Validate pdf file with file name like ID using C# in ASP.Net

 Hello Guys i am validating a pdf file that is working fine.. now i am trying tovalidate a pdf file with id..our reQuirement is we are uploading a file when some conditions are true.. example if the person has an id den only he can upload.. now i need to validate the pdf file with id..filename should have certain parametreslike id that can be validated..

protected void btnSubmit_Click(object sender, EventArgs e)
{
    var flag = false;
    try
    {
        if (fileUpload.HasFile)
        {
            var extension = System.IO.Path.GetExtension(fileUpload.FileName);
            if (extension.ToLower() == ".pdf")
            {
                using (var conn = new SqlConnection(dbString))
                {
                    //line of code
                }
            }
            else
            {
                label.Text = "Please upload pdf files..";
            }
        }
        else
        {
            if (!fileUpload.HasFile)
            {
                label.Text = "Please upload the file..";
            }
        }
    }
    catch (exception ex)
    {
        lblStatus.Text = ex.Message;
    }
}

How do i change my code so that i can add a id as a parameter to validate please help??

any ideas??