Get Wifi Signal in Windows CE 6.5

 foreach (var ni in NetworkInterface.GetAllNetworkInterfaces())
            {
                //var wzc = ni as WirelessZeroConfigNetworkInterface;
                //if (wzc != null)
                //{
                //    MessageBox.Show("WZC Signal: " + 
                      wzc.SignalStrength.Decibels+":"+wzc.Name);
                //    StrengthType st = wzc.SignalStrength.Strength;
                //    switch (st)
                //    {
                //        case StrengthType.NoSignal:
                //            break;
                //    }
                //    continue;
                //}

                var wni = ni as WirelessNetworkInterface;
                if(wni != null)
                {
                    StrengthType strength = wni.SignalStrength.Strength;
                    switch (strength)
                    {
                        case StrengthType.NoSignal: Program.batteryandtime.WifiUpdate(0);
                            label1.Text = "NoSignal";
                            wifi_strength = 0;
                            break;
                        case StrengthType.NotAWirelessAdapter:
                            Program.batteryandtime.WifiUpdate(0);
                            label1.Text = "NotAWirelessAdapter";
                            wifi_strength = 0;
                            break;
                        case StrengthType.Excellent:Program.batteryandtime.WifiUpdate(3);
                            label1.Text = "Excellent";
                            wifi_strength = 3;
                            break;
                        case StrengthType.VeryGood:Program.batteryandtime.WifiUpdate(3);
                            label1.Text = "VeryGood";
                            wifi_strength = 3;
                            break;
                        case StrengthType.Good:Program.batteryandtime.WifiUpdate(2);
                            label1.Text = "Good";
                            wifi_strength = 2;
                            break;
                        case StrengthType.Low: Program.batteryandtime.WifiUpdate(1);
                            label1.Text = "Low";
                            wifi_strength = 1;
                            break;
                        case StrengthType.VeryLow: Program.batteryandtime.WifiUpdate(1);
                            label1.Text = "VeryLow";
                            wifi_strength = 1;
                            break;
                    }
                   
                                    
                    continue;
                }

                MessageBox.Show("No signal info available");
            }              

Note : To use  OpenNetCF.Net.dll (2.3.12004.0)

Solved Problem:

Control Pannel-> Programs and Features-> Turn Windows Features on or off -> Internet Information Service-> World Wide Web-> Application Development Features->ASP.Net (Checked)

Binary File Uploading by Web Serviece

       [WebMethod]
        public void UploadLogFile(byte[] buffer, string filename)
        {
            if (!Directory.Exists("D:\\EEMS\\EHTLog\\" + DateTime.Now.ToString("yyyyMM")))
            {
                Directory.CreateDirectory("D:\\EEMS\\EHTLog\\" +  
                DateTime.Now.ToString("yyyyMM"));
            }
            BinaryWriter binWriter = new
            BinaryWriter(File.Open("D:\\EEMS\\EHTLog\\" +
            DateTime.Now.ToString("yyyyMM") + "\\" + filename, FileMode.CreateNew,
            FileAccess.ReadWrite));
            binWriter.Write(buffer);
            binWriter.Close();
        }

Convert UT8 to GB2312 (Chinese Encoding)

            string GBInfo = string.Empty;
            Encoding utf8 = Encoding.UTF8;
            Encoding gb2312 = Encoding.GetEncoding("gb2312");
            byte[] UnicodeBytes = utf8.GetBytes(str);
            byte[] AscIIBytes = Encoding.Convert(utf8, gb2312, UnicodeBytes);
            char[] AscIIChars = new char[gb2312.GetCharCount(AscIIBytes, 0,   
            AscIIBytes.Length)];
            gb2312.GetChars(AscIIBytes, 0, AscIIBytes.Length, AscIIChars, 0);
            return AscIIBytes;