WPF访问控件模板（ControlTemplate）内部的控件

ControlTemplate 定义的控件一般情况外部是无法访问的，由 ControlTemplate 或 DataTemplate 生成的控件都是“ 由 Template 生成的控件 ”。

ControlTemplate 和 DataTemplate 两个类均派生自 FrameworkTemplate 类，这个类有个名为 FindName 的方法供我们检索其内部控件。也就是说，只要我们能拿到 Template，找到其内部控件就不成问题。对于ControlTemplate对象，访问其目标控件的Template属性就能拿到。

<!--...--> 
　　<Window.Resources>
        <Style x:Key="ButtonStyle" TargetType="{x:Type Button}">
            <Setter Property="Height" Value="100"/>
            <Setter Property="Width" Value="200"/>
            <Setter Property="Background" Value="Transparent"/>
            <Setter Property="BorderBrush" Value="Black"/>
            <Setter Property="Foreground" Value="Black"/>
            <Setter Property="BorderThickness" Value="2"/>
            <Setter Property="Padding" Value="1"/>
            <Setter Property="Template">
                <Setter.Value>
                    <ControlTemplate TargetType="{x:Type Button}">
                        <Border x:Name="border" Background="{TemplateBinding Background}" BorderBrush="{TemplateBinding BorderBrush}"
                                BorderThickness="{TemplateBinding BorderThickness}" CornerRadius="10">
                            <Grid>
                                <Grid.RowDefinitions>
                                    <RowDefinition/>
                                    <RowDefinition/>
                                </Grid.RowDefinitions>
                                <Grid.ColumnDefinitions>
                                    <ColumnDefinition/>
                                    <ColumnDefinition/>
                                </Grid.ColumnDefinitions>
                                <TextBlock x:Name="text1" Text="111" HorizontalAlignment="Center" VerticalAlignment="Center" FontSize="18"/>
                                <TextBlock x:Name="text2" Text="222" HorizontalAlignment="Center" VerticalAlignment="Center" FontSize="18" Grid.Column="1"/>
                                <TextBlock x:Name="text3" Text="333" HorizontalAlignment="Center" VerticalAlignment="Center" FontSize="18" Grid.Row="1"/>
                                <TextBlock x:Name="text4" Text="444" HorizontalAlignment="Center" VerticalAlignment="Center" FontSize="18" Grid.Row="1" Grid.Column="1"/>
                            </Grid>
                        </Border>
                        <ControlTemplate.Triggers>
                            <Trigger Property="IsMouseOver" Value="true">
                                <Setter Property="BorderBrush" TargetName="border" Value="#FF8AABF8"/>
                            </Trigger>
                        </ControlTemplate.Triggers>
                    </ControlTemplate>
                </Setter.Value>
            </Setter>
        </Style>
    </Window.Resources>
    <Grid>
        <Button x:Name="btn" Style="{DynamicResource ButtonStyle}" Click="Button_Click"/>
    </Grid>

<!--...-->

后台C#代码：

  private void Button_Click(object sender, RoutedEventArgs e)
        {
            TextBlock text = this.btn.Template.FindName("text1", this.btn) as TextBlock;//查找与此模板中定义的指定名称关联的元素
            text.Text = "One";

            Grid grid = text.Parent as Grid;//获取模板内（text）控件的逻辑父元素
            (grid.Children[1] as TextBlock).Text = "Two";
            (grid.Children[2] as TextBlock).Text = "Three";
            (grid.Children[3] as TextBlock).Text = "Four";
        }