C# – Issue opening doc/docx/excel files in browser(Asp.net, C#)

I am storing some files like PDF, Doc, Docx, xls etc. in the file system.

Now I have to show those files on the browser for the users to view.

So basically a link button is there in a datagrid, upon clicking on which the user will be able to view.

So far my code goes like this

Response.Clear();

// Response.ContentType = "application/pdf";
//Response.ContentType = "application/x-msexcel";       
//Response.ContentType = "application/msword";

string strFilePath = @"C:\test.pdf";
// string strFilePath = @"C:\test.doc";

Response.WriteFile(strFilePath);
Response.End();

This works fine for pdf files but fails for word or excel files. In the browser I am able to view the pdf but the other files are not opening in browser but are asking for the

Save , Open dialog box option. If I click on Open, it will open in a normal window instead of browser.

How can I achieve my target? The browser is IE

Thanks in advance