Xamarin.Forms Multi Triggers


MultiTrigger is not needed frequently but there are some situations where it is very handy. MultiTrigger behaves similarly to Trigger or DataTrigger but it has multiple conditions. All the conditions must be true for a Setters to fire. Here is a simple example:

<!-- Text field needs to be initialized in order for the trigger to work at start -->
<Entry x:Name="email" Placeholder="Email" Text="" />
<Entry x:Name="phone" Placeholder="Phone" Text="" />
<Button Text="Submit">
        <MultiTrigger TargetType="Button">
                <BindingCondition Binding="{Binding Source={x:Reference email}, Path=Text.Length}" Value="0" />
                <BindingCondition Binding="{Binding Source={x:Reference phone}, Path=Text.Length}" Value="0" />
            <Setter Property="IsEnabled" Value="False" />

The example has two different entries, phone and email, and one of them is required to be filled. The MultiTrigger disables the submit button when both fields are empty.