C# copy data from html table in table format in textbox

In C# I have a WPF textbox in my form, a added a contextmenu:
  <TextBox.ContextMenu>
            <ContextMenu>
                <MenuItem Header="Cut" Click="menu_cut"  />
                <MenuItem Header="Copy" Click="menu_copy"  />
                <MenuItem Header="Paste" Click="menu_paste"  />
            </ContextMenu>
 </TextBox.ContextMenu>
I have html table in browser that look as a picture "file1" in attachment
when I  copy to *.doc I got as a picture "file2"

If I use code:
 private void menu_paste(object sender, RoutedEventArgs e)
        {
            if (Clipboard.GetDataObject().GetDataPresent(DataFormats.Text) == true)
            {
                 memo_text.Text = memo_text.Text + Clipboard.GetText(TextDataFormat.Text);
               
            }
        }

I got a picture "file3"

If I use code:
 private void menu_paste(object sender, RoutedEventArgs e)
        {
            if (Clipboard.GetDataObject().GetDataPresent(DataFormats.Text) == true)
            {
                 memo_text.Text = memo_text.Text + Clipboard.GetText(TextDataFormat.Html);
               
            }
        }

I got a picture "file5"

when I use *.doc intermediately and  copy to textbox, result as picture "file4"
How can I get format as "file4" directly?
file1.JPG
file2.JPG
file3.JPG
file4.JPG
file5.JPG