WPF: How do I have to setup my model and the binding strategy ?

Question

Regard this image:

The TimeTableViewModel of this user interface is this:

public string SchoolclassCodeMonday {get;set;}
public string SchoolclassCodeTuesday {get;set;}
public string SchoolclassCodeWednesday {get;set;}
public string SchoolclassCodeThursday {get;set;}
public string SchoolclassCodeFriday {get;set;}
public string SchoolclassCodeSaturday {get;set;}
public string SchoolclassCodeSunday {get;set;}

The above would work when I would display only the properties as string in a textbox. But what I want is to bind each combox to a mutual ObservableCollection SchoolclassCodes and the SelectedItem aka DisplayMember of the ComboBox must somehow be MAPPED to one of the 7 above Properties AND the SelectedItem if retrieved must supply a row of all 7 schoolclass selected in the combobox.

Or what I actually want just in other words ;-)

Display in the ComboBox the SchoolclassCodes list, set the Value of SelectedItem.SchoolclassCode"WeekdayName" to the Value of the selected ComboboxItem.SchoolclassCode

Well there are some ideas I have but all lack some experience to make them fully working.

I could add to the TimeTableViewModel for each Property a ObservableCollection SchoolclassCodes but that seems very redundant to me. Why should I hold 7 lists for ONE row when each cell has the same list with the same items in it ?

Any suggestions concerning the ViewModels structure and the binding in Wpf are welcome :)

UPDATE: My SchoolclassCodes list is dynamically created, so I there is no possibility about static binding or hardcode string items in XAML...

UPDATE2:

OK I tried to make it working with MVVM:

I had to change the ObservableCollection ClassCodes to ObservableCollection SchoolclassCodes as the Schoolclass object has a reference to Pupil class with strings thats not possible.

Schoolclass.cs:

public string SchoolclassCode {get;set;}
...

TimeTableWeekViewModel.cs:

public ObservableCollection<Schoolclass> SchoolclassCodes
    {
        get { return _schoolclassCodes; }
        set
        {
            _schoolclassCodes = value;
            this.RaisePropertyChanged("SchoolclassCodes");
        }
    }

XAML:

How must the binding look like NOW because the SchoolclassCodes is not found by wpf ?

Answer 1

Since the columns must be auto generated, putting this code in the appropriate place (Loaded event?) should do what you want :

        ObservableCollection<String> Collection = GetCollection();

        foreach (DataGridComboBoxColumn column in DataGrid1.Columns.OfType<DataGridComboBoxColumn>())
        {
            column.ItemsSource = Collection;
        }

Of course, some modifications must be applied!

Answer 2

I recommend that you look into the MVVM (Model-View-ViewModel) pattern if you are doing anything remotely complicated. Also, it is useful to implement INotifyPropertyChanged in your model/viewmodel (e.g. the MyWeek class in my example below). That will notify any other bindings whenever one of your SchoolclassCode<Day> properties is changed.

Here is some simple sample code to get you started:

using System.Collections.ObjectModel;
using System.Linq;

namespace BindingSample
{
    public partial class Window1
    {
        public Window1()
        {
            InitializeComponent();
            SchoolclassCodes = new ObservableCollection<string>(
                Enumerable.Range(1, 10).Select(i => "Code #" + i));
            MyWeeks = new ObservableCollection<MyWeek>(
                Enumerable.Range(1, 5).Select(i => new MyWeek() {SchoolclassCodeMonday = SchoolclassCodes.First()}));
            DataContext = this;
        }

        public ObservableCollection<string> SchoolclassCodes { get; private set; }
        public ObservableCollection<MyWeek> MyWeeks { get; private set; }
    }

    public class MyWeek
    {
        public string SchoolclassCodeMonday { get; set; }
        public string SchoolclassCodeTuesday { get; set; }
        public string SchoolclassCodeWednesday { get; set; }
        public string SchoolclassCodeThursday { get; set; }
        public string SchoolclassCodeFriday { get; set; }
        public string SchoolclassCodeSaturday { get; set; }
        public string SchoolclassCodeSunday { get; set; }
    }
}

---

<Window x:Class="BindingSample.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <Window.Resources>
        <CollectionViewSource x:Key="ClassCodes" Source="{Binding SchoolclassCodes}" />
    </Window.Resources>
    <ListView ItemsSource="{Binding MyWeeks}">
        <ListView.View>
            <GridView>
                <GridView.Columns>
                    <GridViewColumn Header="Monday">
                        <GridViewColumn.CellTemplate>
                            <DataTemplate>
                                <ComboBox SelectedValue="{Binding SchoolclassCodeMonday}"
                                          ItemsSource="{Binding Source={StaticResource ClassCodes}}"
                                          IsSynchronizedWithCurrentItem="False" />
                            </DataTemplate>
                        </GridViewColumn.CellTemplate>
                    </GridViewColumn>
                    <!-- Other columns here... -->
                </GridView.Columns>
            </GridView>
        </ListView.View>
    </ListView>
</Window>

Answer 3

You don't need to mess around with the DataGrid, and you certainly don't need to create any class with seven different properties that you have to implement property-change notification for. The Grid control makes calendars easy.

Your view model should have three classes: Month, Week, and Day. The Week class contains a list of Day objects, and the Month class has a list of Week objects. Each class should have a reference to its parent, i.e. Week in Day and Month in Week.

The Week class's constructor should initialize its Days property to be a list of 7 Day objects. The Month class's constructor has to have more specific logic in it for setting up its Weeks property; I'll leave that to you.

The Day object should expose these properties:

public DayOfWeek DayNumber { get; private set; }
public ObservableCollection<SchoolclassCode> Codes { get { return Week.Codes; } }

as well as a read/write string Code property that does property-change notification.

The Week object should expose:

public ObservableCollection<SchoolclassCode> Codes { get { return Month.Codes; } }
public IEnumerable<Day> Days { get; private set; }
public IEnumerable<string> Codes
{
   get { return Days.Select(x => x.Code); }
}

You can then define a data template for presenting days:

<DataTemplate DataType="{x:Type local:Day}">
   <Grid>
      <Grid.ColumnDefinitions>
         <ColumnDefinition SharedSizeGroup="Sunday"/>
         <ColumnDefinition SharedSizeGroup="Monday"/>
         <ColumnDefinition SharedSizeGroup="Tuesday"/>
         <ColumnDefinition SharedSizeGroup="Wednesday"/>
         <ColumnDefinition SharedSizeGroup="Thursday"/>
         <ColumnDefinition SharedSizeGroup="Friday"/>
         <ColumnDefinition SharedSizeGroup="Saturday"/>
      </Grid.ColumnDefinitions>
      <ComboBox 
         Grid.Column="{Binding DayNumber}" 
         ItemsSource="{Binding Codes}" 
         SelectedValue="{Binding Code, Mode=TwoWay}"/>
   </Grid>
</DataTemplate>

and weeks:

<DataTemplate DataType="{x:Type Week}">
  <ItemsControl ItemsSource="{Binding Days}">
    <ItemsControl.ItemTemplate>
      <ItemsPanelTemplate>
        <StackPanel Orientation="Horizontal"/>
      </ItemsPanelTemplate>
    </ItemsControl.ItemTemplate>
  </ItemsControl>
</DataTemplate>

and months:

<DataTemplate DataType="{x:Type Month}">
  <ItemsControl ItemsSource="{Binding Weeks}" Grid.IsSharedSizeScope="True">
    <ItemsControl.ItemTemplate>
      <ItemsPanelTemplate>
        <StackPanel Orientation="Vertical"/>
      </ItemsPanelTemplate>
    </ItemsControl.ItemTemplate>
  </ItemsControl>
</DataTemplate>

Adding day names and week numbers to the above templates is straightforward.