回答編集履歴

- `TextBlock`は軽量コンポーネントとして`FrameworkElement`派生なので、`Template`等がなくあんまり凝ったことはできないです。

-

- 今の解釈でこういうことかな？？というサンプルを作りました。

- `Label` `TextBox` `Button`はいろいろ置いてあるよって程度の意味です。

- `Canvas`ベースなのも特別意味はありません。

-

- 添付ビヘイビアはいろいろとガバガバなので、このままでは使い物にならないだろうと思います。

-

- ```xaml

- <Window

- x:Class="Questions264652.MainWindow"

- xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"

- xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"

- xmlns:local="clr-namespace:Questions264652"

- Width="800"

- Height="450">

- <Grid>

- <Grid.RowDefinitions>

- <RowDefinition />

- <RowDefinition />

- </Grid.RowDefinitions>

- <Grid.ColumnDefinitions>

- <ColumnDefinition />

- <ColumnDefinition />

- </Grid.ColumnDefinitions>

- <GroupBox Header="今の状態">

- <Canvas>

- <TextBlock

- Canvas.Left="35"

- Canvas.Top="24"

- Text="ほげほげ" />

- <TextBlock

- Canvas.Left="177"

- Canvas.Top="49"

- Text="ふがふが" />

- <Label

- Canvas.Left="114"

- Canvas.Top="122"

- Content="Label" />

- <TextBox

- Canvas.Left="194"

- Canvas.Top="126"

- Text="TextBox" />

- <Button

- Canvas.Left="282"

- Canvas.Top="125"

- Content="Button" />

- </Canvas>

- </GroupBox>

-

- <GroupBox Grid.Column="1" Header="こうなるといいなの状態">

- <Canvas>

- <TextBlock Canvas.Left="35" Canvas.Top="24">

- <InlineUIContainer BaselineAlignment="Center">

- <Image Width="20" Source="https://teratail-v2.storage.googleapis.com/uploads/avatars/u13/132786/KnkDDC5A_thumbnail_32x32.jpg" />

- </InlineUIContainer>

- <Run>ほげほげ</Run>

- <Bold>!!</Bold>

- </TextBlock>

- <TextBlock Canvas.Left="177" Canvas.Top="49">

- <InlineUIContainer BaselineAlignment="Center">

- <Image Width="20" Source="https://teratail-v2.storage.googleapis.com/uploads/avatars/u13/132786/KnkDDC5A_thumbnail_32x32.jpg" />

- </InlineUIContainer>

- <Run>ふがふが</Run>

- <Bold>!!</Bold>

- </TextBlock>

- <Label

- Canvas.Left="114"

- Canvas.Top="122"

- Content="Label" />

- <TextBox

- Canvas.Left="194"

- Canvas.Top="126"

- Text="TextBox" />

- <Button

- Canvas.Left="282"

- Canvas.Top="125"

- Content="Button" />

- </Canvas>

- </GroupBox>

-

- <GroupBox Grid.Row="1" Header="テンブレート">

- <Canvas>

- <Canvas.Resources>

- <Style TargetType="ContentControl">

- <Setter Property="Template">

- <Setter.Value>

- <ControlTemplate TargetType="ContentControl">

- <TextBlock>

- <InlineUIContainer BaselineAlignment="Center">

- <Image Width="20" Source="https://teratail-v2.storage.googleapis.com/uploads/avatars/u13/132786/KnkDDC5A_thumbnail_32x32.jpg" />

- </InlineUIContainer>

- <Run Text="{TemplateBinding Content}" />

- <Bold>!!</Bold>

- </TextBlock>

- </ControlTemplate>

- </Setter.Value>

- </Setter>

- </Style>

- </Canvas.Resources>

- <ContentControl

- Canvas.Left="35"

- Canvas.Top="24"

- Content="ほげほげ" />

- <ContentControl

- Canvas.Left="177"

- Canvas.Top="49"

- Content="ふがふが" />

- <Label

- Canvas.Left="114"

- Canvas.Top="122"

- Content="Label" />

- <TextBox

- Canvas.Left="194"

- Canvas.Top="126"

- Text="TextBox" />

- <Button

- Canvas.Left="282"

- Canvas.Top="125"

- Content="Button" />

- </Canvas>

- </GroupBox>

-

- <GroupBox

- Grid.Row="1"

- Grid.Column="1"

- Header="添付ビヘイビア">

- <Canvas>

- <Canvas.Resources>

- <InlineUIContainer

- x:Key="image"

- x:Shared="False"

- BaselineAlignment="Center">

- <Image Width="20" Source="https://teratail-v2.storage.googleapis.com/uploads/avatars/u13/132786/KnkDDC5A_thumbnail_32x32.jpg" />

- </InlineUIContainer>

- <Bold x:Key="exclamation" x:Shared="False">!!</Bold>

-

- <Style TargetType="TextBlock">

- <Setter Property="local:AddInlineBehavior.Before" Value="{StaticResource image}" />

- <Setter Property="local:AddInlineBehavior.After" Value="{StaticResource exclamation}" />

- <Setter Property="local:AddInlineBehavior.Use" Value="True" />

- </Style>

- </Canvas.Resources>

-

- <TextBlock

- Canvas.Left="35"

- Canvas.Top="24"

- Text="ほげほげ" />

- <TextBlock

- Canvas.Left="177"

- Canvas.Top="49"

- Text="ふがふが" />

- <Label

- Canvas.Left="114"

- Canvas.Top="122"

- Content="Label" />

- <TextBox

- Canvas.Left="194"

- Canvas.Top="126"

- Text="TextBox" />

- <Button

- Canvas.Left="282"

- Canvas.Top="125"

- Content="Button" />

- </Canvas>

- </GroupBox>

- </Grid>

- </Window>

- ```

-

- ```C#

- using System.Windows;

- using System.Windows.Controls;

- using System.Windows.Documents;

-

- namespace Questions264652

- {

- public class AddInlineBehavior

- {

- public static DependencyProperty UseProperty

- = DependencyProperty.RegisterAttached("Use", typeof(bool), typeof(AddInlineBehavior),

- new PropertyMetadata(false, OnUseChanged));

- public static void SetUse(DependencyObject obj, bool value) => obj.SetValue(UseProperty, value);

- public static bool GetUse(DependencyObject obj) => (bool)obj.GetValue(UseProperty);

- private static void OnUseChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)

- {

- if(d is TextBlock textBlock)

- {

- if((bool)e.NewValue)

- {

- var tmp = textBlock.Text;

- textBlock.Inlines.Clear();

- if(GetBefore(textBlock) is Inline before)

- {

- textBlock.Inlines.Add(before);

- textBlock.Inlines.Add(new Run(" "));

- }

- textBlock.Inlines.Add(new Run(tmp));

- if(GetAfter(textBlock) is Inline after)

- {

- textBlock.Inlines.Add(new Run(" "));

- textBlock.Inlines.Add(after);

- }

- }

- }

- }

-

- public static DependencyProperty BeforeProperty

- = DependencyProperty.RegisterAttached("Before", typeof(Inline), typeof(AddInlineBehavior),

- new PropertyMetadata(null));

- public static void SetBefore(DependencyObject obj, Inline value) => obj.SetValue(BeforeProperty, value);

- public static Inline GetBefore(DependencyObject obj) => (Inline)obj.GetValue(BeforeProperty);

-

- public static DependencyProperty AfterProperty

- = DependencyProperty.RegisterAttached("After", typeof(Inline), typeof(AddInlineBehavior),

- new PropertyMetadata(null));

- public static void SetAfter(DependencyObject obj, Inline value) => obj.SetValue(AfterProperty, value);

- public static Inline GetAfter(DependencyObject obj) => (Inline)obj.GetValue(AfterProperty);

- }

- }

- ```