.NET MAUI DataForm Validation Styling

You can customize the validation look using the following styling properties:

• ValidationSummaryStyle(of type Style with target type DataFormValidationSummaryView)—Defines the style of the validation summary view.
• ValidationSummaryLabelStyle(of type Style with target type Label)—Defines the validation summary label style.
• ValidationSummaryImageStyle(of type Style with target type Image)—Defines the validation summary image style.

Example

The following examples demonstrate how to style the DataForm validation summary.

1. Define the RadDataForm:

• XAML

<telerik:RadDataForm x:Name="dataForm"
                     ValidationSummaryLabelStyle="{StaticResource ValidationLabelStyle}"
                     ValidationSummaryImageSource="away.png"
                     ValidationSummaryStyle="{StaticResource ValidationSummaryStyle}"
                     IsValidationSummaryVisible="True"
                     ValidationMode="LostFocus">
    <telerik:RadDataForm.BindingContext>
        <local:EditorsViewModel />
    </telerik:RadDataForm.BindingContext>
</telerik:RadDataForm>

Note that local in the snippet above points to the namespace where the EditorsViewModel is defined.

2. Define the ValidationSummaryStyle:

• XAML

<Style x:Key="ValidationSummaryStyle" TargetType="telerik:DataFormValidationSummaryView">
    <Setter Property="BackgroundColor" Value="LightGrey" />
    <Setter Property="BorderThickness" Value="2" />
    <Setter Property="BorderColor" Value="Red" />
    <Setter Property="HorizontalOptions" Value="Center" />
</Style>

3. Define the ValidationLabelStyle:

• XAML

<Style x:Key="ValidationLabelStyle" TargetType="Label">
    <Setter Property="TextColor" Value="Red" />
    <Setter Property="VerticalTextAlignment" Value="Center" />
    <Setter Property="HorizontalTextAlignment" Value="Center" />
    <Setter Property="HorizontalOptions" Value="Center" />
</Style>

4. Add the following namespace:

• XAML

xmlns:telerik="http://schemas.telerik.com/2022/xaml/maui"

5. Define the ViewModel used as a BindingContext for the RadDataForm:

• C#

public class EditorsViewModel : NotifyPropertyChangedBase
{
    private string name;
    private DateTime? startDate;
    private DateTime? endDate;
    private double? people;
    private bool? visited;
    private TimeSpan? duration;
    private EnumValue accommodation = EnumValue.Apartment;
    public enum EnumValue
    {
        SingleRoom,
        Apartment,
        House
    }

    [Required]
    [Display(Name = "Select accomodation")]
    public EnumValue Accommodation
    {
        get
        {
            return this.accommodation;
        }
        set
        {
            if (this.accommodation != value)
            {
                this.accommodation = value;
                this.OnPropertyChanged();
            }
        }
    }

    [Required]
    [Display(Name = "First Name")]
    public string FirstName
    {
        get => this.name;
        set => this.UpdateValue(ref this.name, value);
    }

    [Required]
    [Display(Name = "Start date")]
    public DateTime? StartDate
    {
        get => this.startDate;
        set => this.UpdateValue(ref this.startDate, value);
    }

    [Required]
    [Display(Name = "End Date")]
    public DateTime? EndDate
    {
        get => this.endDate;
        set => this.UpdateValue(ref this.endDate, value);
    }

    [Required]
    [Display(Name = "Number of People")]
    [Range(1, 10)]
    public double? People
    {
        get => this.people;
        set => this.UpdateValue(ref this.people, value);
    }

    [Display(Name = "Visited before")]
    public bool? Visited
    {
        get => this.visited;
        set => this.UpdateValue(ref this.visited, value);
    }

    [Display(Name = "Duration")]
    public TimeSpan? Duration
    {
        get => this.duration;
        set => this.UpdateValue(ref this.duration, value);
    }
}

The following image shows what the DataForm control looks like when the styles described above are applied:

For a runnable example with the DataForm Validation Styling scenario, see the SDKBrowser Demo Application and go to DataForm > Styling category.