Validating Data

The following page provides a list of examples that demonstrate how to validate data.

note

All examples in this topic assume that the grid is bound to the Orders table of the Northwind database, unless stated otherwise.

Providing a cell error style

The following example demonstrates how to provide a new style that will change the foreground color of a cell when its value fails the validation process.

<Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid"
     xmlns:local="clr-namespace:Xceed.Wpf.Documentation">
  <Grid.Resources>
     <xcdg:DataGridCollectionViewSource x:Key="cvs_composers"
                                        Source="{Binding Source={x:Static Application.Current}, 
                                                         Path=Composers}"/>
     <Style x:Key="cell_error" TargetType="{x:Type xcdg:DataCell}">
          <Setter Property="Foreground" Value="Red"/>
       </Style>
  </Grid.Resources> 
  <xcdg:DataGridControl ItemsSource="{Binding Source={StaticResource cvs_composers}}"
                                            CellErrorStyle="{StaticResource cell_error}">
     <xcdg:DataGridControl.Columns>
       <xcdg:Column FieldName="Period"
                    CellEditor="{StaticResource periodEditor}">                                   
          <xcdg:Column.CellValidationRules>
             <local:PeriodVSCompositionCountCellValidationRule/>
          </xcdg:Column.CellValidationRules>
       </xcdg:Column>
       <xcdg:Column FieldName="CompositionCount">
          <xcdg:Column.CellValidationRules>
             <local:PeriodVSCompositionCountCellValidationRule />
          </xcdg:Column.CellValidationRules>
       </xcdg:Column>
     </xcdg:DataGridControl.Columns>
  </xcdg:DataGridControl>
</Grid>

Providing binding-level validation

The following example demonstrates how to create a custom ValidationRule and apply it to a column's binding to provide binding-level validation.

The implementation for the YearValidationRule is provided below.

XAML
C#
VB.NET

  <Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid"
      xmlns:local="clr-namespace:Xceed.Wpf.Documentation">
    <Grid.Resources>
      <xcdg:DataGridCollectionViewSource x:Key="cvs_composers"
                                          Source="{Binding Source={x:Static Application.Current}, 
                                                          Path=Composers}"/>
    </Grid.Resources>
  
    <xcdg:DataGridControl ItemsSource="{Binding Source={StaticResource cvs_composers}}"
                          UpdateSourceTrigger="RowEndingEdit">
      <xcdg:DataGridControl.Columns> 
        <xcdg:Column FieldName="BirthYear">
            <xcdg:Column.DisplayMemberBindingInfo>
              <xcdg:DataGridBindingInfo Path="BirthYear">
                  <xcdg:DataGridBindingInfo.ValidationRules>
                    <local:YearValidationRule />
                  </xcdg:DataGridBindingInfo.ValidationRules>
              </xcdg:DataGridBindingInfo>
            </xcdg:Column.DisplayMemberBindingInfo>
        </xcdg:Column>
        <xcdg:Column FieldName="DeathYear">
            <xcdg:Column.DisplayMemberBindingInfo>
              <xcdg:DataGridBindingInfo Path="DeathYear">
                  <xcdg:DataGridBindingInfo.ValidationRules>
                    <local:YearValidationRule />
                  </xcdg:DataGridBindingInfo.ValidationRules>
              </xcdg:DataGridBindingInfo>
            </xcdg:Column.DisplayMemberBindingInfo>
        </xcdg:Column>      
      </xcdg:DataGridControl.Columns>
    </xcdg:DataGridControl>
  </Grid>

using System;
using System.Windows.Controls;
using System.Globalization;
namespace Xceed.Wpf.Documentation
{
  public class YearValidationRule : ValidationRule
  {
    public override ValidationResult Validate( object value, CultureInfo cultureInfo )
    {
      int year = ( int )value;
      if( year > DateTime.Now.Year )
        return new ValidationResult( false, "Chosen year cannot be greater than this year." );
      return ValidationResult.ValidResult;
    }
  }
}

  Imports System
  Imports System.Windows.Controls
  Imports System.Globalization
  Namespace Xceed.Wpf.Documentation
    Public Class YearValidationRule
                Inherits ValidationRule
      Public Overrides Function Validate( ByVal value As Object, _
                                          ByVal cultureInfo As CultureInfo ) As ValidationResult
        Dim year As Integer = CInt( value )
        If year > DateTime.Now.Year Then
          Return New ValidationResult( False, "Chosen year cannot be greater than this year." )
        End If
        Return ValidationResult.ValidResult
      End Function
    End Class
  End Namespace

Providing UI-level validation

The following example demonstrates how to create a custom CellValidationRule and add it to a column's CellValidationRules collection to provide UI-level validation.

The implementation for the PeriodVSCompositionCountCellValidationRule and Person class are provided below.

XAML
C#
VB.NET

<Grid xmlns:xcdg="http://schemas.xceed.com/wpf/xaml/datagrid"
    xmlns:local="clr-namespace:Xceed.Wpf.Documentation">
  <Grid.Resources>
    <xcdg:DataGridCollectionViewSource x:Key="cvs_composers"
                                        Source="{Binding Source={x:Static Application.Current},
                                                        Path=Composers}"/>
    <!--A data provider to bind to the Period enum-->
    <ObjectDataProvider x:Key="periods"
                        MethodName="GetValues"
                        ObjectType="{x:Type local:Period}">
        <ObjectDataProvider.MethodParameters>
          <x:Type TypeName="local:Period"/>
        </ObjectDataProvider.MethodParameters>
    </ObjectDataProvider>
    <!--A cell editor that will be used to edit a Period column with a combo box-->
    <xcdg:CellEditor x:Key="periodEditor">
        <xcdg:CellEditor.EditTemplate>
          <DataTemplate>
              <ComboBox BorderThickness="0"
                        MinHeight="22"
                        VerticalContentAlignment="Top"
                        SelectedValuePath="."
                        ItemsSource="{Binding Source={StaticResource periods}}"
                        SelectedValue="{xcdg:CellEditorBinding}">
                <ComboBox.Resources>
                    <Style TargetType="Popup">
                      <Setter Property="TextElement.Foreground"
                              Value="{DynamicResource {x:Static SystemColors.WindowTextBrushKey}}" />
                    </Style>
                </ComboBox.Resources>
              </ComboBox>
          </DataTemplate>
        </xcdg:CellEditor.EditTemplate>
    </xcdg:CellEditor>
  </Grid.Resources>
  <xcdg:DataGridControl ItemsSource="{Binding Source={StaticResource cvs_composers}}"
                        UpdateSourceTrigger="RowEndingEdit">
    <xcdg:DataGridControl.Columns>
      <xcdg:Column FieldName="Period"
                    CellEditor="{StaticResource periodEditor}">                                   
          <xcdg:Column.CellValidationRules>
            <local:PeriodVSCompositionCountCellValidationRule/>
          </xcdg:Column.CellValidationRules>
      </xcdg:Column>
      <xcdg:Column FieldName="CompositionCount">
          <xcdg:Column.CellValidationRules>
            <local:PeriodVSCompositionCountCellValidationRule />
          </xcdg:Column.CellValidationRules>
      </xcdg:Column>
    </xcdg:DataGridControl.Columns>
  </xcdg:DataGridControl>
</Grid>

  using System;
  using Xceed.Wpf.DataGrid.ValidationRules;
  using Xceed.Wpf.DataGrid;
  using System.Globalization;
  using System.Windows.Controls;
  namespace Xceed.Wpf.Documentation
  { 
  public class PeriodVSCompositionCountCellValidationRule : CellValidationRule
  {
    public override ValidationResult Validate( object value, CultureInfo culture,
                                                CellValidationContext context )
    {
      Row parentRow = context.Cell.ParentRow;
      int compositionCount;
      Period period;
      if( context.Cell.FieldName == "Period" )
      {
        period = ( Period )value;       
        compositionCount = ( int )parentRow.Cells[ "CompositionCount" ].Content;
      }
      else
      {
        period = ( Period )parentRow.Cells[ "Period" ].Content;
        compositionCount = ( int )value;
      }
      if( ( period == Period.Modern ) && compositionCount > 40 )
        return new ValidationResult( false, "Composition count must be less than 50 when the period is set to Modern." );
      return ValidationResult.ValidResult;
    }
  }
  }

  Imports System
  Imports Xceed.Wpf.DataGrid.ValidationRules
  Imports Xceed.Wpf.DataGrid
  Imports System.Globalization
  Imports System.Windows.Controls
  Namespace Xceed.Wpf.Documentation
    Public Class PeriodVSCompositionCountCellValidationRule
                Inherits CellValidationRule
      Public Overrides Function Validate( ByVal value As Object, ByVal culture As CultureInfo, _
                                          ByVal context As CellValidationContext ) As ValidationResult
        Dim parentRow As Row = context.Cell.ParentRow
        Dim compositionCount As Integer
        Dim period As Period
        If context.Cell.FieldName = "Period" Then
          period = CType( value, Period )
          compositionCount = CInt( parentRow.Cells( "CompositionCount" ).Content )
        Else
          period = CType( parentRow.Cells( "Period" ).Content, Period )
          compositionCount = CInt( value )
        End If
        If( ( period = Period.Modern ) And ( compositionCount > 40 ) ) Then
          Return New ValidationResult( False, "Composition count must be less than 50 when the period is set to Modern." );
        End If
        Return ValidationResult.ValidResult
      End Function
    End Class
  End Namespace

Implementation of the Person class

C#
VB.NET

  using System.ComponentModel;
  using System.Windows.Media;
  namespace Xceed.Wpf.Documentation
  {
    public class Person: INotifyPropertyChanged, IDataErrorInfo
    {
      public Person( int personID, string firstName, string lastName, int age )
      {
        m_personID = personID;
        m_firstName = firstName;
        m_lastName = lastName;
        m_age = age;
      }
      public Person()
      {
      }
      public int PersonID
      {
        get
        {
          return m_personID;
        }
      }
      public string FirstName
      {
        get
        {
          return m_firstName;
        }
        set
        {
          if( m_firstName != value )
          {
            m_firstName = value;
            this.OnPropertyChanged( "FirstName" );
          }
        }
      }
      public string LastName
      {
        get
        {
          return m_lastName;
        }
        set
        {
          if( m_lastName != value )
          {
            m_lastName = value;
            this.OnPropertyChanged( "LastName" );
          }
        }
      }
      public int Age
      {
        get
        {
          return m_age;
        }
        set
        {
          if( m_age == value )
            return;
          m_age = value;
          this.OnPropertyChanged( "Age" );
        }
      }
      // INotifyPropertyChanged implementation
      public event PropertyChangedEventHandler PropertyChanged;
      private void OnPropertyChanged( string propertyName )
      {
        if( this.PropertyChanged != null )
          this.PropertyChanged( this, new PropertyChangedEventArgs( propertyName ) );
      }
      // IDataErrorInfo implementation
      [EditorBrowsable( EditorBrowsableState.Never ) ]
      [Browsable( false )]
      public string Error
      {
        get
        {
          return "IDataErrorInfo Error Message";
        }
      }
      [EditorBrowsable( EditorBrowsableState.Never )]
      [Browsable( false )]
      public string this[ string propertyName ]
      {
        get
        {
          if( propertyName == "Age" )
          {
            if( m_age < 18 )
              return "An employee must be 18 years or older.";
          }
          return string.Empty;
        }
      }   
      private string m_firstName = string.Empty;
      private string m_lastName = string.Empty;
      private int m_personID;
      private int m_age = 18;
    }
  }

  Imports System.ComponentModel
  Imports System.Windows.Media
  Namespace Xceed.Wpf.Documentation
    Public Class Person
                Implements INotifyPropertyChanged
      Public Sub New( personID As Integer, firstName As String, lastName As String, age As Integer )
        m_personID = personID
        m_firstName = firstName
        m_lastName = lastName
        m_age = age
      End Sub
      public Sub New()
      End sub   
      Public ReadOnly Property PersonID As Integer
        Get
          Return m_personID
        End Get
      End Property
      Public Property FirstName As String
        Get
          Return m_firstName
        End Get
        Set( ByVal value As String )
          If m_firstName <> value Then
            m_firstName = value
            Me.OnPropertyChanged( "FirstName" )
          End If
        End Set
      End Property
      Public Property LastName As String
        Get
          Return m_lastName
        End Get
        Set( ByVal value As String )
          If m_lastName <> value Then
            m_lastName = value
            Me.OnPropertyChanged( "LastName" )
          End If
        End Set
      End Property
      Public Property Age As Integer
        Get
          Return m_age
        End Get
        Set( ByVal value As Integer )
          If m_age = value Then
            Return
          End If
          m_age = value
          Me.OnPropertyChanged( "Age" )
        End Set
      End Property
      ' INotifyPropertyChanged implementation
      Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
      Private Sub OnPropertyChanged( ByVal propertyName As String )
        If Not Me.PropertyChanged Is Nothing Then
          Me.PropertyChanged( Me, New PropertyChangedEventArgs( propertyName ) )
        End If
      End Sub
      private string m_firstName = string.Empty;
      private string m_lastName = string.Empty;
      private m_personID As Integer
      Private m_age As Integer = 18
    End Class
  End Namespace

Providing a cell error style​

Providing binding-level validation​

Providing UI-level validation​

Providing a cell error style

Providing binding-level validation

Providing UI-level validation