TextBlock Control

The TextBlock control serves as a specialized element for rendering text within WPF appplications. It offers enhanced functionality compared to Label controls, including advanced formatting options and improved performence.

Key features of TextBlock:

• Text Formatting: Supports font styles, sizes, bold, italic, and other visual attributes.
• Line Wrapping: Automatically wraps long text without truncation.
• Inline Elements: Allows embedding hyperlinks, icons, and other inline content.
• Rich Text Support: Displays formatted text with varying fonts, colors, and decorations.
• Performance Optimization: Efficient handling of large text volumes.

Core properties include:

• FontWeight: Controls text thickness (Normal, Bold).
• FontStyle: Applies italic or normal styling.
• FontFamily: Specifies the typeface (e.g., Arial, Microsoft YaHei UI).
• Text: Sets or retrieves displayed text.
• TextWrapping: Determines line breaking behavior (NoWrap, Wrap).
• Foreground: Sets the text color.
• Background: Defines background color.
• Padding: Adds space between content and border.
• TextAlignment: Aligns text horizontally (Left, Right, Center).
• TextTrimming: Handles overflow with ellipsis or clipping.
• Inlines: Collection for Run elements with individual styling capabilities.

Example XAML:

<WrapPanel Margin="10">
    <TextBlock Text="Basic TextBlock" Margin="5"/>
    <TextBlock FontWeight="Bold" Text="Bold Text" Margin="5"/>
    <TextBlock FontStyle="Italic" Text="Italic Text" Margin="5"/>
    <TextBlock FontFamily="Microsoft YaHei UI" Text="YaHei Font" Margin="5"/>
    <TextBlock FontSize="30" Text="Large Text" Margin="5"/>
    <TextBlock Foreground="Red" Text="Red Text" Margin="5"/>
    <TextBlock Foreground="Yellow" Background="Red" Text="Colored Background" Margin="5"/>
    <TextBlock Foreground="Yellow" Background="Red" Text="Padded Text" Padding="10" Margin="5"/>
    <TextBlock Background="LightGray" Height="25" Margin="5">
        <Run Foreground="Red">First part</Run>
        <Run Foreground="Green">Second part</Run>
        <Run Foreground="Blue">Third part</Run>
    </TextBlock>
    <Grid Width="150" Height="100" Background="LightGoldenrodYellow" Margin="5">
        <TextBlock TextWrapping="Wrap" Margin="10" Text="This demonstrates TextWrapping property"/>
    </Grid>
</WrapPanel>

TextBox Control

The TextBox control facilitates user input of textual data. It inherits from TextBoxBase which itself extends Control.

TextBoxBase Properties

• VerticalScrollBarVisibility: Controls vertical scrollbar visibility.
• HorizontalScrollBarVisibility: Manages horizontal scrollbar visibility.
• AcceptsReturn: Enables newline insertion via Enter key.
• AcceptsTab: Controls tab character insertion.
• IsReadOnlyCaretVisible: Shows caret in read-only mode.
• SelectionOpacity: Sets selection transparency.
• IsUndoEnabled: Enables undo functionality.
• UndoLimit: Limits number of undo operations.
• AutoWordSelection: Auto-selects words.
• SelectionBrush: Paints selected text area.
• IsReadOnly: Locks editing capability.
• CaretBrush: Configures cursor appearance.
• IsInactiveSelectionHighlightEnabled: Highlights selections when inactive.

Events:

• TextChanged: Triggers upon content modification.
• SelectionChanged: Fires when selection range changes.

TextBox Specific Properties

• MinLines: Minimum visible rows.
• MaxLines: Maximum visible rows.
• CharacterCasing: Controls character case (Normal, Lower, Upper).
• MaxLength: Limits manual input length.
• TextAlignment: Aligns text (Left, Right, Center).
• CaretIndex: Current cursor position.
• SelectionLength: Number of selected characters.
• SelectionStart: Starting index of selection.
• Typography: Applies typographic variations.
• LineCount: Total lines in textbox.
• TextDecorations: Applies text effects like underline.
• SelectedText: Retrieves selected content.
• TextWrapping: Controls word wrapping.

Example XAML:

<Grid Margin="20">
    <Grid.RowDefinitions>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="Auto"/>
        <RowDefinition Height="Auto"/>
    </Grid.RowDefinitions>
    
    <TextBox x:Name="inputBox" Grid.Row="0" Margin="5" Width="200" TextAlignment="Center" Text="Enter Name"
             GotFocus="OnGotFocus" LostFocus="OnLostFocus"/>
    
    <TextBox x:Name="readOnlyBox" Grid.Row="1" Margin="5" Width="200" Text="Read Only Box" IsReadOnly="True"/>
    
    <TextBox x:Name="multiLineBox" Grid.Row="2" Margin="5" Width="200" Height="80" TextWrapping="Wrap"
             Text="Multi-line text box example" GotFocus="OnGotFocus" LostFocus="OnLostFocus"/>
    
    <TextBox x:Name="limitBox" Grid.Row="3" Margin="5" Width="200" MaxLength="10" Text="Max 10 chars"
             GotFocus="OnGotFocus" LostFocus="OnLostFocus"/>
</Grid>

Code-behind:

private void OnGotFocus(object sender, RoutedEventArgs e)
{
    var textBox = sender as TextBox;
    if (textBox != null) textBox.Text = string.Empty;
}

private void OnLostFocus(object sender, RoutedEventArgs e)
{
    var textBox = sender as TextBox;
    if (textBox == null) return;
    
    switch (textBox.Name)
    {
        case "inputBox":
            textBox.Text = "Enter Name";
            break;
        case "multiLineBox":
            textBox.Text = "Multi-line text box example";
            break;
        case "limitBox":
            textBox.Text = "Max 10 chars";
            break;
    }
}

RichTextBox Control

RichTextBox enables complex document creation with formatting, images, and links. It supports FlowDocument for rich content management.

Constructors:

• public RichTextBox(): Default constructor.
• public RichTextBox(FlowDocument document): Initializes with document.

Properties:

• Document: Gets or sets the underlying FlowDocument.
• IsDocumentEnabled: Enables/disables document mode.
• Selection: Current text selection object.
• CaretPosition: Cursor location within document.

Methods:

• GetNextSpellingErrorPosition: Finds next spelling error.
• GetPositionFromPoint: Locates text position from coordinates.
• GetSpellingError: Retrieves spelling error at position.
• GetSpellingErrorRange: Gets range containing spelling error.
• ShouldSerializeDocument: Indicates if document should be serialized.

Example XAML:

<RichTextBox x:Name="richTextBox" Margin="10">
    <FlowDocument>
        <Paragraph>
            <Run FontWeight="Bold">RichTextBox Sample</Run>
        </Paragraph>
        <Paragraph>
            <Run>Advanced text editing capabilities.</Run>
        </Paragraph>
        <Paragraph>
            <Run>You can apply different fonts, styles, and colors here.</Run>
        </Paragraph>
    </FlowDocument>
</RichTextBox>

ToolTip Control

ToolTip displays contextual help messages attached to other controls. It requires a parent control and appears on hover.

Properties:

• IsOpen: Controls visibility state.
• StaysOpen: Prevents automatic closure.
• Placement: Position relative to target.
• HorizontalOffset, VerticalOffset: Adjust positioning.
• HasDropShadow: Adds shadow effect.

Events:

• Opened: Triggered when shown.
• Closed: Triggered when hidden.

Example XAML:

<Button Content="Hover Me" HorizontalAlignment="Center" VerticalAlignment="Center">
    <Button.ToolTip>
        <ToolTip Content="This is a ToolTip."/>
    </Button.ToolTip>
</Button>

Popup Control

Popup creates floating windows that can contain any UI elements. Unlike ToolTip, it supports complex layouts.

Properties:

• IsOpen: Toggles visibility.
• PlacementTarget: Target element for positioning.
• Placement: Alignment options.
• HorizontalOffset, VerticalOffset: Offset values.
• StaysOpen: Keeps popup open after focus loss.
• Child: Single child element.
• PopupAnimation: Animation effect on open/close.

Events:

• Opened: Raised when popup opens.
• Closed: Raised when popup closes.

Example XAML:

<StackPanel Orientation="Horizontal" HorizontalAlignment="Center" VerticalAlignment="Center">
    <CheckBox x:Name="menuToggle" Content="Show Menu" Height="30" Margin="5" ToolTip="Toggle menu" Checked="OnMenuToggle"/>
    <Popup Name="contextMenu" IsOpen="{Binding IsChecked, ElementName=menuToggle}" 
           PlacementTarget="{Binding ElementName=menuToggle}" StaysOpen="True">
        <Border BorderThickness="1" Background="LightBlue">
            <StackPanel>
                <Button Content="Option 1" Click="OnMenuItemClick"/>
                <Button Content="Option 2" Click="OnMenuItemClick"/>
                <Button Content="Option 3" Click="OnMenuItemClick"/>
            </StackPanel>
        </Border>
    </Popup>
</StackPanel>

Code-behind:

private void OnMenuItemClick(object sender, RoutedEventArgs e)
{
    var button = sender as Button;
    if (button == null) return;
    
    switch (button.Content.ToString())
    {
        case "Option 1":
            MessageBox.Show("Option 1 selected");
            contextMenu.IsOpen = false;
            break;
        case "Option 2":
            MessageBox.Show("Option 2 selected");
            contextMenu.IsOpen = false;
            break;
        case "Option 3":
            MessageBox.Show("Option 3 selected");
            contextMenu.IsOpen = false;
            break;
    }
}

private void OnMenuToggle(object sender, RoutedEventArgs e)
{
    var checkBox = sender as CheckBox;
    contextMenu.IsOpen = checkBox?.IsChecked == true;
}

Image Control

The Image control renders various image formats (BMP, GIF, JPG, PNG, TIFF, etc.). For animated GIFs, third-party libraries like WpfAnimatedGif are required.

Properties:

• Stretch: Scaling behavior (None, Fill, Uniform, UniformToFill).
• StretchDirection: Scaling constraints (UpOnly, DownOnly, Both).
• Source: Image source.
• BaseUri: Base URI for image resources.

Events:

• DpiChanged: Triggers when display DPI changes.
• ImageFailed: Occurs on loading failure.

Example XAML:

<Image Width="200" Height="150" Stretch="Uniform" Source="/Images/meimei.png" />

Ensure image build action is set to 'Copy Always' or 'Copy If Newer'.