RichTextBox.Selection Property

Property Value

Type: System.Windows.Documents.TextSelection
A TextSelection that represents the selected text in the RichTextBox.

<!--Create a RichTextBox and three buttons.-->
<StackPanel>
    <RichTextBox x:Name="MyRTB" Width="600" Height="400" />
    <StackPanel Orientation="Horizontal" HorizontalAlignment="Center">
        <Button Content="Bold" Height="30" Margin="2" Width="50" Click="BtnBold_Click" />
        <Button Content="Italic" Height="30" Margin="2" Width="50" Click="BtnItalic_Click" />
        <Button Content="Underline" Height="30" Margin="2" Width="65" Click="BtnUnderline_Click" />
    </StackPanel>
</StackPanel>

'Set Bold formatting to selected content
Private Sub BtnBold_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
    If MyRTB IsNot Nothing Then
        If TypeOf MyRTB.Selection.GetPropertyValue(Run.FontWeightProperty) Is FontWeight _
            AndAlso (CType(MyRTB.Selection.GetPropertyValue(Run.FontWeightProperty), FontWeight) = FontWeights.Normal) Then
            MyRTB.Selection.ApplyPropertyValue(Run.FontWeightProperty, FontWeights.Bold)
        Else
            MyRTB.Selection.ApplyPropertyValue(Run.FontWeightProperty, FontWeights.Normal)
        End If
    End If
End Sub


'Set Italic formatting to selected content
Private Sub BtnItalic_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
    If MyRTB IsNot Nothing Then
        If TypeOf MyRTB.Selection.GetPropertyValue(Run.FontStyleProperty) Is FontStyle _
            AndAlso (CType(MyRTB.Selection.GetPropertyValue(Run.FontStyleProperty), FontStyle) = FontStyles.Normal) Then
            MyRTB.Selection.ApplyPropertyValue(Run.FontStyleProperty, FontStyles.Italic)
        Else
            MyRTB.Selection.ApplyPropertyValue(Run.FontStyleProperty, FontStyles.Normal)
        End If
    End If
End Sub


'Set Underline formatting to selected content
Private Sub BtnUnderline_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
    If (Not (MyRTB) Is Nothing) Then
        If (MyRTB.Selection.GetPropertyValue(Run.TextDecorationsProperty) Is Nothing) Then
            MyRTB.Selection.ApplyPropertyValue(Run.TextDecorationsProperty, TextDecorations.Underline)
        Else
            MyRTB.Selection.ApplyPropertyValue(Run.TextDecorationsProperty, Nothing)
        End If
    End If
End Sub

//Set Bold formatting to selected content
private void BtnBold_Click(object sender, RoutedEventArgs e)
{
    if (MyRTB != null)
    {
        if (MyRTB.Selection.GetPropertyValue(Run.FontWeightProperty) is FontWeight && ((FontWeight)MyRTB.Selection.GetPropertyValue(Run.FontWeightProperty)) == FontWeights.Normal)
            MyRTB.Selection.ApplyPropertyValue(Run.FontWeightProperty, FontWeights.Bold);
        else
            MyRTB.Selection.ApplyPropertyValue(Run.FontWeightProperty, FontWeights.Normal);

    }

}
//<SnippetItalic>
//Set Italic formatting to selected content
private void BtnItalic_Click(object sender, RoutedEventArgs e)
{
    if (MyRTB != null)
    {
        if (MyRTB.Selection.GetPropertyValue(Run.FontStyleProperty) is FontStyle && ((FontStyle)MyRTB.Selection.GetPropertyValue(Run.FontStyleProperty)) == FontStyles.Normal)
            MyRTB.Selection.ApplyPropertyValue(Run.FontStyleProperty, FontStyles.Italic);
        else
            MyRTB.Selection.ApplyPropertyValue(Run.FontStyleProperty, FontStyles.Normal);
    }


}

//Set Underline formatting to selected content
private void BtnUnderline_Click(object sender, RoutedEventArgs e)
{
    if (MyRTB != null)
    {
        if (MyRTB.Selection.GetPropertyValue(Run.TextDecorationsProperty) == null)
            MyRTB.Selection.ApplyPropertyValue(Run.TextDecorationsProperty, TextDecorations.Underline);
        else
            MyRTB.Selection.ApplyPropertyValue(Run.TextDecorationsProperty, null);
    }

}