Passing parameters to a template

问题

Say I have defined a button with rounded corners.

<Style x:Key="RoundButton" TargetType="Button">
    <!-- bla bla -->
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="Button">
                <Border CornerRadius="0,5,5,0" />
                <!-- bla bla -->
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

I it possible that the user of this button can specify the CornerRadius? Can I use a TemplateBinding? But where should I bind to? (to Tag?)

回答1:

In order to use a TemplateBinding, there must be a property on the templated control (Button, in this case). Button does not have a CornerRadius or equivalent property, so your options are:

hard code the value in the template
Hijack another property (such as Tag) to store this information. This is quicker, but lacks type safety, is harder to maintain, and prevents other uses of that property.
Subclass Button and add the propery you need, then provide a template for that subclass. This takes a little longer but yields a much nicer experience for consumers of your control.

回答2:

In addition to Kent's suggestions, you could also create an attached property to define the CornerRadius on the button, and bind to that property in the template

回答3:

The button type doesn't have a property for CornerRadius, so templating this won't be possible. I think the easiest way is creating a new class which inherits from Button and add a new dependency property for the CornerRadius. Like this:

using System.Windows;
using System.Windows.Controls;

namespace WpfApplication3
{
    public class RoundedButton:Button
    {
        public CornerRadius CornerRadius
        {
            get { return (CornerRadius) GetValue(CornerRadiusProperty); }
            set { SetValue(CornerRadiusProperty, value); }
        }
        public static readonly DependencyProperty CornerRadiusProperty =
            DependencyProperty.Register("CornerRadius", typeof (CornerRadius), 
            typeof (RoundedButton), new UIPropertyMetadata());
    }
}

In xaml you can use it like:

<Local:RoundedButton 
    Style="{DynamicResource RoundButton}" 
    Width="64" Height="32" 
    Content="Hello" 
    CornerRadius="1,5,10,5" 
    Background="#FF9CFFD5" />

A template binding to the CornerRadius will work without a problem now.

来源：https://stackoverflow.com/questions/1031196/passing-parameters-to-a-template

标签

.net

wpf

xaml

controltemplate