How to get a total colum from two input column in DataGrid

Question

hi guys. how to calculate the two input columns values to Total column. plz help me..

<DataGrid x:Name="dgArrearPost" HorizontalAlignment="Left" Background="White" AutoGenerateColumns="False" IsReadOnly="False" CanUserAddRows="False" Margin="283,317,0,0" VerticalAlignment="Top" Height="288" Width="563" KeyDown="dgArrearPost_KeyDown" KeyUp="dgArrearPost_KeyUp" CellEditEnding="dgArrearPost_CellEditEnding" SelectedCellsChanged="dgArrearPost_SelectedCellsChanged">

<DataGrid.ColumnHeaderStyle>

<Style TargetType="{x:Type DataGridColumnHeader}">

<Setter Property="FontWeight" Value="Bold" />

<Setter Property="HorizontalContentAlignment" Value="Center"/>

</Style>

</DataGrid.ColumnHeaderStyle>

<DataGrid.Effect>

<DropShadowEffect/>

</DataGrid.Effect>

<DataGrid.Columns>

<DataGridTextColumn Header="Subject1" FontWeight="Bold" Width="100" Binding="{Binding Subject1,ValidatesOnExceptions=True,StringFormat=d }" />

<DataGridTextColumn Header="Subject2" FontWeight="Bold" Width="100" Binding="{Binding Subject2,ValidatesOnExceptions=True,StringFormat=d}" IsReadOnly="False" />

<DataGridTextColumn Header="Subject3" FontWeight="Bold" Width="100" Binding="{Binding Subject3,ValidatesOnExceptions=True,StringFormat=d }" IsReadOnly="False" />

<DataGridTextColumn Header="Total" FontWeight="Bold" Width="100" Binding="{Binding Total,ValidatesOnExceptions=True,StringFormat=d }" IsReadOnly="False" />

</DataGrid.Columns>

</DataGrid>

 

 

private void dgSubject_CellEditEnding(object sender, DataGridCellEditEndingEventArgs e)

{

if (e.EditAction == DataGridEditAction.Commit)

{

var column = e.Column as DataGridBoundColumn;

if (column != null)

{

var bindingPath = (column.Binding as Binding).Path.Path;

else if (bindingPath == "Subject1")

{

var el = e.EditingElement as TextBox;

if (el!=null)

{

// How to Calculate the Subject1,Subject2,Subject3 Columns 

}

}

}

}

}