Is it possible to trigger an event using xml code

Question

Is it possible to trigger an event using xml code? Example when button is clicked to focus an Entry?

Answer 1

Hello,​

Welcome to our Microsoft Q&A platform!

I wonder if it is possible to achieve this only using xml code.

No, it's available. Because it lacks related events or properties of the Button and Entry.

Best Regards,

Jarvan Zhang

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Answer 2

To achieve tis function, we need to create a custom control. For example, add a bool property to the cusotm Button and Entry. Then change the appearance of the two views based on the property changes using Triggers.

Here is the sample code, you could refer to it.

public class CustomButton : Button
{
    public bool IsClicked
    {
        set => SetValue(IsClickedProperty, value);
        get => (bool)GetValue(IsClickedProperty);
    }
    public static readonly BindableProperty IsClickedProperty = BindableProperty.Create(nameof(IsClicked), typeof(bool), typeof(CustomButton), null);

    public CustomButton()
    {
        this.Clicked += CustomButton_Clicked;
    }

    private void CustomButton_Clicked(object sender, EventArgs e)
    {
        IsClicked = true;
    }
}

public class CustomEntry : Entry
{
    public bool _IsFocused //because Entry already has IsFocused property, but the property only provides the get method
    {
        set => SetValue(_IsFocusedProperty, value);
        get => (bool)GetValue(_IsFocusedProperty);
    }
    public static readonly BindableProperty _IsFocusedProperty = BindableProperty.Create(nameof(_IsFocused), typeof(bool), typeof(CustomEntry), propertyChanged: ValueChanged);

    public CustomEntry()
    {
        this.Unfocused += CustomEntry_Unfocused;
    }

    private void CustomEntry_Unfocused(object sender, FocusEventArgs e)
    {
        _IsFocused = false;
    }

    private static void ValueChanged(BindableObject bindable, object oldValue, object newValue)
    {
        var customEntry = bindable as CustomEntry;
        if ((bool)newValue)
        {
            customEntry.Focus();
        }
    }
}

page.xaml

<local:CustomButton x:Name="customButton">
    <local:CustomButton.Triggers>
        <DataTrigger TargetType="local:CustomButton" Binding="{Binding Source={x:Reference customEntry},Path=_IsFocused}" Value="False">
            <Setter Property="IsClicked" Value="False"/>
        </DataTrigger>
    </local:CustomButton.Triggers>
</local:CustomButton>
<local:CustomEntry x:Name="customEntry">
    <local:CustomEntry.Triggers>
        <DataTrigger TargetType="local:CustomEntry" Binding="{Binding Source={x:Reference customButton},Path=IsClicked}" Value="True">
            <Setter Property="_IsFocused" Value="True"/>
        </DataTrigger>
    </local:CustomEntry.Triggers>
</local:CustomEntry>