Read HTML Embedded .eml files in C#

I am using following code to read .eml files from specific folder :

msg = new CDO.MessageClass();

ADODB.Stream stream = new ADODB.StreamClass();

stream.Open(Type.Missing, ADODB.ConnectModeEnum.adModeUnknown, ADODB.StreamOpenOptionsEnum.adOpenStreamUnspecified, String.Empty, String.Empty);

stream.LoadFromFile(emlFileName);

stream.Flush();

msg.DataSource.OpenObject(stream, "_Stream");

msg.DataSource.Save();

Its working fine for normal emails. But if HTML is embedded in email then it is giving "[Text Box: value ]" in the message body for the values that is entered in textbox.