OpenFileDialog openFileDialog = new OpenFileDialog();
openFileDialog.Filter = "Text File (.txt)|*.txt";
bool? useClick = openFileDialog.ShowDialog();
if (useClick == true)
{
var stream = openFileDialog.File.OpenRead();
stream.Seek(0, System.IO.SeekOrigin.Begin);
gcSpreadSheet1.Sheets[0].OpenTextFile(stream, GrapeCity.Windows.SpreadSheet.Data.TextFileOpenFlags.None, "\r", ",", "");
//gcSpreadSheet1.Sheets[0].OpenTextFile(stream, GrapeCity.Windows.SpreadSheet.Data.TextFileOpenFlags.None, "\r", ",", "", System.Text.Encoding.UTF8);
//gcSpreadSheet1.OpenTextFile(0, stream, GrapeCity.Windows.SpreadSheet.Data.TextFileOpenFlags.None, "\r", ",", "");
stream.Dispose();
}