CODEWITHSUNDEEP
wpf
Lucifer
Lucifer

Reputation: 2357

Which combination of controls can we use for indicating a mandatory field?

I have figured out three different ways to represent a mandatory field label. However I not sure whose use is ideal. One requirement is that the label should support access keys. Please help me understand which of them should be used. Alternative suggestions are also appreciated.

<Label Width="200" HorizontalAlignment="Left" Target="{Binding ElementName=mytb}">
    <TextBlock>
        <Run Text="*" Foreground="Red" FontWeight="Heavy" />
        <AccessText Text="_Name"/>
    </TextBlock>
</Label>

<Label VerticalAlignment="Center" HorizontalAlignment="Center" Target="{Binding ElementName=mytb}">
    <StackPanel Orientation="Horizontal" Grid.Row="17" Grid.Column="0" HorizontalAlignment="Right">
        <TextBlock Text="*" Foreground="Red" VerticalAlignment="Center" FontWeight="Heavy"></TextBlock>
        <AccessText Text="_Name:" />
    </StackPanel>
</Label>

<StackPanel Orientation="Horizontal">
    <TextBlock Text="*" Foreground="Red" VerticalAlignment="Center" FontWeight="Heavy"/>
    <Label Content="_Name" VerticalAlignment="Center" Target="{Binding ElementName=mytb}"/>
</StackPanel>

Upvotes: 2

Views: 1359

Answers (2)

Chevul Ervin
Chevul Ervin

Reputation: 883

"Should be used" is relative. For example we can think in terms of performance. This could mean using a version which would give the smaller visual tree. Normally the Textblock is pretty light on this but lacks the Target property so access keys would not work. From your solutions the third one is better then the second one because it contains directly the StackPanel without the Label wrapped around it. The first solution with the Run text element seems an elegant one and I prefer that. Regarding the functionality you want to achieve I would mark the TextBox itself as mandatory for example with a validation rule on the binding. This way the marking could appear and disappear as the user types. See example : http://www.nbdtech.com/Blog/archive/2010/07/05/wpf-adorners-part-3-ndash-adorners-and-validation.aspx. Also regarding the visual tree and deciding which controls to use I recommend the Snoop tool: http://snoopwpf.codeplex.com.

Upvotes: 0

Sheridan
Sheridan

Reputation: 69985

If I had to choose one of your examples, I would choose the first, but if not, then I would use an Attached Property for this instead:

<TextBox Text="{Binding SomeProperty}" Attached:TextBoxProperties.IsMandatory="True" />

Of course, you would have the small problem of creating an Attached Property, but red asterisks (*) are so last era. My IsMandatory property basically displays a message in the TextBox when it is empty, but this is WPF... yours could add a red asterisk or anything else that you can imagine. You could even use this Attached Property to add an asterisk onto the Label instead of the TextBox like in my example.

My Attached Property works in conjunction with my Label and LabelColour Attached Properties which each add extra functionality... the Label property provides a simple ControlTemplate (which is the default TextBox template with an extra TextBlock) which it reads from the App.xaml page. The LabelColour property just lets me select different Foreground colours for the extra TextBlock, but is internally set to Red when using the IsMandatory property.

My point is this: you could just go with an old red asterisk like so many before you, or you could branch out and utilise the features that WPF provides to come up with a better solution.

Upvotes: 1

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