I’m Eric Tummers, Technical Consultant at Valid, and this is how I work

I’m hired as a Software Architect to build a solution with Microsoft products. Our team works by the scrum guide and is moving towards continuous deployment. We are learning and growing while delivering business value. This is hard work. Every sprint we complete means the retrospective is done in the pub.

I expect the best and I give the best. Here’s the beer. Here’s the entertainment. Now have fun. That’s an order!

Location: Sittard, NL
Current Gig: Technical Consultant, Valid
Word that best describes how you work: Teamwork
Current mobile device: iPhone se
Current computer: MacBook 15 inch

What apps/software/tools can’t you live without? Why?

Wunderlist: work tasks, chores, groceries, planning, every task is there.
Evernote: I’m a fan for years now. Not to happy about the recent update but time will improve this.
iSmoothrun: when I’m not working, I’m running, this app tracks just about every metric I can think of and shares it to all the platforms (runkeeper for one)
Parallels 11: Running Windows on my MacBook is a must. And of course visual studio, team foundation server, build, release manager, sql server management studio, remote desktop, powershell, and some other tools I need for work.

What’s your workspace setup like?

Work at the office is on a thin client with 21 inch screen and (wired) mouse and keyboard. The desk and chair comply with all regulations. We have a great coffee machine.


My home workspace has moved to the kitchen table with my Macbook 15 inch. No externals and enough battery for the whole day. Freedom!

What’s your best time-saving shortcut/life hack?

Timebox. Start on a task and spent the time you’ve got to get the best result. Get someone to look at it, get feedback. Then decide if the result is final or to spent some more time.

Besides your phone and computer, what gadget can’t you live without and why?

I’ve been running with my Magellan Echo for some time. It is a sports watch that hooks up to my phone by bluetooth to start / stop my runs, control the music and see the metrics right on my wrist. It is powered by a battery that lasts 6 months and is easy to replace.
My Apple TV2 (jailbroken) hooked up to my NAS for movies and series. Also hooked to my stereo for music streaming. Awesome device!

What everyday thing are you better at than everyone else? What’s your secret?

Learning new things. My current project lets me implement new things (joy) Also I try to learn the things I know to my team or anyone who listens.
I have a basic understanding of how things work and try to map new things on there. For the details I have a Pluralsight subscription and black belt google skills.

What do you listen to while you work?

My alarm clock plays classical music to wake me up in the morning. The car stereo plays about everything (grunge, rock, kids stories) driving to work. When I need some focus I play drum and bass on my headphones. My ringtone is still Run riot by Camo & Krooked.

What are you currently reading?

Tools of Titans by Tim Ferriss. A Christmas gift. Best described as a book of “How I Work” posts full with tips and tricks of the titans (experts)


How do you recharge? What do you do when you want to forget about work?

Spending quality time with my wife and daughters. Phone on silent, no screens, no work. Mostly piggyback riding and thee parties
Also sports like running, fitness, climbing and snowboarding to keep me fit and healthy.

Fill in the blank: I’d love to see _________ answer these same questions.

Iris Classon, because she had to start from zero with her career shift and is now a Microsoft MVP (Most Valuable Professional).

What’s the best advice you’ve ever received?

someecards.com - Make a shit first draft you cannot edit a blank page
I believe this is a variant on a Hemingway quote.

Is there anything else you’d like to add that might be interesting to readers?

Learn Powershell. There is so much possible with Powershell. If you can learn one thing this year pick Powershell. 

Original idea from Lifehacker.com.

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Renew certificate 2017 edition

Today I used my trusty post Resolve certificate error for Synology Diskstation part 3 of 4 again to renew my certificate. The site startssl.com is still alive, is still free and still works. They even send me a reminder 2 weeks in advanced of the certificate expiring.

Uploading the certificate caused my browser to throw errors. The certificate was not trusted. Not happy 😦

There was some turbulence since last autumn. I totally mist this.

I need another (free) SSL source.

After some searching I ended up using sslforfree.com since I could verify my domain by adding a TXT-record. Other sites needed me to host files or open ftp to them with username and password 😯

To verify my domain using a TXT-record I noticed the google support page was not providing the right solution. The DNS entry should have _acme_challenge for the Host name:

Type Host Value TTL
TXT-Record _acme_challenge R4nD0m57R1n9 1 min

The provided certificate is valid for 90 days. Safari trusts this CA and the certificate. I’m happy again. 🙂

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Workaround for excluding assemblies from code coverage in TFS2015 build

Our build server is TFS2015 and Microsoft promises that we can customize code coverage analysis. But with runsettings setup to exclude assemblies from code coverage exceptions fail the build. Not nice.

Today we figured out how to work around this and exclude an assembly from code coverage. The key was in the msdn article; the pdb file was needed to get code coverage. Would this mean that when the pdb file was not there no code coverage was registered?

The assembly we wanted to exclude was Common.Logging. The nuget includes the pdb file for debugging purposes. We’re about to delete it in our build sequence:



The delete files step removes the Common.Logging.pdb before the Visual Studio Test step. Now the code coverage is not calculated for Common.Logging. Mission accomplished.

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Syncfusion grid datetime format fixed

We use the data grid from Syncfusion and it is awesome! It serialises the data on the server and puts it in the page as json. Now more postbacks to get extra data or for sorting / filtering / other expected user feature.

Unfortunately the formatting of datetime field was broken in the version we are using. After some digging we found that altering the json serialisation would fix the issue. See code below

using Newtonsoft.Json;
using Newtonsoft.Json.Converters;
using Syncfusion.JavaScript.Shared.Serializer;
using System;

namespace Utils {
    /// <summary>
    /// big data serializer, uses Newtonsoft.Json to get over 4Mb limit
    /// and serializes datatime fields for easy formatting
    /// </summary>
    public class BigDataSerializer : IDataSourceSerializer {
        // format DateTime as milliseconds from 1-1-1970 (java thing)
        public class MyDateTimeFormat : DateTimeConverterBase {
            public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) {
                var milliseconds = ((DateTime)value).Subtract(new DateTime(1970, 1, 1)).TotalMilliseconds;
                writer.WriteRawValue(string.Format("new Date({0})", milliseconds));

            public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer) {
                throw new NotImplementedException();

        // uses the MyDateTimeFormat class
        public string Serialize(object obj) {
            var result = JsonConvert.SerializeObject(obj,
                                new MyDateTimeFormat());
            return result;

In the Razor file that uses the data grid we put the following code at the start. This makes sure the BigDataSerializer is used and DataTime is formatted correct.

    Syncfusion.JavaScript.Shared.Serializer.DataManagerConverter.Serializer = new Utils.BigDataSerializer();
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Effort: Unhandled exception while trying to initialize the content of Table

We use Effort with the CsvDataLoader in our integration tests. After adding a new data file we got an exception.

unhandled exception while trying to initialize the content of table

On the forum every thread ended with something like “my bad” or “never mind”. Looking closer to my csv file showed the error: a typo in the header. The header contains the fields and they must match the fields in the table. After correcting the column header to dentDatabaseKey everything worked again.

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Continuous deployment step by step

This is not a how-to blog post guiding you to DEVOPS heaven. I write down the steps we are taking to get continuous deployment in place for our project. Every time we take another step I’ll update this post.

First of all: what are we aiming at?

We do our project using scrum. Product owners, scrum master and developers form the team. Like most projects we struggle with things like build, release and automated tests. Things scrum assumes to be just there. What do we want our continuous deployment to do?

Continuous deployment for us is being able to get the software build, deployed and tested without user interaction.

TFS 2015 with the scrum template is the tooling we use. TFVC is the version control. Build will create the software and do the unit testing. Release Management handles the deployment.

Step by step

Below is a schema of the proces we have in place now.


1. Build

First we created a build definition that pulls the sources from version control and puts the software on a drop location. During the build the unit tests are run. This was created the first week of the project.

We created / configured the proces for the build in the project portal. The supplied Visual Studio template was a good start. After a few days we added some steps like a powershell to update the assembly version with the build number.

2. Release

With the build creating software on the drop location we started creating the release pipelines. Installation of the software is done with DSC.

All developers (and testers) now have the tooling to start a release. Everything is triggered manually, but that will soon change.

3. Schedule

In the build definition we setup the trigger to scheduled every night. Now we have a nightly build.

4. Auto deployment

Together with the nightly build we added another step to the build that triggers the release of that build. This is done with an API call. Now we have new software on our server every morning.

Next steps

We plan to include test manager in the mix. After the auto deployment the integration tests are run and a report is waiting our team in the morning.



You might notice that this post is really superficial and not of much use when you run into trouble. Since every project is different and google-is-your-friend, I’m sure you’ll manage.

My post describes the steps we (you) need to take to get continuous deployment implemented in the project. I think multiple small steps are better than one huge leap. In the end we need to add business value by writing software. Sometimes the tooling gets in the way of that.

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WPF Toolkit DateTimePicker customisation of header

In my previous post WPF Toolkit PropertyGrid direct update I’ve written about getting the Property Grid from the WPF toolkit. Now I want to tell you about how I got the DateTimePicker to behave my way.

First of all the DateTimePicker is well documented. It offers a lot of properties, methods and events. Samples and solutions are available. But when I use it, it looks like the image below on the left. The header is to small and makes the text unreadable.


Calendar with header too small


Calendar the way I like it

After reading a lot of suggestions online I created a customised version of the control that increases the header. That makes the text readable again. The code below hooks into the OnApplyTemplate event from the control and registers for the loading of the child controls. When (finally) the Calendar is loaded the header is adjusted by using the PART_xxx templates provided by Microsoft.

public class CustomDateTimePicker : Xceed.Wpf.Toolkit.DateTimePicker {
    public override void OnApplyTemplate() {
        // 1. Look for the Popup (that holds the calendar)
        var popup = Template.FindName("PART_Popup", this) as Popup;
        popup.Loaded += Popup_Loaded;

    private void Popup_Loaded(object sender, RoutedEventArgs e) {
        // 2. When popup is loaded find the Calendar control/part
        var cal = Template.FindName("PART_Calendar", this) as Calendar;
        cal.Loaded += Cal_Loaded;

    private void Cal_Loaded(object sender, RoutedEventArgs e) {
        // 3. When calendar is loaded alter the header
        var cal = sender as Calendar;
        var calItem = cal.Template.FindName("PART_CalendarItem", cal) as CalendarItem;
        var header = calItem.Template.FindName("PART_HeaderButton", calItem) as Button;
        // 4. Finally ...
        if (header != null) {
            header.Height = 30;
            header.Width = 120;

In the Resolve editor method (see previous post) I create a CustomDatePicker, set some properties and bind it to the value. Code collapsed below. Now the DateTimePicker behaves my way.

public class InstantUpdatingDateTimePicker : ITypeEditor {
    public FrameworkElement ResolveEditor(PropertyItem propertyItem) {
        var dateTimePicker = new CustomDateTimePicker {
            BorderThickness = new Thickness(0),
            AllowSpin = false,
            AllowTextInput = false,
            ShowButtonSpinner = false,
            TimePickerShowButtonSpinner = false,
            AutoCloseCalendar = true

        var _binding = new Binding("Value"); //bind to the Value property of the PropertyItem
        _binding.Source = propertyItem;
        _binding.ValidatesOnExceptions = true;
        _binding.ValidatesOnDataErrors = true;
        _binding.Mode = propertyItem.IsReadOnly ? BindingMode.OneWay : BindingMode.TwoWay;
        _binding.UpdateSourceTrigger = UpdateSourceTrigger.PropertyChanged;


        return dateTimePicker;
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