How to call a method from DataAccessLayer

// Read the file and convert it to Byte Array
string filePath = FileUpload2.PostedFile.FileName;
string filename = Path.GetFileName(filePath);
string ext = Path.GetExtension(filename);
string contenttype = String.Empty;

//Set the contenttype based on File Extension
switch (ext)
{


    case ".doc":
        contenttype = "application/vnd.ms-word";
        break;
    case ".docx":
        contenttype = "application/vnd.ms-word";
        break;
    case ".pdf":
        contenttype = "application/vnd.ms-word";
        break;

}
if (contenttype != String.Empty)
{

    Stream fs = FileUpload1.PostedFile.InputStream;
    BinaryReader br = new BinaryReader(fs);
    Byte[] bytes = br.ReadBytes((Int32)fs.Length);

    //insert the file into database
    string strQuery = "insert into PARTY(Party_Manifesto)" +
       " values (@Party_Manifesto)";
    SqlCommand cmd = new SqlCommand(strQuery);
    //cmd.Parameters.Add("@Candidate_Image", SqlDbType.VarChar).Value = filename;
    //cmd.Parameters.Add("@ContentType", SqlDbType.VarChar).Value
    //  = contenttype;
    cmd.Parameters.Add("@Party_Manifesto", SqlDbType.Binary).Value = bytes;
    InsertUpdateData(cmd);
    lblmsg.ForeColor = System.Drawing.Color.Green;
    lblmsg.Text = "File Uploaded Successfully";
}
else
{
    lblmsg.ForeColor = System.Drawing.Color.Red;
    lblmsg.Text = "File format not recognised." +
      " Upload document/pdf/doc/docs formats";
}