Scrollbar for RichTextBox WPF

Question

I have created a RichTextBox with a Fixed Width and Height (Size of A4 Sheet). I would like to scroll the text vertically when the data goes outside the height. I am able to achieve the vertical scroll via mouse wheel by setting the VerticalScrollBarVisibility property to Hidden. Until this everything works fine.

If I change the VerticalScrollBarVisibility property to "Visible", it display the vertical scrollbar attached to the RichTextBox. Since, I am using the fixed width for the RichtextBox, the Scrollbar does not appear at the right side of the window. However, I would like to have a separate Scrollbar to the right of my window (just like every browsers). I have added a separate Vertical Scrollbar to the window. Now the question is, how can I link the Scrollbar event to RichTextBox scrolling?.

     <Style x:Key="RichTxtStyle"  TargetType="{x:Type RichTextBox}">
        <Setter Property="VerticalScrollBarVisibility" Value="Hidden"/>
        <Setter Property="HorizontalScrollBarVisibility" Value="Disabled"/>
        <Setter Property="AcceptsReturn"  Value="True"/>            
        <Setter Property="Margin" Value="40,0,40,0"/>
        <Setter Property="Padding" Value="50,50,50,50"/>
        <Setter Property="Width" Value="827"/>
        <Setter Property="MinHeight"  Value="1169"/>
        <Setter Property="BorderThickness" Value="0"/>           
    </Style>

Here is the Scrollbar object

 <ScrollBar x:Name="VerticalScroll"   Grid.Row="1" Grid.Column="1" Orientation="Vertical" ValueChanged="VerticalScroll_ValueChanged"/>

Below is the event, I tried. This is where I am totally lost?.

        private void VerticalScroll_ValueChanged(object sender, RoutedPropertyChangedEventArgs<double> e)
    {
        double offset = e.NewValue;
        RichTxtBx.ScrollToVerticalOffset(offset);
    }

Answer 1

Correct me if I am wrong, but the approach of @meysam asadi is offering you to wrap RichTextBox by a ScrollViewer. Sometimes this is is not desired because of decreased perfomance. Instead you should simply use:

<Window x:Class="stackvoerflow_65766040.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:stackvoerflow_65766040"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <RichTextBox VerticalScrollBarVisibility="Visible" x:Name="rtbMain">
            
        </RichTextBox>
    </Grid>
</Window>

Then you are able to use the methods ScrollToEnd(), ScrollToVerticalOffset(double offset) and so on of "rtbMain".

To catch the ScollChanged event you use ScrollViewer.ScrollChanged="rtbMain_ScrollChanged" like this:

<Window x:Class="stackvoerflow_65766040.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:stackvoerflow_65766040"
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <RichTextBox VerticalScrollBarVisibility="Visible" x:Name="rtbMain"
                     ScrollViewer.ScrollChanged="rtbMain_ScrollChanged">
        </RichTextBox>
    </Grid>
</Window>

Code-behind:

using System.Windows;
using System.Windows.Controls;

namespace stackvoerflow_65766040
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void rtbMain_ScrollChanged(object sender, ScrollChangedEventArgs e)
        {

        }
    }
}

If you you want assign the events of ScrollViewer from RichTextBox in code-behind aswell you should take a brief look at this: WPF accessing scrollviewer of a listview codebehind.

Answer 2

I think this code is useful.

<ScrollViewer VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Disabled">
   <RichTextBox Style="{StaticResource RichTxtStyle}">
               
   </RichTextBox>
</ScrollViewer>