StandardDeviationFunction Class
See Also  Members   Example 
Xceed.Wpf.DataGrid Assembly > Xceed.Wpf.DataGrid.Stats Namespace : StandardDeviationFunction Class

Class that represents the Standard Deviation statistical function, which is the measure of the degree of dispersion of sample or population data from the mean value. This feature is available only in the Professional Edition

Object Model


Syntax

Visual Basic (Declaration) 
Public Class StandardDeviationFunction 
   Inherits StatFunction
C# 
public class StandardDeviationFunction : StatFunction

Example

All examples in this topic assume that the grid is bound to the Orders or Employees tables of the Northwind database, unless stated otherwise.
The following example demonstrates how to display the results of various statistical functions in and outside of a grid.
XAMLCopy Code
<Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid"> 
  <Grid.Resources> 
    <xcdg:DataGridCollectionViewSource x:Key="cvs_orderdetails" 
                                       Source="{Binding Source={x:Static Application.Current}, 
                                                        Path=OrderDetails}"> 
     <xcdg:DataGridCollectionViewSource.StatFunctions> 
       <xcdg:CountFunction ResultPropertyName="orderid_count" 
                           SourcePropertyName="OrderID"/> 
       <xcdg:SumFunction ResultPropertyName="unitprice_sum" 
                         SourcePropertyName="UnitPrice"/> 
       <xcdg:AverageFunction ResultPropertyName="unitprice_average" 
                             SourcePropertyName="UnitPrice"/> 
       <xcdg:SumFunction ResultPropertyName="quantity_sum" SourcePropertyName="Quantity"/> 
     </xcdg:DataGridCollectionViewSource.StatFunctions> 
     <xcdg:DataGridCollectionViewSource.GroupDescriptions> 
       <xcdg:DataGridGroupDescription PropertyName="ProductID"/>       
 </xcdg:DataGridCollectionViewSource.GroupDescriptions> 
    </xcdg:DataGridCollectionViewSource> 
   <xcdg:StatResultConverter x:Key="valueConverter"/> 
  </Grid.Resources> 
  <DockPanel> 
    <StackPanel Orientation="Horizontal" DockPanel.Dock="Top"> 
      <TextBlock Text="Total Orders: "/> 
      <TextBlock Text="{Binding ElementName=OrderDetailsGrid, 
                 Path=StatContext.orderid_count}"/> 
    </StackPanel> 
     <StackPanel Orientation="Horizontal" DockPanel.Dock="Top"> 
       <TextBlock Text="Average Unit Price: "/> 
     <TextBlock Text="{Binding ElementName=OrderDetailsGrid, 
                        Path=StatContext.unitprice_average, 
                        Converter={StaticResource valueConverter}, 
                        ConverterParameter=f2}"/> 
    </StackPanel> 
    <xcdg:DataGridControl x:Name="OrderDetailsGrid" 
                          ItemsSource="{Binding Source={StaticResource cvs_orderdetails}}" 
                          DockPanel.Dock="Bottom"> 
      <xcdg:DataGridControl.DefaultGroupConfiguration> 
        <xcdg:GroupConfiguration>  
        <xcdg:GroupConfiguration.Footers> 
           <DataTemplate> 
               <xcdg:StatRow> 
               <xcdg:StatCell FieldName="UnitPrice" 
                                   ResultPropertyName="unitprice_sum"/> 
               <xcdg:StatCell FieldName="Quantity" ResultPropertyName="quantity_sum"/> 
               <xcdg:StatCell FieldName="OrderID" ResultPropertyName="orderid_count"/> 
               <xcdg:StatCell FieldName="UnitPrice" 
                              ResultPropertyName="unitprice_average" 
                              ResultConverterParameter="f2"/> 
             </xcdg:StatRow> 
           </DataTemplate> 
         </xcdg:GroupConfiguration.Footers> 
        </xcdg:GroupConfiguration> 
      </xcdg:DataGridControl.DefaultGroupConfiguration>     
    </xcdg:DataGridControl> 
  </DockPanel> 
</Grid>
The following example demonstrates how to change the statistical context of a TextBlock that displays the results of a statistical function when the current item is changed. The statistical context of the TextBlock will be changed in the grid's PropertyChanged event handler by using the GetParentGroupFromItem method to retrieve the current group and set it as the new statistical context. To simplify the code below, the DataContext of the StackPanel could have been modified rather than the DataContext of each TextBlock. The implementation of the PropertyChanged event handler is located below.
XAMLCopy Code
<Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid"> 
  <Grid.Resources> 
    <xcdg:DataGridCollectionViewSource x:Key="cvs_orderdetails" 
                                    Source="{Binding Source={x:Static Application.Current},  
                                                     Path=OrderDetails}"> 
 
      <xcdg:DataGridCollectionViewSource.StatFunctions> 
        <xcdg:CountFunction ResultPropertyName="orderid_count" 
                            SourcePropertyName="OrderID"/> 
        <xcdg:AverageFunction ResultPropertyName="unitprice_average" 
                              SourcePropertyName="UnitPrice"/>               
      </xcdg:DataGridCollectionViewSource.StatFunctions> 
      <xcdg:DataGridCollectionViewSource.GroupDescriptions> 
        <xcdg:DataGridGroupDescription PropertyName="ProductID"/> 
      </xcdg:DataGridCollectionViewSource.GroupDescriptions> 
    </xcdg:DataGridCollectionViewSource> 
    <xcdg:StatResultConverter x:Key="valueConverter"/> 
  </Grid.Resources> 
  <DockPanel> 
    <StackPanel Orientation="Horizontal" DockPanel.Dock="Top"> 
      <TextBlock Text="Results for product "/> 
      <TextBlock x:Name="CurrentGroupTitle" Text="{Binding Name}"/> 
      <TextBlock Text=": "/> 
      <TextBlock Text="     Total Orders-"/> 
      <TextBlock x:Name="TotalOrders" Text="{Binding orderid_count}"/> 
      <TextBlock Text="     Average Unit Price-"/> 
      <TextBlock x:Name="AveragePrice" 
                 Text="{Binding unitprice_average, 
                        Converter={StaticResource valueConverter}, 
                        ConverterParameter=f2}"/> 
    </StackPanel> 
    <xcdg:DataGridControl x:Name="OrderDetailsGrid" 
                          ItemsSource="{Binding Source={StaticResource cvs_orderdetails}}" 
                          PropertyChanged="CurrentItemChanged" 
                          DockPanel.Dock="Bottom"/> 
  </DockPanel> 
</Grid>
The following code provides the implementation of the PropertyChanged event handler.
Visual BasicCopy Code
Private Sub CurrentItemChanged( ByVal sender As Object, _
                                ByVal e AsPropertyChangedEventArgs )
  If e.PropertyName = "CurrentItem" Then

    If Me.OrderDetailsGrid.CurrentItem Is Nothing Then
      Return

    Dim group As CollectionViewGroup =
              Me.OrderDetailsGrid.GetParentGroupFromItem( Me.OrderDetailsGrid.CurrentItem )

    Me.CurrentGroupTitle.DataContext = group
    Me.TotalOrders.DataContext = group
    Me.AveragePrice.DataContext = group
  End If
End Sub
The following code provides the implementation of the PropertyChanged event handler.
C#Copy Code
private void CurrentItemChanged( object sender, PropertyChangedEventArgs e )
{
 if( e.PropertyName == "CurrentItem" )
 {

   if( this.OrderDetailsGrid.CurrentItem == null )
     return;

   CollectionViewGroup group =
             this.OrderDetailsGrid.GetParentGroupFromItem( this.OrderDetailsGrid.CurrentItem );

   this.CurrentGroupTitle.DataContext = group;
   this.TotalOrders.DataContext = group;
   this.AveragePrice.DataContext = group;
 }
}
The following example demonstrates how to create a custom data template that will be used in the footers of the first-level groups to display the results of various statistical functions.
XAMLCopy Code
<Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid"> 
  <Grid.Resources> 
    <xcdg:DataGridCollectionViewSource x:Key="cvs_orderdetails" 
                                       Source="{Binding Source={x:Static Application.Current}, 
                                                        Path=OrderDetails}">  
    <xcdg:DataGridCollectionViewSource.StatFunctions> 
       <xcdg:CountFunction ResultPropertyName="orderid_count" 
                           SourcePropertyName="OrderID"/> 
       <xcdg:SumFunction ResultPropertyName="unitprice_sum" 
                         SourcePropertyName="UnitPrice"/> 
       <xcdg:AverageFunction ResultPropertyName="unitprice_average" 
                             SourcePropertyName="UnitPrice"/> 
       <xcdg:SumFunction ResultPropertyName="quantity_sum" 
                         SourcePropertyName="Quantity"/> 
     </xcdg:DataGridCollectionViewSource.StatFunctions>        
      <xcdg:DataGridCollectionViewSource.GroupDescriptions> 
        <xcdg:DataGridGroupDescription PropertyName="ProductID"/> 
      </xcdg:DataGridCollectionViewSource.GroupDescriptions> 
    </xcdg:DataGridCollectionViewSource> 
   <xcdg:StatResultConverter x:Key="valueConverter"/> 
  </Grid.Resources> 
  <xcdg:DataGridControl x:Name="OrderDetailsGrid" 
                        ItemsSource="{Binding Source={StaticResource cvs_orderdetails}}"> 
    <xcdg:DataGridControl.DefaultGroupConfiguration> 
      <xcdg:GroupConfiguration> 
        <xcdg:GroupConfiguration.Footers> 
          <xcdg:GroupHeaderFooterItemTemplate VisibleWhenCollapsed="True"> 
            <DataTemplate> 
              <Border Background="#999999" 
                      BorderBrush="LightBlue" 
                      BorderThickness="3" 
                      Margin="5" > 
                <Grid> 
                  <Grid.ColumnDefinitions> 
                    <ColumnDefinition/> 
                    <ColumnDefinition/> 
                  </Grid.ColumnDefinitions> 
                  <Grid.RowDefinitions> 
                    <RowDefinition/> 
                    <RowDefinition/> 
                    <RowDefinition/> 
                    <RowDefinition/> 
                  </Grid.RowDefinitions> 
                  <TextBlock Text="Total Orders: " Grid.Row="0" Grid.Column="0"/> 
                   <TextBlock Text="{Binding RelativeSource={RelativeSource Self}, 
                                             Path=(xcdg:DataGridControl.StatContext).orderid_count}" 
                              Grid.Row="0" Grid.Column="1"/>                     
                    <TextBlock Text="Total Quantity Sold: " Grid.Row="1" Grid.Column="0"/> 
                   <TextBlock Text="{Binding RelativeSource={RelativeSource Self}, 
                                   Path=(xcdg:DataGridControl.StatContext).quantity_sum}" 
                                   Grid.Row="1" Grid.Column="1"/>   
                    <TextBlock Text="Total Sales: " Grid.Row="2" Grid.Column="0"/> 
                   <TextBlock Text="{Binding RelativeSource={RelativeSource Self}, 
                                             Path=(xcdg:DataGridControl.StatContext).unitprice_sum}" 
                              Grid.Row="2" Grid.Column="1"/>   
                    <TextBlock Text="Average Unit Price: " Grid.Row="3" Grid.Column="0"/> 
                   <TextBlock Text="{Binding RelativeSource={RelativeSource Self}, 
                                             Path=(xcdg:DataGridControl.StatContext).unitprice_average, 
                                             Converter={StaticResource valueConverter}, 
                                             ConverterParameter=f2}" 
                              Grid.Row="3" Grid.Column="1"/>          
                  </Grid> 
                </Border>  
              </DataTemplate>   
            </xcdg:GroupHeaderFooterItemTemplate> 
          </xcdg:GroupConfiguration.Footers> 
        </xcdg:GroupConfiguration> 
      </xcdg:DataGridControl.DefaultGroupConfiguration> 
      <xcdg:DataGridControl.View> 
        <xcdg:CardView AllowCardResize="True"/> 
      </xcdg:DataGridControl.View> 
    </xcdg:DataGridControl> 
  </Grid>
The following example demonstrates how to explicitly define detail descriptions for the DataRelations found in the DataTable to which the grid is bound and how to calculate statistical functions for a detail description whose results will be displayed in the StatRows contained in the footer sections of the details to which the description's corresponding detail configuration will be applied.
XAMLCopy Code
<Grid> 
  <Grid.Resources> 
     <xcdg:DataGridCollectionViewSource x:Key="cvs_employees" 
                                        Source="{Binding Source={x:Static Application.Current},  
                                                         Path=Employees}"> 
 
       <xcdg:DataGridCollectionViewSource.DetailDescriptions> 
          <xcdg:DataRelationDetailDescription RelationName="Employee_Orders" 
                                              Title="Employee Orders"> 
             <xcdg:DataRelationDetailDescription.DetailDescriptions> 
                <xcdg:DataRelationDetailDescription RelationName="Order_OrderDetails" 
                                                    Title="Order Details"> 
                   <xcdg:DataRelationDetailDescription.ItemProperties> 
                      <xcdg:DataGridItemProperty Name="UnitPrice" /> 
                      <xcdg:DataGridItemProperty Name="Quantity" /> 
                      <xcdg:DataGridItemProperty Name="Discount" /> 
                   </xcdg:DataRelationDetailDescription.ItemProperties> 
                   <xcdg:DataRelationDetailDescription.StatFunctions>                           
                      <xcdg:SumFunction ResultPropertyName="sum_quantity" 
                                        SourcePropertyName="Quantity" /> 
                      <xcdg:AverageFunction ResultPropertyName="average_unitprice" 
                                            SourcePropertyName="UnitPrice" /> 
                   </xcdg:DataRelationDetailDescription.StatFunctions> 
                </xcdg:DataRelationDetailDescription> 
             </xcdg:DataRelationDetailDescription.DetailDescriptions> 
          </xcdg:DataRelationDetailDescription> 
       </xcdg:DataGridCollectionViewSource.DetailDescriptions> 
     </xcdg:DataGridCollectionViewSource> 
  </Grid.Resources> 
  
  <xcdg:DataGridControl x:Name="EmployeesGrid" 
                      ItemsSource="{Binding Source={StaticResource cvs_employees}}" 
                      ItemsSourceName="Employee Information" 
                      AutoCreateDetailConfigurations="True"> 
 
    <xcdg:DataGridControl.DetailConfigurations> 
       <xcdg:DetailConfiguration RelationName="Employee_Orders"> 
          <xcdg:DetailConfiguration.DetailConfigurations> 
             <xcdg:DetailConfiguration RelationName="Order_OrderDetails"> 
                <xcdg:DetailConfiguration.Footers> 
                   <DataTemplate> 
                      <xcdg:StatRow Background="AliceBlue"> 
                         <xcdg:StatCell FieldName="UnitPrice" 
                                        ResultPropertyName="average_unitprice" 
                                        ResultConverterParameter="f2" /> 
                         <xcdg:StatCell FieldName="Quantity" 
                                        ResultPropertyName="sum_quantity" />                              
                      </xcdg:StatRow> 
                   </DataTemplate> 
                </xcdg:DetailConfiguration.Footers> 
             </xcdg:DetailConfiguration> 
          </xcdg:DetailConfiguration.DetailConfigurations> 
       </xcdg:DetailConfiguration> 
     </xcdg:DataGridControl.DetailConfigurations>   
   </xcdg:DataGridControl> 
</Grid>

Remarks

Only the statistical functions that are added to the StatFunctions collection of a DataGridCollectionView or DataGridCollectionViewSource can be used.

The values used to calculate the results of a statistical function are retrieved from its statistical context. For example, if an element that displays the results of a statistical function is contained in a group footer, the element's statistical context will be the group, and the results of the statistical function will be calculated according to the values of the data items in the group. If the same element is placed in the footers of a grid, then its statistical context is provided by a grid (through the StatContext property) and all the data items will be used to calculate the results.

The same statistical function can be used by more than one element, regardless of the statistical context. For example, if the average of a column is to be displayed in both the footers of a group and a grid, only one AverageFunction needs to be added to the StatFunctions collection.

Statistical functions that are calculated for a specific detail-level cannot be accessed by parent, child, or sibling detail-levels nor can they be accessed by a master grid and vice-versa.

With the exception of the CountFuntion, a null reference (Nothing in Visual Basic) and DBNull values will be ignored.

Notes

The EntirePopulation property allows the Standard Deviation statistical function to calculate its result on population data rather than sample data.
a null reference (Nothing in Visual Basic) and DBNull values will be ignored.

Inheritance Hierarchy

System.Object
   Xceed.Wpf.DataGrid.Stats.StatFunction
      Xceed.Wpf.DataGrid.Stats.StandardDeviationFunction

Requirements

Supported Operating Systems: Windows Server 2003 Service Pack 1; Windows Vista; Windows XP Service Pack 2

See Also