基于WPF开发txt阅读器

<DockPanel LastChildFill="True">
    <ToolBar DockPanel.Dock="Top">
        <Button Content="👈"/>
        <Button Content="导入"/>
        <Button Content="打开" Click="btnOpenTxt_Click"/>
        <Button Content="保存" Click="btnSaveTxt_Click"/>
        <Button Content="👉"/>
    </ToolBar>
    <UniformGrid DockPanel.Dock="Left" Width="200" Columns="1">
        <ScrollViewer Margin="2">
        </ScrollViewer>
        <ScrollViewer Margin="2">
        </ScrollViewer>
    </UniformGrid>
    <StackPanel DockPanel.Dock="Right" Width="200">
    </StackPanel>
    <GroupBox x:Name="gbTxt" Header="无文件">
        <TextBox x:Name="txt" TextWrapping="Wrap" 
                 VerticalScrollBarVisibility="Auto">    
        </TextBox>
    </GroupBox>
</DockPanel>

private void btnOpenTxt_Click(object sender, RoutedEventArgs e)
{
    var ofd = new OpenFileDialog();
    ofd.Filter = "文本文件(*.txt)|*.txt";
    if (ofd.ShowDialog()!=true)
        return;
    gbTxt.Header = System.IO.Path.GetFileName(ofd.FileName);
    txt.Text = File.ReadAllText(ofd.FileName, Encoding.Unicode);
}

private void btnSaveTxt_Click(object sender, RoutedEventArgs e)
{
    var sfd = new SaveFileDialog();
    sfd.Filter = "文本文件(*.txt)|*.txt";
    if(sfd.ShowDialog()!=true) return;
    File.WriteAllText(sfd.FileName, txt.Text, Encoding.UTF8);
}