Question

I have created a registration form in silverlight 4, where i have a large number of text-boxes, in front of each text box i have placed a text-block as a required field validator, when any of the textbox left empty while loosing focus, the textblock placed in front of it must become red.

textboxes named textbox1, textbox2 … and so as the textblocks

the problem is, i do not want code the specific method for each specific textbox, all i want to do is to complete such in just two three methods

here i did some coding which doesn’t seems to be correct

    private void textBox_LostFocus(object sender, RoutedEventArgs e)
    {
        var textBox = (TextBox) sender;
        if (textbox.Text == "")
           { 
               var textblock = "textblock" +  textBox.Name.Remove(0,7);
               TextblockColorChange(textblock);
           }
    }
    private void TextblockColorChange(object sender)
    {
         var textblock = (TextBlock) sender;
         textblock.Foreground= new SolidColorBrush(Colors.Red);
    }

please suggest some better way to do so..

Answer 1

you need something like this,

XAML part:

<Grid x:Name="LayoutRoot" Background="White">
    <StackPanel Orientation="Horizontal" Height="25">
        <TextBox Width="150" LostFocus="TextBox_LostFocus"/>
        <TextBlock Text="*" Foreground="#FF0000" VerticalAlignment="Center" Margin="10,0,0,0" Visibility="Collapsed"/>
    </StackPanel>
</Grid>

C# Part:

        private void TextBox_LostFocus(object sender, RoutedEventArgs e)
    {
        var textbox = sender as TextBox;
        if(textbox == null) return;

        var stackPanel = textbox.Parent as StackPanel;
        if(stackPanel == null) return;

        var textBlock = stackPanel.Children.Where(a => a is TextBlock).FirstOrDefault();
        if (textBlock == null) return;
        if (string.IsNullOrEmpty(textbox.Text)) textBlock.Visibility = Visibility.Visible;
        else textBlock.Visibility = Visibility.Collapsed;
    }