DotNetBrowser allows you to save web pages as a file or set of files. You can use Browser.SaveWebPage(String filePath, String dirPath, SavePageType saveType) method to save the current web page. 

Before saving make sure the page is loaded completely.


String filePath = "C:\\SavedPages\\index.html";
String dirPath = "C:\\SavedPages\\resources";
browser.SaveWebPage(filePath, dirPath, SavePageType.COMPLETE_HTML);


Example

MainWindow.xaml

<Window x:Class="WPF.SaveHTML.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:wpf="clr-namespace:DotNetBrowser.WPF;assembly=DotNetBrowser"
Title="MainWindow" Height="350" Width="525" Closing="Window_Closing">
<Grid Name="mainLayout">
<wpf:WPFBrowserView Name="browserView" FinishLoadingFrameEvent="browserView_FinishLoadingFrameEvent"/>
</Grid>
</Window>


MainWindow.xaml.cs

using System;
using System.IO;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using DotNetBrowser;
using DotNetBrowser.WPF;

namespace WPFSaveHTML {
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            browserView.Browser.LoadURL("http://www.google.com");
        }

        private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
        {
            browserView.Dispose();
            browserView.Browser.Dispose();
        }
        private void browserView_FinishLoadingFrameEvent(object sender, DotNetBrowser.Events.FinishLoadingEventArgs e)
        {
            if (e.IsMainFrame)
            {
                String filePath = "C:\\SavedPages\\index.html";
                String dirPath = "C:\\SavedPages\\resources";
                browserView.Browser.SaveWebPage(filePath, dirPath, SavePageType.COMPLETE_HTML);
            }
        }
    }
}