OpenFileDialog dlg = new OpenFileDialog();
dlg.Filter = "Excel Files (*.xls)|*.xls";
dlg.Multiselect = false;
if (dlg.ShowDialog() ?? false)
{
//open the file as a stream
using (Stream stream = dlg.File.OpenRead())
{
//put the stream in the BinaryReader
BinaryReader binary = new BinaryReader(stream);
//Read bytes from the BinaryReader and put them into a byte array.
Byte[] File = binary.ReadBytes((int)stream.Length);
AdminServiceClient adminClient = <get the proxy>;
adminClient.UploadFileCompleted += <hook to completed event>
adminClient.UploadFile(File);
}
}