Using C# Code
string htmlContent = System.IO.File.ReadAllText("Url of your html file");
lblOnlyText.Text = System.Text.RegularExpressions.Regex.Replace(htmlContent, "<[^>]*>", "");
Using VB.Net Code
Dim htmlContent As String = System.IO.File.ReadAllText("Url of your html file")
lblOnlyText.Text = System.Text.RegularExpressions.Regex.Replace(htmlContent, "<[^>]*>", "")