How to prevent entry of HTML into ASP.NET Web form text box

Answer 1

ave a look here http://msdn.microsoft.com/en-us/library/ff649310.aspx

you can put a blanket statement in the web config ValidateRequest = true will check all user input and throw an error if a user inserts something with bad characters.

If you need to allow some html tags then you will need to roll your own.

Answer 2

The page will, by default, prevent users from posting HTML or script in textboxes or textareas. See MSDN

Answer 3

You can use a method to clean HTML codes from entry like:

public static string ClearHTML(string Str, Nullable<int> Character)
{
    string MetinTxtRegex = Regex.Replace(Str, "<(.|\n)+?>", " ");

    string MetinTxtSubStr = string.Empty;

    if (Character.HasValue)
    {
        if (MetinTxtRegex.Length > Character)
        {
            MetinTxtSubStr = MetinTxtRegex.Substring(0, Character.Value);
            MetinTxtSubStr = MetinTxtSubStr.Substring(0, MetinTxtSubStr.LastIndexOf(" ")) + "...";
        }
        else
        {
            MetinTxtSubStr = MetinTxtRegex;
        }
    }
    else
    {
        MetinTxtSubStr = MetinTxtRegex;
    }
    return MetinTxtSubStr;
}

Answer 4

I've used:

HttpUtility.HtmlEncode();

More info here.