Do while loop error

string IP = ConfigurationManager.AppSettings["ServerIP"].ToString();
int Port = Convert.ToInt32(ConfigurationManager.AppSettings["Port"].ToString());
int i = 0;
do
{
string Barcode = lstBarcode.Items[i].ToString();
txtResult.Text += GetTime() + " Barcode: " + Barcode + " scanned.";
dbConnect.AddResponse(comIpAddress.SelectedItem.ToString(), Barcode, "Barcode scanned");
//Gets random response, this will be replaced by server response. 

string barcode = "R1:" + txtBarcode.Text + "\r";
TcpClient clientSocket = new TcpClient();
clientSocket.Connect(IP, Port);
NetworkStream serverStream = clientSocket.GetStream();
byte[] outStream = Encoding.ASCII.GetBytes(barcode);
serverStream.Write(outStream, 0, outStream.Length);
serverStream.Flush();
byte[] inStream = new byte[10025];
serverStream.Read(inStream, 0, (int)clientSocket.ReceiveBufferSize);
string returndata = System.Text.Encoding.ASCII.GetString(inStream);
returndata = returndata.Remove(6);
if (returndata == "I1:005")
{
txtResult.Text += GetTime() + " Barcode: " + Barcode + " had not enough points.";
dbConnect.AddResponse(comIpAddress.SelectedItem.ToString(), Barcode, "Barcode Ignored");
returndata = "";
}
//Open Barcode
else if (returndata == "G1:005")
{
txtResult.Text += GetTime() + " Opening gate for barcode: " + Barcode;
dbConnect.AddResponse(comIpAddress.SelectedItem.ToString(), Barcode, "Barcode Success");
returndata = "";
}
i++;
} while (i <count);

 

[15:40:21:265] Program started.
[15:40:23:687] Added 3 Barcodes
[15:40:24:734] Barcode: 4113530275052234 scanned.
[15:40:25:437] Opening gate for barcode: 4113530275052234
[15:40:25:437] Barcode: 4335964778311252 scanned.
[15:40:26:46] Barcode: 7771230666718299 scanned. 

 

[15:40:21:265] Program started.
[15:40:23:687] Added 3 Barcodes
[15:40:24:734] Barcode: 4113530275052234 scanned.
[15:40:25:437] Opening gate for barcode: 4113530275052234
[15:40:25:437] Barcode: 4335964778311252 scanned.
[15:40:26:46] Opening gate for barcode: 4335964778311252
[15:40:26:46] Barcode: 7771230666718299 scanned.
[15:40:27:257] Opening gate for barcode: 7771230666718299