I would like to show 'additional details' Textbox when the previous TextBox
's value is not 0.00 (zero). This is easily accomplished with DataTriggers:
<TextBox Name="FirstTB" Text="{Binding Amount, StringFormat=F2}"/><!--when this TB is not 0-->
<TextBox Name="SecondTB"> <!--show this TB-->
<TextBox.Style>
<Style TargetType="{x:Type TextBox}">
<Style.Triggers>
<DataTrigger Binding="{Binding Amount}" Value="0">
<Setter Property="Visibility" Value="Hidden"/>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBox.Style>
</TextBox>
<TextBox Name="ThirdTB"/>
The issue is, however, when changing value of FirstTB
to <> 0 and pressing Tab
the focus jumps to the ThirdTB instead of SecondTB (even though SecondTB
now is Visible due to the DataTrigger). How can I fix this issue?
Sadly, UpdateSourceTrigger=PropertyChanged
does not appear to be an option due to its interference with StringFormat
s - it gives terrible UX when you are editing the value, carret jumps around like crazy due to constant StringFormat evaluation. Viewmodel used in example above:
public class MyVM : INotifyPropertyChanged
{
public event PropertyChangedEventHandler PropertyChanged;
private double _amount;
public double Amount
{
get { return _amount; }
set
{
_amount = value;
PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Amount)));
}
}
}
Maybe a stupid work around. But this will do the work:
View:
<TextBox Name="SecondTB" IsVisibleChanged="SecondTB_OnIsVisibleChanged">
<!--show this TB-->
<TextBox.Style>
<Style TargetType="{x:Type TextBox}">
<Style.Triggers>
<DataTrigger Binding="{Binding Amount, Mode=OneWay}" Value="0">
<Setter Property="Visibility" Value="Collapsed"/>
</DataTrigger>
</Style.Triggers>
</Style>
</TextBox.Style>
</TextBox>
C#:
private void SecondTB_OnIsVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
{
if (((bool) e.NewValue))
{
if(!(sender is TextBox txbx)) return;
ThirdTB.GotFocus += ThirdTbOnGotFocus;
}
}
private void ThirdTbOnGotFocus(object sender, RoutedEventArgs e)
{
SecondTB.Focus();
ThirdTB.GotFocus -= ThirdTbOnGotFocus;
}