wpf datagrid generate rows according to a selected value

Question

Model:

Enumerations:

public enum StabilityLevel
{
    Unstable,
    Neutral,
    Stable
}

public enum WindspeedClass
{
    Class1,
    Class2,
    Class3
}

Windrose:

public class Windrose
{
        // percentual value for given direction
        private short[][][] _percentage;

        // average wind speed in wind speed classes        
        private float[][] _average;

        public Windrose()
        {            
            _percentage = new short[Enum.GetNames(typeof(StabilityLevel)).Length][][];
            foreach (StabilityLevel stability in EnumUtil.GetValues<StabilityLevel>())
            {
                _percentage[(int) stability] = new short[Enum.GetNames(typeof(WindspeedClass)).Length][];
                foreach (WindspeedClass windspeed in EnumUtil.GetValues<WindspeedClass>())
                {
                    // We reserve 0 for a special no-wind value, and we limit the maximum number of directions to 36 
                    _percentage[(int) stability][(int) windspeed] = new short[37]; 
                }
            }

            _average = new float[Enum.GetNames(typeof(StabilityLevel)).Length][];
            foreach (StabilityLevel stability in EnumUtil.GetValues<StabilityLevel>())
            {
                _average[(int) stability] = new float[Enum.GetNames(typeof(WindspeedClass)).Length];
            }    

            NumberOfDirections = 8;        
        }

        public string Name { get; set; }
        public int NumberOfDirections { get; set; }
        public StabilityLevel StabilityLevel { get; set; }
        public WindspeedClass Windspeed { get; set; }

        public short[] Percentage
        {
            get
            {
                return _percentage[(int) StabilityLevel][(int) Windspeed];
            }            
        }
        public float Average
        {
            get
            {
                return _average[(int) StabilityLevel][(int) Windspeed];
            }
            set
            {
                _average[(int)StabilityLevel][(int)Windspeed] = value;
            }
        }                                  
}

View:

Now let's look at this view (xaml) that is used as a modal window for creating a new windrose:

  <Grid>
    <Grid.RowDefinitions>
      <RowDefinition Height="Auto"/>
      <RowDefinition Height="Auto"/>
      <RowDefinition Height="Auto"/>
      <RowDefinition Height="Auto"/>
      <RowDefinition Height="Auto"/>
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
      <ColumnDefinition Width="*"/>
      <ColumnDefinition Width="*"/>
    </Grid.ColumnDefinitions>                

  <Label Grid.Row="0" HorizontalAlignment="Left" ContentStringFormat="{}{0}:" Content="Name" />
  <TextBox Grid.Row="0" Grid.Column="1" VerticalAlignment="Center" Text="{Binding Path=Name, UpdateSourceTrigger=PropertyChanged}" />

  <Label Grid.Row="1" HorizontalAlignment="Left" ContentStringFormat="{}{0}:" Content="Number of directions" />
  <ComboBox Grid.Row="1" Grid.Column="1" VerticalAlignment="Center" SelectedItem="{Binding Path=NumberOfDirections, UpdateSourceTrigger=PropertyChanged}">
    <ComboBoxItem Content="4" />
    <ComboBoxItem Content="8" />
    <ComboBoxItem Content="12" />
    <ComboBoxItem Content="16" />
    <ComboBoxItem Content="36" />   
  </ComboBox>

  <Label Grid.Row="2" HorizontalAlignment="Left" ContentStringFormat="{}{0}:" Content="Stability Level" />
  <StackPanel Grid.Row="2" Grid.Column="1" Orientation="Vertical">
    <RadioButton HorizontalAlignment="Left" IsChecked="{Binding Path=StabilityLevel, Converter={StaticResource EnumToBoolConverter}, ConverterParameter={x:Static model:StabilityLevel.Unstable}}" Content="A - Unstable" />
    <RadioButton HorizontalAlignment="Left" IsChecked="{Binding Path=StabilityLevel, Converter={StaticResource EnumToBoolConverter}, ConverterParameter={x:Static model:StabilityLevel.Neutral}}" Content="B - Neutral" />
    <RadioButton HorizontalAlignment="Left" IsChecked="{Binding Path=StabilityLevel, Converter={StaticResource EnumToBoolConverter}, ConverterParameter={x:Static model:StabilityLevel.Stable}}" Content="C - Stable" />
  </StackPanel>

  <Grid Grid.Row="3" Grid.ColumnSpan="2">                    
    <Grid.RowDefinitions>
      <RowDefinition Height="Auto" />
      <RowDefinition Height="Auto" />
      <RowDefinition Height="Auto" />
    </Grid.RowDefinitions>

    <Grid.ColumnDefinitions>
      <ColumnDefinition />
      <ColumnDefinition />
    </Grid.ColumnDefinitions>

    <RadioButton Grid.Row="0" HorizontalAlignment="Left" IsChecked="{Binding Path=Windspeed, Converter={StaticResource EnumToBoolConverter}, ConverterParameter={x:Static model:WindspeedClass.Class1}}" Content="1 - 0 to 2 meters per second"  />
    <TextBox Grid.Row="0" Grid.Column="1" Width="30" Text="{Binding Path=???, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Center" />

    <RadioButton Grid.Row="1" HorizontalAlignment="Left" IsChecked="{Binding Path=Windspeed, Converter={StaticResource EnumToBoolConverter}, ConverterParameter={x:Static model:WindspeedClass.Class2}}" Content="2 - 2 to 4 meters per second" />
    <TextBox Grid.Row="1" Grid.Column="1" Width="30" Text="{Binding Path=???, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Center" />

    <RadioButton Grid.Row="2" HorizontalAlignment="Left" IsChecked="{Binding Path=Windspeed, Converter={StaticResource EnumToBoolConverter}, ConverterParameter={x:Static model:WindspeedClass.Class3}}" Content="3 - over 4 meters per second" />
    <TextBox Grid.Row="2" Grid.Column="1" Width="30" Text="{Binding Path=???, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Center" />
  </Grid>

  <DataGrid Grid.Row="4" Margin="5" ItemsSource="{Binding Percentage}"  AutoGenerateColumns="False">
    <DataGrid.Columns>
      <DataGridTextColumn Header="Wind direction" Width="SizeToHeader">
      </DataGridTextColumn>

      <DataGridTemplateColumn Header="Percentage" Width="SizeToHeader">
        <DataGridTemplateColumn.CellTemplate>
          <DataTemplate>
            <TextBox Text="{Binding ???}"/>
          </DataTemplate>
        </DataGridTemplateColumn.CellTemplate>
      </DataGridTemplateColumn>
    </DataGrid.Columns>
  </DataGrid>  

 </Grid>

So for each 'stability level' <-> 'windspeed class' pair, the windrose instance keeps an array of 37 values and an extra float value.

I don't know how to do 2 things:

A)

I don't know how to create this table (DataGrid). I want to be able to change the number of rows that are generated dynamically according to the selected NumberOfDirections. The selected NumberOfDirections also determine the "step"(360 degrees is divided by NumberOfDirections) between two subsequent rows.

B)

In grid with x:Name="WSClass" I would like to be able to bind items of _average array to the TextBoxes so that each TextBox that corresponds to a certain RadioButton(that represents a wind speed class) has value _average[selected stability][windspeed of the corresponding RadioButton].

Answer 1

EDIT (22.11.2013):
I have asked a related question about the bare mechanics of how this could be achieved. User Sheridan has answered it there. As I cannot ask him to rewrite his solution to my problem in the context of this question (windroses) I decided the only way to have this answered properly is to answer my own question.

Warning: Long post

Model classes:

public enum StabilityLevel
{
    Unstable,
    Neutral,
    Stable
}

public enum WindspeedClass
{
    Class1,
    Class2,
    Class3
}

public class Windrose
{
  #region Fields
  // percentual value for given direction
  private short[][][] _percentage;        
  // average wind speed in wind speed class for given stability level        
  private float[][] _average;
  #endregion


  public Windrose()  {    ... initialization ...  }

  #region Properties

  public string Name { get; set; }
  public int NumberOfDirections { get; set; }
  public StabilityLevel StabilityLevel { get; set; }
  public WindspeedClass Windspeed { get; set; }

  // indexer  
  public short this[StabilityLevel stability, WindspeedClass windspeedClass, int direction]
  {
      get
      {                
          return _percentage[(int) stability][(int) windspeedClass][direction];
      }
      set
      {
          _percentage[(int)stability][(int)windspeedClass][direction] = value;
      }
  }  

  #endregion    

}

View Model classes:

WindroseWindDirection:

As Sheridan suggested I created a data type class to hold all information that I need to display in a datagrid row.

Therefore

• it implements INotifyPropertyChanged interface
• implements a property for each column that I want to display in the datagrid

public class WindroseWindDirection : INotifyPropertyChanged
{
    private string _direction;
    private short _directionValue;

    #region Construction

    public WindroseWindDirection() : this("not available",0) {}

    public WindroseWindDirection(string direction, short defaultDirectionValue)
    {
        _direction = direction;
        _directionValue = defaultDirectionValue;
    }

    #endregion

    #region Properties

    public string Direction
    {
        get
        {
            return _direction;
        }
        set
        {
            if (String.Compare(_direction, value) != 0)
            {
                _direction = value;
                OnPropertyChanged("Direction");
            }

        }
    }
    public short DirectionValue
    {
        get
        {
            return _directionValue;
        }
        set
        {
            if (_directionValue != value)
            {
                OnPropertyChanged("DirectionValue");
                _directionValue = value;
            }                
        }
    }

    #endregion

    #region INotifyPropertyChanged implementation

    public event PropertyChangedEventHandler PropertyChanged;
    protected virtual void OnPropertyChanged(string propertyName)
    {
        PropertyChangedEventHandler handler = this.PropertyChanged;
        if (handler != null) handler(this, new PropertyChangedEventArgs(propertyName));
    }

    #endregion
}

AddModifyWindroseDialogViewModel:

There is an ObservableCollection<int> for the ComboBox in the view and an ObservableCollection<WindroseWindDirection> for each combination of StabilityLevel <-> WindspeedClass . Because a user has to be able to edit all this information at once we create a jagged array for it.

Basically the idea is that based on the value of 2 properties that dictate the stability level and windspeed class we return the appropriate ObservableCollection<WindroseWindDirection> through third property. If the user changes the number of directions for the whole windrose, we'll call a private method UpdateFilteredItems() . Having an ObservableCollection<WindroseWindDirection> actually allows us to bind it to the ItemsSource of the DataGrid and subsequently define the Columns of DataGrid ourselves and have the individual properties of WindroseWindDirection bound to the columns.

// just for reference: MVVM Light base view model class is used
public class AddModifyWindroseDialogViewModel : ViewModelBase
{
    #region Fields

    // holds the actual model class
    private Windrose _wr;
    // holds an ObservableCollection for each combination of StabilityLevel & WindspeedClass
    private ObservableCollection<WindroseWindDirection>[][] _dataGrid;
    // for Combobox
    private ObservableCollection<int> _numberOfDirectionValues = new ObservableCollection<int>(Constants.WindroseAllowedNumberOfDirections);    

    #endregion

        #region Construction

        public AddModifyWindroseDialogViewModel(Windrose windrose)
        {            
            _wr = windrose;            

            // create array[][] of observable collections, one for each stability <-> windspeed pair
            _dataGrid = new ObservableCollection<WindroseWindDirection>[Enum.GetNames(typeof(StabilityLevel)).Length][];
            int step = 360 / NumberOfDirections;
            foreach (StabilityLevel stability ... )
            {
                _dataGrid[(int) stability] = new ObservableCollection<WindroseWindDirection>[Enum.GetNames(typeof(WindspeedClass)).Length];
                foreach (WindspeedClass windspeed ... )
                {
                    _dataGrid[(int)stability][(int)windspeed] = new ObservableCollection<WindroseWindDirection>();
                    // Add 'No wind' special first row
                    _dataGrid[(int)stability][(int)windspeed].Add(new WindroseWindDirection("No wind", _wr[stability, windspeed, 0]));
                    // Add the rest
                    for (int i = 0; i < NumberOfDirections; i++)
                    {
                        _dataGrid[(int)stability][(int)windspeed].Add(new WindroseWindDirection(String.Format("{0} degrees", i * step), _wr[stability, windspeed, i + 1]));
                    }
                }
            }
        }

        #endregion

        #region Properties

        public String Name
        {
            get
            {
                return _wr.Name;
            }
            set
            {
                if (String.Equals(_wr.Name, value) == false)
                {
                    _wr.Name = value;
                    RaisePropertyChanged("Name");
                }
            }
        }

        public int NumberOfDirections
        {
            get
            {
                return _wr.NumberOfDirections;
            }
            set
            {
                if (_wr.NumberOfDirections != value)
                {
                    _wr.NumberOfDirections = value;
                    RaisePropertyChanged("NumberOfDirections");
                    UpdateFilteredItems();
                }
            }
        }        
        public ObservableCollection<int> NumberOfDirectionsValues
        {
            get
            {
                return _numberOfDirectionValues;
            }
        }
        public StabilityLevel StabilityLevel
        {
            get
            {
                return _wr.StabilityLevel;
            }
            set
            {
                if (Enum.Equals(_wr.StabilityLevel, value) == false)
                {
                    _wr.StabilityLevel = value;
                    RaisePropertyChanged("StabilityLevel");
                    RaisePropertyChanged("FilteredItems");
                    RaisePropertyChanged("WindSpeedAverageClass1");
                    RaisePropertyChanged("WindSpeedAverageClass2");
                    RaisePropertyChanged("WindSpeedAverageClass3");                                        
                }
            }
        }
        public WindspeedClass Windspeed
        {
            get
            {
                return _wr.Windspeed;
            }
            set
            {
                if (Enum.Equals(_wr.Windspeed, value) == false)
                {
                    _wr.Windspeed = value;
                    RaisePropertyChanged("Windspeed");
                    RaisePropertyChanged("FilteredItems");
                }
            }
        }
        public ObservableCollection<WindroseWindDirection> FilteredItems
        {
            get
            {
                return _dataGrid[(int) StabilityLevel][(int) Windspeed];
            }
        }
        public float WindSpeedAverageClass1
        {
            get
            {
                return _wr[StabilityLevel, WindspeedClass.Class1];
            }
            set
            {
                if (_wr[StabilityLevel, WindspeedClass.Class1] != value)
                {
                    _wr[StabilityLevel, WindspeedClass.Class1] = value;
                    RaisePropertyChanged("WindSpeedAverageClass1");
                }
            }
        }        
        public float WindSpeedAverageClass2
        {
            get
            {
                return _wr[StabilityLevel, WindspeedClass.Class2];
            }
            set
            {
                if (_wr[StabilityLevel, WindspeedClass.Class2] != value)
                {
                    _wr[StabilityLevel, WindspeedClass.Class2] = value;
                    RaisePropertyChanged("WindSpeedAverageClass2");
                }
            }
        }
        public float WindSpeedAverageClass3
        {
            get
            {
                return _wr[StabilityLevel, WindspeedClass.Class3];
            }
            set
            {
                if (_wr[StabilityLevel, WindspeedClass.Class3] != value)
                {
                    _wr[StabilityLevel, WindspeedClass.Class3] = value;
                    RaisePropertyChanged("WindSpeedAverageClass3");
                }
            }
        }        

        #endregion

        private void UpdateFilteredItems()
        {
            /**/
            int step = 360 / NumberOfDirections;
            foreach (StabilityLevel stability ... )
            {                
                foreach (WindspeedClass windspeed ... )
                {
                    // Clear the old values
                    _dataGrid[(int)stability][(int)windspeed].Clear();                    
                    // Add 'No wind' special value
                    _dataGrid[(int)stability][(int)windspeed].Add(new WindroseWindDirection("No wind", _wr[stability, windspeed, 0]));
                    // Add degrees
                    for (int i = 0; i < NumberOfDirections; i++)
                    {
                        _dataGrid[(int)stability][(int)windspeed].Add(new WindroseWindDirection(String.Format("{0} degrees", i * step), _wr[stability, windspeed, i + 1]));
                    }
                }
            }
            RaisePropertyChanged("FilteredItems");
        }                                            

}

View :

<Grid>
  <Grid.RowDefinitions>
    <RowDefinition Height="Auto"/>
    <RowDefinition Height="Auto"/>
    <RowDefinition Height="Auto"/>
    <RowDefinition Height="Auto"/>
    <RowDefinition Height="Auto"/>
  </Grid.RowDefinitions>
  <Grid.ColumnDefinitions>
    <ColumnDefinition Width="*"/>
    <ColumnDefinition Width="*"/>
  </Grid.ColumnDefinitions>                

<Label Grid.Row="0" HorizontalAlignment="Left" ContentStringFormat="{}{0}:" Content="Name" />
<TextBox Grid.Row="0" Grid.Column="1" VerticalAlignment="Center" Text="{Binding Path=Name, UpdateSourceTrigger=PropertyChanged}" />

<Label Grid.Row="1" HorizontalAlignment="Left" ContentStringFormat="{}{0}:" Content="Number of directions" />
<ComboBox Grid.Row="1" Grid.Column="1" VerticalAlignment="Center" SelectedItem="{Binding Path=NumberOfDirections, UpdateSourceTrigger=PropertyChanged}">
  <ComboBoxItem Content="4" />
  <ComboBoxItem Content="8" />
  <ComboBoxItem Content="12" />
  <ComboBoxItem Content="16" />
  <ComboBoxItem Content="36" />   
</ComboBox>

<Label Grid.Row="2" HorizontalAlignment="Left" ContentStringFormat="{}{0}:" Content="Stability Level" />
<StackPanel Grid.Row="2" Grid.Column="1" Orientation="Vertical">
  <RadioButton HorizontalAlignment="Left" IsChecked="{Binding Path=StabilityLevel, Converter={StaticResource EnumToBoolConverter}, ConverterParameter={x:Static model:StabilityLevel.Unstable}}" Content="A - Unstable" />
  <RadioButton HorizontalAlignment="Left" IsChecked="{Binding Path=StabilityLevel, Converter={StaticResource EnumToBoolConverter}, ConverterParameter={x:Static model:StabilityLevel.Neutral}}" Content="B - Neutral" />
  <RadioButton HorizontalAlignment="Left" IsChecked="{Binding Path=StabilityLevel, Converter={StaticResource EnumToBoolConverter}, ConverterParameter={x:Static model:StabilityLevel.Stable}}" Content="C - Stable" />
</StackPanel>

<Grid Grid.Row="3" Grid.ColumnSpan="2">                    
  <Grid.RowDefinitions>
    <RowDefinition Height="Auto" />
    <RowDefinition Height="Auto" />
    <RowDefinition Height="Auto" />
  </Grid.RowDefinitions>

  <Grid.ColumnDefinitions>
    <ColumnDefinition />
    <ColumnDefinition />
  </Grid.ColumnDefinitions>


  <TextBox Grid.Row="1" Grid.Column="1" Width="30" Text="{Binding Path=WindSpeedAverageClass2, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Center" />

  <RadioButton Grid.Row="0" HorizontalAlignment="Left" IsChecked="{Binding Path=Windspeed, Converter={StaticResource EnumToBoolConverter}, ConverterParameter={x:Static model:WindspeedClass.Class1}}" Content="1 - 0 to 2 meters per second"  />
  <TextBox Grid.Row="0" Grid.Column="1" Width="30" Text="{Binding Path=WindSpeedAverageClass1, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Center" />

  <RadioButton Grid.Row="1" HorizontalAlignment="Left" IsChecked="{Binding Path=Windspeed, Converter={StaticResource EnumToBoolConverter}, ConverterParameter={x:Static model:WindspeedClass.Class2}}" Content="2 - 2 to 4 meters per second" />
  <TextBox Grid.Row="1" Grid.Column="1" Width="30" Text="{Binding Path=WindSpeedAverageClass2, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Center" />

  <RadioButton Grid.Row="2" HorizontalAlignment="Left" IsChecked="{Binding Path=Windspeed, Converter={StaticResource EnumToBoolConverter}, ConverterParameter={x:Static model:WindspeedClass.Class3}}" Content="3 - over 4 meters per second" />
  <TextBox Grid.Row="2" Grid.Column="1" Width="30" Text="{Binding Path=WindSpeedAverageClass3, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Center" />
</Grid>

<!-- Here is the DataGrid. Please notice how ObservableCollection<WindroseWindDirection> is bound to the DataGrid ItemsSource and how individual columns are bound with properties of WindroseWindDirection  -->
<DataGrid Grid.Row="4" Margin="5" ItemsSource="{Binding FilteredItems}"  AutoGenerateColumns="False">
  <DataGrid.Columns>        
      <DataGridTextColumn Header="Wind Direction" Width="SizeToHeader" Binding="{Binding Direction}">
      </DataGridTextColumn>                          
      <DataGridTemplateColumn Header="Percent" Width="SizeToHeader">
          <DataGridTemplateColumn.CellTemplate>
              <DataTemplate>
                  <TextBox Text="{Binding DirectionValue, UpdateSourceTrigger=PropertyChanged}"/>
              </DataTemplate>                                
          </DataGridTemplateColumn.CellTemplate>
      </DataGridTemplateColumn>
  </DataGrid.Columns>
</DataGrid>  

</Grid>