WPF DataGrid: Displaying 2 decimal places when not editing, but full number when editing

Question

im am trying to have a datagrid, where when the user enters the value and presses enter, it displays the data with 2 decimal points of precision.

However when they click in to edit it, i want them to be able to view the whole number again.

What i currently have is:

<DataGridTextColumn Header="s" Binding="{Binding s, StringFormat=N2}" ElementStyle="{StaticResource TextColumnWhite}" >
    <DataGridTextColumn.EditingElementStyle>
        <Style TargetType="{x:Type TextBox}">
            <Setter Property="Text" Value="{Binding s}" />
            <Setter Property="Background" Value="Red" />
        </Style>
    </DataGridTextColumn.EditingElementStyle>
</DataGridTextColumn>

The red background is displaying for the datagrid cell but the number inside is not updating to the non formatted value.

Thanks for any help

Answer 1

You need to take away the string format at the parent level (which is overriding the EditingElementStyle) - and instead set the string format for the binding expression only in the styles for EditingElementStyle - but also for the regular ElementStyle (non-editing mode) which is a TextBlock style:

<DataGridTextColumn Header="s" ElementStyle="{StaticResource TextColumnWhite}">

    <!-- editing view -->
    <DataGridTextColumn.EditingElementStyle>
        <Style TargetType="{x:Type TextBox}">
            <Setter Property="Text" Value="{Binding s}" />                            
            <Setter Property="Background" Value="Red" />
        </Style>                        
    </DataGridTextColumn.EditingElementStyle>

    <!-- not editing view -->
    <DataGridTextColumn.ElementStyle>
        <Style TargetType="{x:Type TextBlock}">
            <Setter Property="Text" Value="{Binding s, StringFormat=N2}" />
            <Setter Property="Background" Value="Transparent" />
        </Style>
    </DataGridTextColumn.ElementStyle>

</DataGridTextColumn>