【问题标题】:wpf custom button best approachwpf自定义按钮最佳方法
【发布时间】:2012-10-27 19:38:03
【问题描述】:

我想在 WPF 中创建一个自定义 Button。当然,该按钮将是一个 UserControl,它将包含许多视觉元素(如描边、高光、阴影、发光、图像等)。

问题是,如果我使用 DependencyProperties 并在 XAML 中绑定它们,我将无法在 DesignTime 看到结果(我尝试实现 IsInDesignMode 方法,但由于某种原因,我无法理解我的 VS当我在 UserControls 上使用此方法时会崩溃,否则它工作得很好),这绝对不好。

所以我正在考虑根本不使用 XAML,并在后面的代码中完成我的所有工作。

你们怎么看?

【问题讨论】:

  • 我认为你应该使用 Expression Blend。
  • 另外,与其扩展UserControl,不如考虑为Button控件编写自己的ControlTemplate
  • 我只是一个新手,我只想学习。顺便说一句,我从未使用过 Expression Blend,所以我不确定该怎么想。另外,我希望这个按钮是高度可定制的,所以我想标准的 WPF 编辑器将是我的选择。 @狒狒
  • 正如 dbaseman 建议的那样,ControlTemplate 就是为此目的而设计的。它可以由任意数量的嵌套元素组成,因此您当然可以通过自定义 UserControl 完成任何您想做的事情,但不会出现这种方法带来的一些数据绑定故障。
  • 正确的做法是使用Expression Blend修改基本Button的ControlTemplate。就是这样。

标签: wpf button user-controls


【解决方案1】:

和您一样,当我刚开始并想了解如何/如何使用模板以及使用模板时,我需要进行大量的试验和错误。希望我的研究和一些循序渐进的组件可以帮助您根据自己的喜好进行定制并了解事物的来源。

首先,在尝试了解新的“模板样式”如何工作时,我为我的 Any Manipulating Styles 创建了一个简单的独立 WPF 应用程序(“AMS”)。这样一来,我就不必永远等待,看看在我的其他主要项目和主题的试验/错误过程中会是什么样子。

由此,我创建了一个名为“TestingStyles”的新 WPF 窗口。保存/编译,运行,没问题。

现在,在 TestingStyles 窗口的“查看代码”中,我已经为自定义类添加了我正在使用的任何内容...为了帮助逐步显示,我创建了以下内容:

namespace AMS
{
    /// <summary>
    /// Interaction logic for TestingStyles.xaml
    /// </summary>
    public partial class TestingStyles : Window
    {
        public TestingStyles()
        {
            InitializeComponent();
        }
    }

    // Enumerator for a custom property sample...
    public enum HowToShowStatus
    {
        ShowNothing,
        ShowImage1
    }


    public class YourCustomButtonClass : Button
    {
        public YourCustomButtonClass()
        {
            // auto-register any "click" will call our own custom "click" handler
            // which will change the status...  This could also be done to simplify
            // by only changing visibility, but shows how you could apply via other
            // custom properties too.
            Click += MyCustomClick;
        }

        protected void MyCustomClick(object sender, RoutedEventArgs e)
        {
            if( this.ShowStatus == HowToShowStatus.ShowImage1 )
                this.ShowStatus = HowToShowStatus.ShowNothing;
            else
                this.ShowStatus = HowToShowStatus.ShowImage1;
        }


        public static readonly DependencyProperty ShowStatusProperty =
              DependencyProperty.Register("ShowStatus", typeof(HowToShowStatus),
              typeof(YourCustomButtonClass), new UIPropertyMetadata(HowToShowStatus.ShowNothing));

        public HowToShowStatus ShowStatus
        {
            get { return (HowToShowStatus)GetValue(ShowStatusProperty); }
            set { SetValue(ShowStatusProperty, value); }
        }
    }

}

如您所见,自定义“按钮”类位于默认测试样式之外的底部:窗口声明......所以它都在同一个“项目”中。

在这个 XAML 示例中,我引用了一个“TaskComplete.png”图形文件(它应该仅用于示例目的,直接添加到项目中......即使是用于示例目的的简单笑脸)。 因此,创建这样一个简单的 .png 文件……甚至使用 Microsoft Paint 并用眼睛和微笑画一个圆圈。在根目录下保存到项目中(稍后进入路径内容,先让它工作)。

保存并重新编译项目,以便在您开始定义 XAML 模板时项目公开知道新的“类”(按钮)是什么。

现在,回到 TestingStyles 设计器并将其放入分屏中,这样您就可以同时看到设计器和 XAML 标记...并且只需替换为以下内容...

<Window x:Class="AMS.TestingStyles"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:my="clr-namespace:AMS"
        Title="TestingStyles" Height="300" Width="300" >

    <Window.Resources>
        <!-- Build a "Style" based on an anticpated target control type of YourCustomButtonClass.
            per the "my:" reference, the "my" is an "alias" to the xmlsn:my in the declaration above,
            so the XAML knows which library to find such control.  In this case, I've included within
            the actual forms's 'View Code' as a class at the bottom.  

            As soon as you assign an "x:Key" reference, its like its telling XAML to make this a PRIVATE
            style so you don't reference it explicitly (yet)
        -->
        <Style TargetType="my:YourCustomButtonClass" x:Key="keyYourCustomButtonClass">
            <!-- put whatever normal "settings" you want for your common look / feel, color -->
            <Setter Property="BorderThickness" Value="1"/>
            <Setter Property="HorizontalContentAlignment" Value="Center"/>
            <Setter Property="VerticalContentAlignment" Value="Center"/>
            <Setter Property="Padding" Value="0,0,1,1"/>
            <Setter Property="Width" Value="100" />
            <Setter Property="Height" Value="30" />

            <!-- Now, for the template of the button.  Things can get really crazy here
              as you are now defining what you want the "button" to look like, borders, 
              content, etc. In this case, I have two borders to give the raise/sunken effect 
              of a button and it has its own colors -->
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="Button" >
                        <!-- The x:Name references used during triggers to know what it is "applying" changes to -->
                        <Border x:Name="BorderTopLeft"
                                BorderBrush="Gainsboro" 
                                BorderThickness="0,0,1.5,1.5">

                            <Border x:Name="BorderBottomRight"
                                BorderBrush="Gray" 
                                BorderThickness="1.5,1.5,0,0">
                                <!-- Now, what control  type do you want the button to have... 
                                    Ex: You could use a grid (as I have here), stack panels, etc -->
                                <Grid Background="LightBlue" >
                                    <!-- I'm defining as two columns wide, one row tall.  
                                        First column fixed width 20 pixels example for an image -->
                                    <Grid.ColumnDefinitions>
                                        <ColumnDefinition Width="20px" />
                                        <ColumnDefinition Width="*" />
                                    </Grid.ColumnDefinitions>
                                    <Grid.RowDefinitions>
                                        <RowDefinition />
                                    </Grid.RowDefinitions>

                                    <!-- Now, create the controls I want available within my "template".
                                        when assigned with "x:Name", thats like a property withing the template
                                        that triggers can associate and update to. -->
                                    <Image x:Name="btnImage" 
                                        Grid.Row="0" Grid.Column="0"
                                        Stretch="None"
                                        VerticalAlignment="Stretch" HorizontalAlignment="Stretch" 
                                        Source="TaskComplete.png"
                                        Visibility="Visible" />

                                    <!-- and also have the text for the button to show the user -->
                                    <TextBlock x:Name="txtNewBtn" 
                                        Grid.Row="0" Grid.Column="1"
                                        Padding="5"
                                        HorizontalAlignment="Left"
                                        VerticalAlignment="Center"
                                    Text="{TemplateBinding Content}" />
                                    <!-- The "{TemplateBinding Content}" means to set the text based on 
                                        the "CONTENT" property of the original button and not use a fixed value -->
                                </Grid>
                            </Border>
                        </Border>
                        <!-- Now, some triggers for the button itself... some can be property based, others data-based -->
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsPressed" Value="true">
                                <!-- What properties do we want to change when user CLICKS
                                    on the button, give the "EFFECT" of click down/up by
                                    changing the "Margin" and border thicknesses...  -->
                                <Setter Property="Margin" Value="1,1,0,0"/>
                                <!-- Notice the "TargetName" below referring to the x:Name I've applied in template above 
                                    so when the user clicks on the button, it changes the border thickness properties of
                                    each to give the effect of a normal button clicking.  I'm widening one border, shrinking other -->
                                <Setter TargetName="BorderTopLeft" Property="BorderThickness" Value="2.5,2.5,0,0"/>
                                <Setter TargetName="BorderBottomRight" Property="BorderThickness" Value="0,0,.5,.5"/>
                            </Trigger>

                            <!-- Here, I have a custome property on the class for "ShowStatus".  The binding is to itself
                                regardless of how many instances of this type of "button" are on a given form 
                                First trigger happens when the value is changed to "ShowNothing", but can also change 
                                when set to "ShowImage1" or other as you may need applicable
                            -->
                            <DataTrigger Binding="{Binding Path=ShowStatus, RelativeSource={RelativeSource Self}}" Value="ShowNothing">
                                <Setter TargetName="btnImage" Property="Visibility" Value="Hidden"/>
                            </DataTrigger>
                            <DataTrigger Binding="{Binding Path=ShowStatus, RelativeSource={RelativeSource Self}}" Value="ShowImage1">
                                <Setter TargetName="btnImage" Property="Visibility" Value="Visible"/>
                            </DataTrigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>

        <!-- NOW, we can expose any instance of "YourCustomButtonClass" button to use the style based on definition above 
            any instance of such YourCustomButtonClass will automatically reflect this style / look -->
        <Style TargetType="my:YourCustomButtonClass" BasedOn="{StaticResource keyYourCustomButtonClass}" />

    </Window.Resources>

    <Grid>
        <my:YourCustomButtonClass Content="Button" VerticalAlignment="Top" ShowStatus="ShowImage1" />
    </Grid>
</Window>

这应该为您定义自己的模板以及元素如何开始绑定在一起提供了一个很好的起点。运行此示例后,当您更改模板的任何颜色、边距、填充等时,您将立即看到该组件对控件的视觉影响。

玩得开心,不要用头撞墙……

顺便说一句,一旦这个工作正常,那么你可以在

中获取样式元素的东西
<Window.Resources>
</Window.Resources> 

并将其放入 Windows 资源字典中,使其对您的项目具有全局性,而不仅仅是此测试表单。

【讨论】:

  • 非常感谢。代码很干净,我想我可以很好地理解它。现在我正在尝试实现它......手指交叉:)
  • 缺少BasedOn 的第二种样式 - 搜索我的错误数小时...:D
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