是否可以重新加载UserControl的XAML属性？

Question

I have some frameworkElements inside XAML, and I define some properties like background, and cursor.

In code behind, I change these properties, and when an event triggers, I want to reload these initial properties defined in XAML. Is this possible or I need to redifine manually in code behind?

Thanks.

Answer 1

A control defined in XAML is essentially defining an instance . Once you have the instance , the object is just like every other object you deal with. Having access to the instance defined in XAML within your code behind is akin to creating a new object in the code behind and then adjusting its properties at run time.

When you want the property value to change; you don't revert your property changes, you simply change them to what you desire.

Answer 2

I would suggest looking into DataTriggers for making temporary changes based on some value. This will change the value of a property while a specific condition is true, and revert it to its original value when the condition is false.

For example, here's a style that will change the cursor to a Wait cursor while loading, and change the background to Red if it is invalid.

<Style TargetType="{x:Type local:MyUserControl}">
    <Setter Property="Cursor" Value="Arrow" />
    <Setter Property="Background" Value="White" />

    <Style.Triggers>
        <DataTrigger Binding="{Binding IsLoading}" Value="True">
            <Setter Property="Cursor" Value="Wait" />
        </DataTrigger>
        <DataTrigger Binding="{Binding IsValid}" Value="True">
            <Setter Property="Background" Value="Red" />
        </DataTrigger>
    </Style.Triggers>
</Style>

Of course, you'll have to define the IsLoading and IsValid properties behind your UserControl, and set them to true/false at the appropriate times in your code-behind.