5BSystem.String%2CSystem.Object%5D

Brutal. Ugly.

To fix this, just use this code (a simple typecast) to force the correct overloaded method to be picked:

 @Html.ActionLink("Back to List", "Index", (RouteValueDictionary)TempData["SavedRouteValues"],
null)

The moral of the story? If you're an API desiger, don't make overloaded methods lightly. Make sure they add value and distinction. A strong type vs. an object reference doesn't pass that test. If you do violate that rule, however, then at least be sure that the overload fulfills the intent and implied contract of that method.

Message banners in ASP.NET MVC

Dan Miser — Sun, 08 Jan 2012 22:33:36 GMT

Martijn Boland provides us with a nice way to display message banners in an ASP.NET MVC application. I highly recommend checking out his blog post and code sample.

ServiceStack and MonoTouch

Dan Miser — Thu, 08 Dec 2011 21:27:12 GMT

My company's core applications are written in ASP.NET MVC, and have been well received. But the nature of what those applications can do in limited/non-existent connectivity areas is causing enough problems that I need a native iPhone solution. (HTML 5 offline storage is not enough. I need full access to the brains of calculation engines that are in my business logic on the server, and I wouldn't relish moving that logic to JavaScript. Besides, I found a real nice thermal receipt printer that will work via SDK with a native app!)

I came across MonoTouch, and I really like how it will enable reuse of my hard work over the years. The main obstacle for me was how to get the data out to my iPhone client. I wasn't exactly thrilled with the idea of shoe-horning WCF access from the iPhone, and working with WCF at my day job is a configuration nightmare. REST would be good, but I wasn't happy with the options out there - until I found ServiceStack. I don't know why this thing doesn't get more publicity. It is everything I want: small, fast, actively developed, easy to configure, JSON, REST, DTOs, and works easily with MonoTouch. Well done, guys.

The first snag I hit getting some demo code out there was that if you want to have the client code exist on MonoTouch, be sure to add references to the assemblies found in the MonoTouch-v2.20.zip file on github. I'm curious why this is still labelled as 2.20, and why those assemblies are still dated from June 9, 2011, but for now, things are moving along to convert my ASP.NET MVC application to use services, and expose those services for use on my iPhone client.

Look for more posts about ServiceStack and MonoTouch in the near future.

Upgrading Snow Leopard to Lion with Windows 7 Bootcamp

Dan Miser — Fri, 28 Oct 2011 16:21:50 GMT

I've read enough horror stories about upgrading Snow Leopard to Lion causing corruption of the Windows 7 partition, and I didn't want to be yet another casualty. So I took the time to research how best to backup in order to prepare myself in case something went wrong.

I started by cloning the Mac OSX partition to an external USB drive using Carbon Copy Cloner. This was drop dead simple, and worked well. There's a complete writeup of this here.

I couldn't get the Mac Disk Utility to clone the bootcamp partition. It would error out with an "Invalid Argument" message. I found a version of WinClone 2.3.2, but that also gave me errors. I finally got it to work by unchecking all of the options in the Preferences window, thanks to comments in this article. I also made sure the USB partition that I was backing up to was set to Mac OS Extended (Journaled). After that, it was a painless clone process.

The actual Lion upgrade went smooth. I didn't lose anything, and everything just worked. One quick note is that you might want to save a backup of the Lion installer if you have multiple Macs that you'll be upgrading. Details on how to do that can be found here.

Off to install MonoTouch for iOS!!