目前,Xamarin.Forms
不支持为按钮提供模板支持,因此没有默认模板可供参考(就像我们在WPF中做的那样),也没有Button
中的ControlTemplate
属性。它只会在目标平台上呈现该平台版本的按钮。
通常支持控件的Content
属性的控件会支持控件模板。一个很好的例子是ContentView
。您可以编写一个自定义按钮控件,同时扩展ContentView
,并提供模板支持,使用ContentPresenter
来呈现相关的按钮。
编辑1 - 具有模板支持的自定义按钮控件
例如:
public class TemplatedButton : ContentView
{
public TemplatedButton()
{
var button = new Button();
button.SetBinding(Button.TextColorProperty, new Binding(nameof(TextColor), source: this));
button.SetBinding(BackgroundColorProperty, new Binding(nameof(BackgroundColor), source: this));
button.SetBinding(IsEnabledProperty, new Binding(nameof(IsEnabled), source: this));
button.SetBinding(Button.TextProperty, new Binding(nameof(Text), source: this));
button.SetBinding(Button.CommandProperty, new Binding(nameof(Command), source: this));
button.SetBinding(Button.CommandParameterProperty, new Binding(nameof(CommandParameter), source: this));
var tapGestureRecognizer = new TapGestureRecognizer();
tapGestureRecognizer.SetBinding(TapGestureRecognizer.CommandProperty, new Binding(nameof(Command), source: this));
tapGestureRecognizer.SetBinding(TapGestureRecognizer.CommandParameterProperty, new Binding(nameof(CommandParameter), source: this));
GestureRecognizers.Add(tapGestureRecognizer);
Content = button;
}
public static readonly BindableProperty TextProperty =
BindableProperty.Create(
"Text", typeof(string), typeof(TemplatedButton),
defaultValue: default(string));
public string Text
{
get { return (string)GetValue(TextProperty); }
set { SetValue(TextProperty, value); }
}
public static readonly BindableProperty CommandProperty =
BindableProperty.Create(
"Command", typeof(ICommand), typeof(TemplatedButton),
defaultValue: new Command((obj) => System.Diagnostics.Debug.WriteLine("TemplatedButton Tapped")));
public ICommand Command
{
get { return (ICommand)GetValue(CommandProperty); }
set { SetValue(CommandProperty, value); }
}
public static readonly BindableProperty CommandParameterProperty =
BindableProperty.Create(
"CommandParameter", typeof(object), typeof(TemplatedButton),
defaultValue: default(object));
public object CommandParameter
{
get { return (object)GetValue(CommandParameterProperty); }
set { SetValue(CommandParameterProperty, value); }
}
public static readonly BindableProperty TextColorProperty =
BindableProperty.Create(
"TextColor", typeof(Color), typeof(TemplatedButton),
defaultValue: default(Color));
public Color TextColor
{
get { return (Color)GetValue(TextColorProperty); }
set { SetValue(TextColorProperty, value); }
}
}
使用示例:
<ResourceDictionary>
<ControlTemplate x:Key="ThreeBorderBtn">
<Grid RowSpacing="0" ColumnSpacing="0" Margin="0">
<BoxView Margin="5" BackgroundColor="Purple" />
<BoxView Margin="10" BackgroundColor="Green" />
<BoxView Margin="15" BackgroundColor="Red" />
<ContentPresenter Margin="20" />
</Grid>
</ControlTemplate>
</ResourceDictionary>
<local:TemplatedButton
HeightRequest="100"
Text="Button Caption!"
TextColor="Teal"
Command="{Binding ClickCommand}"
BackgroundColor="White"
ControlTemplate="{StaticResource ThreeBorderBtn}" />