Create a doc file from gridview or datatable records in asp.net c#

You may (or may not) know this but I'd like to point out that the code that you posted in the below comments is not actually creating a DOC file:

Response.AddHeader("content-disposition", "attachment;filename=" + title + ".doc");
Response.Charset = "";
Response.ContentType = "application/ms-word";
StringWriter sw = new StringWriter();
HtmlTextWriter hw = new HtmlTextWriter(sw);
gvExport.RenderControl(hw);

string style = @"<style> .textmode { mso-number-format:\@; } </style>";
Response.Write(style);
Response.Output.Write(sw.ToString());
Response.Flush();
Response.End();

What this does is it takes a HTML representation of a GridView and saves it as a file with a DOC extension. This is a sort of a workaround because MS Word is able to read and display that HTML file however when opening this file it will throw a warning that says that a file's format and extension are not the same. After you re-save it with MS Word then it will become a "real" DOC file.
Now depending on the situation this may not be an ideal solution, so as an alternative you can check out how to convert a HTML content into a Word document in C#.

Another alternative is this:
http://www.codeproject.com/Articles/91894/HTML-as-a-Source-for-a-DOCX-File
But note that this approach only works for MS Word. In other words the documents created by that approach will appear empty in any other Word application (except in MS Word).