c# aes ctr implement works on vs2017/uwp , seen testRun for usage example.

AesCtr.cs

using System.Security.Cryptography;
using System.Diagnostics;
using System;
using System.Runtime.InteropServices.WindowsRuntime;

namespace abc {
    public sealed class AesCtr {
        public static void testRun() {
            for (var i2 = 0; i2 < 3; i2++) {
                var outputV = Encrypt(new byte[32], new byte[16], new byte[30]);
                for (var i = 0; i < 30; i++) {
                    Debug.WriteLine("runTest " + i.ToString() + " " + outputV[i].ToString());
                }
            }
        }
        public static byte[] Encrypt([ReadOnlyArray]byte[] psk, [ReadOnlyArray]byte[] iv, [ReadOnlyArray]byte[] inData) {
            var aesObj = Aes.Create();
            aesObj.Mode = CipherMode.ECB;
            aesObj.Padding = PaddingMode.None;
            var zeroIv = new byte[16];
            var Encryptor = aesObj.CreateEncryptor(psk, zeroIv);
            var counter = new byte[16]; // copy input iv (do not modify it)
            for (var i = 0; i < 16; i++) {
                counter[i] = iv[i];
            }
            var ctrOut = new byte[16];
            var output = new byte[inData.Length];
            var pos = 0;
            while (true) {
                if (pos >= inData.Length) {
                    break;
                }
                Encryptor.TransformBlock(counter, 0, 16, ctrOut, 0);
                for (var i = 0; i < 16; i++) {
                    if (pos >= inData.Length) {
                        break;
                    }
                    output[pos] = (byte)(inData[pos] ^ ctrOut[i]);
                    pos++;
                }
                // increment counter
                for (var i = 15; i >= 0; i--) {
                    counter[i]++;
                    if (counter[i] != 0) {
                        break;
                    }
                }
            }
            return output;
        }
    }
}

Ok thank