My name is Edward Tanguay. I'm an American software and web developer living and working in Berlin, Germany.

2 days ago: Posted new ObservableCollection MenuItem w/ TextBox, ItemContainerStyle, still doesn't work, but now in a different way: http://is.gd/1l58e.

2 days ago: Has anyone doing WPF successfully bound MenuItems to an ObservableCollection, looking for a working code example: http://is.gd/1l58e.

2 days ago: Video: what if JFK had been a CEO, speaker is my former roommate from college, lucid and entertaining as back in the day: http://is.gd/1l4fl.

3 days ago: Informative podcast on sharepoint with Sahil Malik, requires AD?, must run in VM?, no debugging? sounds cumbersome: http://is.gd/1jFz1.

4 days ago: Got SQLite installed and running on Debian VPS, here's how: http://is.gd/1iL68.

4 days ago: Purchased and set up a VPS within an hour on a Sunday afternoon, nice experience so far: http://www.server4you.de.

4 days ago: Podcast by Kevin Kelly on the future of the web, "cloud applications, all about data, wholly different than today's web": http://is.gd/1iKtr.

4 days ago: Enjoyable, 2-beer podcast, @shanselman, Franklin et al. get rolling, funny, pub-atmosphere geek talk, win7, surface, etc. http://is.gd/1iKbP.

4 days ago: If you compose music, check out: http://www.ableton.com, good example of a simple and effective product demo video, 12 min. riveting.

5 days ago: Anyone know how I can post-install SQLite on a Suse VPS with automatic Apache/PHP setup? http://is.gd/1hm6X.

on Wednesday, June 24, 2009: C# CODE EXAMPLE: Three ways to create the same XML file (string concat, xmlwriter, linq-to-xml): http://is.gd/1ctco.

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C# CODE EXAMPLE created on Thursday, June 25, 2009 permalink

Four ways to create an XML file

Here are four ways to create the same XML string that I needed for an application: string concatenation, XmlWriter, LINQ-to-XML, in reverse order of preference (plus an example using XML literals which Jim Wooley posted on his site along with some notes on the dangers of string concatenation). These code samples assume an object called DataType which is not included in the code, so the code isn't executable as is, but I just wanted to record the syntax of each way for further reference. Notice the Enumerable.Range(1, 3).Select on the LINQ-to-XML functions as a for loop.

String Concatentation:

    StringBuilder sb = new StringBuilder();
    sb.Append("<?xml version=\"1.0\" encoding=\"utf-8\"?>" + Environment.NewLine);

    sb.Append(String.Format("<{0}>{1}", _pluralCamelNotation, Environment.NewLine));
    for (int index = 0; index < 3; index++)
    {
        sb.Append(String.Format("\t<{0}>{1}", _singularCamelNotation, Environment.NewLine));
        foreach (DataType dataType in _allDataTypes)
        {
            sb.Append(String.Format("\t\t<{0}>{2}</{0}>{1}", dataType.CamelCaseNotation, Environment.NewLine, dataType.GetDummyData()));
        }
        sb.Append(String.Format("\t</{0}>{1}", _singularCamelNotation, Environment.NewLine));
    }
    sb.Append(String.Format("</{0}>{1}", _pluralCamelNotation, Environment.NewLine));

XmlWriter:

            XmlWriterSettings settings = new XmlWriterSettings();
            settings.NewLineHandling = NewLineHandling.Entitize;
            settings.Indent = true;
            settings.IndentChars = "\t";

            StringBuilder sb = new StringBuilder();
            using (XmlWriter xw = XmlWriter.Create(sb, settings))
            {
                xw.WriteStartDocument();
                xw.WriteStartElement(_pluralCamelNotation);
                for (int i = 0; i < 3; i++)
                {
                    xw.WriteStartElement(_singularCamelNotation);
                    foreach (DataType dataType in _allDataTypes)
                    {
                        xw.WriteElementString(dataType.CamelCaseNotation, dataType.GetDummyData());
                    }
                    xw.WriteEndElement();
                }
                xw.WriteEndElement();
                xw.WriteEndDocument();
                xw.Close();
            }
            return sb.ToString();

XML Literals (VB.NET):

        Dim doc = <?xml version="1.0"?>
                    <<%= _pluralCamelNotation %>>
                        <%= From i In Enumerable.Range(1, 3) _
                            Select <<%= _singluarNotation %>>
                                     <%= From t In _allDataTypes _
                                         Select <<%= t.CamelCaseNotation %>>
                                             <%= t.GetDummyData %></> %>
                                 </> %>
                    </>

LINQ-to-XML:

            XDocument doc = new XDocument(
                new XDeclaration("1.0", null, null),
                new XElement(_pluralCamelNotation,
                    Enumerable.Range(1, 3).Select(
                        i => new XElement(_singularCamelNotation,
                            _allDataTypes.Select(
                                dataType => new XElement(
                                    dataType.CamelCaseNotation,
                                    dataType.GetDummyData())
                            )
                    ))));
            return doc.ToString();

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WPF CODE EXAMPLE created on Wednesday, June 24, 2009 permalink

WPF/MVVM application with dynamic menu and buttons

This is a base WPF application with a View/ViewModel pattern and no code-behind, it loads the pages from an XML file. To create a new page you need to make a new entry in the XML, create a View and a ViewModel and it will automatically appear. The MainView is injected into each ViewModel so that each ViewModel can have buttons which go to other pages, there is an example of this on the Options page.

> > > Download Code

MainView.xaml:

MainViewModel constructor:

        public MainViewModel()
        {

            PageItems pageItems = PageItems.Create("all");

            foreach (PageItem pageItem in pageItems.Collection)
            {
                string assemblyName = System.Reflection.Assembly.GetExecutingAssembly().GetName().Name;
                string viewModelName = assemblyName + ".ViewModels.PageItem" + StringHelpers.ForcePascalNotation(pageItem.IdCode) + "ViewModel";
                var type = Type.GetType(viewModelName);
                var viewModel = Activator.CreateInstance(type, this, pageItem) as ViewModelPageItemBase;
                AllPageItemViewModels.Add(viewModel);
            }

            CurrentPageItemViewModelIndex = 0;
            LoadCurrentPageItemViewModel();
        }

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WPF CODE EXAMPLE created on Tuesday, June 23, 2009 permalink

How to create a WPF/MVVM application with dynamic menu

This application loads an XML file of "PageItems" which fill an ObservableCollection in the MainViewModel which builds a Menu dynamically. The user can also change the pages with a slider or by clicking the previous and next buttons. The title of the page is displayed at the bottom as well. For some reason when the user clicks on the icon area of the menu item, the DelegateCommand is not fired. I asked about the menu item issue on StackOverflow.

> > > Download Code

MainView.xaml:

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WPF CODE EXAMPLE created on Saturday, June 20, 2009 permalink

How to use MVVM pattern to validate an e-mail field as the user types

Most books would show you how to validate a field as the user is typing by creating a TextBox then adding a TextChanged event and handling that event in the code behind, or using a Validator class. However, if you are using the MVVM pattern, you can basically forget this since you don't want your code-behind side-stepping your ViewModel to get information from the database, etc. Instead, you need to bind the text of your TextBox to a property on your ViewModel like this Text="{Binding FieldEmail, UpdateSourceTrigger=PropertyChanged}"> and then attach a style to the TextBox which has DataTriggers that change the color based on another property on your ViewModel. This works well, is fully MVVM compliant, no code-behind.

> > > Download Code

XAML:

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MVVM CODE EXAMPLE created on Friday, June 19, 2009 permalink

How to bind multiple XAML controls to one ObservableCollection in your ViewModel

This was an experiment to get control of how to bind various controls (ComboBox, ListBox, Slider) to one ObservableCollection (Customers) in the ViewModel. You can also add a new Customer by typing in a first and last name and only when both are filled out will the button be enabled. There is no code-behind in this example, all is being done with binding. When you move one control all others move as well.

> > > Download Code

XAML:

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WPF CODE EXAMPLE created on Friday, June 19, 2009 permalink

Three ways to format dates in a XAML DataTemplate

Just wanted to record these three ways of formatting dates, basically you can use StringFormat in the same way you do in code in this way, also see my example of MultiBinding which uses StringFormat.

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WPF CODE EXAMPLE created on Thursday, June 18, 2009 permalink

How to access objects and their properties within Observable collections

This was an experiment to find the syntax to access e.g. a particular property of a particular customer within a collection and determine some UI effect based on the value. Notice you get the Status of the first customer object with this: {Binding Customers[0].Status}.

> > > Download Code

View:

ViewModel:

        public MainViewModel()
        {
            LoadCustomers(1);
        }

        private void LoadCustomers(int sortOrder)
        {
            Customers.Clear();

            if (sortOrder == 1)
            {
                Customers.Add(new Customer { FirstName = "Jim", LastName = "Smith", Status = "waiting" });
                Customers.Add(new Customer { FirstName = "Joe", LastName = "Jones", Status = "waiting" });
                Customers.Add(new Customer { FirstName = "Jack", LastName = "Alard", Status = "approved" });
            }
            else
            {
                Customers.Add(new Customer { FirstName = "Jack", LastName = "Alard", Status = "approved" });
                Customers.Add(new Customer { FirstName = "Jim", LastName = "Smith", Status = "waiting" });
                Customers.Add(new Customer { FirstName = "Joe", LastName = "Jones", Status = "waiting" });
            }
        }

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WPF CODE EXAMPLE created on Thursday, June 18, 2009 permalink

How to access bound individual items in ObservableCollection from XAML

This shows an example of an instant translator for an application: a user can use a slider to switch between English and German whereby he instantly sees the text on every control be translated. Collection elements such as ListView are straight-forward and for single elements such as Button and TextBlock the syntax for accessing the desired object is {Binding Translations[0].Value} where "Value" can be any property on the object in the ObservableCollection.

> > > Download Code

XAML:

ViewModel:

using System.Collections.Generic;
using System.Collections.ObjectModel;
using TestObjectUpdate234.Models;

namespace TestObjectUpdate234.ViewModels
{
    public class MainViewModel : ViewModelBase
    {

        private ObservableCollection<TranslateTerm> _translations = new ObservableCollection<TranslateTerm>();
        public ObservableCollection<TranslateTerm> Translations
        {
            get
            {
                return _translations;
            }

            set
            {
                _translations = value;
                OnPropertyChanged("Translations");
            }
        }

        private int _languageIndex;
        public int LanguageIndex
        {
            get
            {
                return _languageIndex;
            }

            set
            {
                _languageIndex = value;
                OnPropertyChanged("LanguageIndex");
                FillTranslations();
            }
        }

        public MainViewModel()
        {
            _languageIndex = 0; //english
            FillTranslations();
        }

        private void FillTranslations()
        {
            if (_languageIndex == 0)
            {
                Translations.Clear();
                Translations.Add(new TranslateTerm { Key = "add", Value = "Add"});
                Translations.Add(new TranslateTerm { Key = "copy", Value = "Copy" });
            }
            else
            {
                Translations.Clear();
                Translations.Add(new TranslateTerm { Key = "add", Value = "Hinzufügen" });
                Translations.Add(new TranslateTerm { Key = "copy", Value = "Kopieren" });
            }

        }

    }
}

TranslateTerm.cs:

namespace TestObjectUpdate234.Models
{
    public class TranslateTerm
    {
        public string Key { get; set; }
        public string Value { get; set; }
    }
}

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WPF CODE EXAMPLE created on Thursday, June 18, 2009 permalink

How to access items in a (readonly) ViewModel Dictionary property

This example shows how you can have a ViewModel property that is a Dictionary of saw 200 items and in your view you can access each one with simple square bracket syntax. Unfortunately the Dictionary object is not updated as are string properties as this example shows. So this is a good solution if you need a readonly Dictionary that does not need to be further updated at runtime. For that, you would need to create an ObservableDictionary or find some syntax like this which allows you to access items in an ObservableCollection in the same way as you access them in a Dictionary.

> > > Download Code

XAML:

ViewModel:

using System.Collections.Generic;

namespace TestObjectUpdate234.ViewModels
{
    public class MainViewModel : ViewModelBase
    {

        private string _translationEdit;
        public string TranslationEdit
        {
            get
            {
                return _translationEdit;
            }

            set
            {
                _translationEdit = value;
                OnPropertyChanged("TranslationEdit");
            }
        }

        private Dictionary<string, string> _translations = new Dictionary<string, string>();
        public Dictionary<string, string> Translations
        {
            get
            {
                return _translations;
            }

            set
            {
                _translations = value;
                OnPropertyChanged("Translations");
            }
        }

        private int _languageIndex;
        public int LanguageIndex
        {
            get
            {
                return _languageIndex;
            }

            set
            {
                _languageIndex = value;
                OnPropertyChanged("LanguageIndex");
                FillTranslations();
            }
        }

        public MainViewModel()
        {
            _languageIndex = 0; //english
            FillTranslations();

        }

        private void FillTranslations()
        {
            if (_languageIndex == 0)
            {
                TranslationEdit = "Edit";

                Translations.Clear();
                Translations.Add("add", "Add");
            }
            else
            {
                TranslationEdit = "Bearbeiten";

                Translations.Clear();
                Translations.Add("add", "Hinzufügen");
            }

        }

    }
}

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C# CODE EXAMPLE created on Wednesday, June 17, 2009 permalink

How to get and set properties of an object dynamically with reflection

These two methods can be used on on object so that you can e.g. parse an XML file that has changes in it, and make changes on an object based on the strings in the XML file.

using System;
using System.Reflection;

namespace TestSetPropertyValue834
{
    class Program
    {
        static void Main(string[] args)
        {
            Customer customer = new Customer { Id = 1, FirstName = "Jim", LastName = "Smith" };

            Console.WriteLine(customer.LastName);
            Console.WriteLine(customer.GetPropertyValueAsString("LastName"));
            customer.SetPropertyValueWithString("LastName", "SmithChanged");
            Console.WriteLine(customer.GetPropertyValueAsString("LastName"));
            Console.ReadLine();
        }
    }

    class Customer
    {
        public int Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public int Age { get; set; }

        public string GetPropertyValueAsString(string propertyName)
        {
            PropertyInfo prop = typeof(Customer).GetProperty(propertyName);
            object value = prop.GetValue(this, null);
            return value.ToString();
        }

        public void SetPropertyValueWithString(string propertyName, string value)
        {
            PropertyInfo prop = typeof(Customer).GetProperty(propertyName);
            prop.SetValue(this, value, null);
        }
    }
}

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"The ViewModel exists intimately for the View but has no dependencies on the View."

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