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.

C#

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

VB.NET

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



Example

MainWindow.xaml

<Window x:Class="WPFSaveHTML.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>


C#

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);
            }
        }
    }
}

VB.NET

MainWindow.xaml.vb

Imports System.ComponentModel
Imports DotNetBrowser
Imports DotNetBrowser.Events

Namespace WPFSaveHTML
    Class MainWindow
        Sub New()
            InitializeComponent()
            browserView.Browser.LoadURL("http://www.google.com")
        End Sub

        Private Sub Window_Closing(sender As Object, e As CancelEventArgs)
            browserView.Dispose()
            browserView.Browser.Dispose()
        End Sub

        Private Sub browserView_FinishLoadingFrameEvent(sender As Object, e As FinishLoadingEventArgs)
            IF (e.IsMainFrame) Then
                Dim filePath As String = "C:\SavedPages\index.html"
                Dim dirPath As String = "C:\SavedPages\resources"
                browserView.Browser.SaveWebPage(filePath, dirPath, SavePageType.COMPLETE_HTML)
            End If
        End Sub
    End Class
End Namespace