Enable TRT EP for C# (#7482)

* enabled TRT EP for C#

* Fix potential leak

csharp/src/Microsoft.ML.OnnxRuntime/SessionOptions.cs

@@ -38,6 +38,7 @@ namespace Microsoft.ML.OnnxRuntime
     {
         // Delay-loaded CUDA or cuDNN DLLs. Currently, delayload is disabled. See cmake/CMakeLists.txt for more information.
         private static string[] cudaDelayLoadedLibs = { };
+        private static string[] trtDelayLoadedLibs = { };
 
         #region Constructor and Factory methods
 
@@ -75,6 +76,30 @@ namespace Microsoft.ML.OnnxRuntime
             return options;
         }
 
+        /// <summary>
+        /// A helper method to construct a SessionOptions object for TensorRT execution.
+        /// Use only if CUDA/TensorRT are installed and you have the onnxruntime package specific to this Execution Provider.
+        /// </summary>
+        /// <param name="deviceId"></param>
+        /// <returns>A SessionsOptions() object configured for execution on deviceId</returns>
+        public static SessionOptions MakeSessionOptionWithTensorrtProvider(int deviceId = 0)
+        {
+            CheckTensorrtExecutionProviderDLLs();
+            SessionOptions options = new SessionOptions();
+            try
+            {
+                NativeApiStatus.VerifySuccess(NativeMethods.OrtSessionOptionsAppendExecutionProvider_Tensorrt(options.Handle, deviceId));
+                NativeApiStatus.VerifySuccess(NativeMethods.OrtSessionOptionsAppendExecutionProvider_CUDA(options.Handle, deviceId));
+                NativeApiStatus.VerifySuccess(NativeMethods.OrtSessionOptionsAppendExecutionProvider_CPU(options.Handle, 1));
+                return options;
+            }
+            catch (Exception e)
+            {
+                options.Dispose();
+                throw;
+            }
+        }
+
         /// <summary>
         /// A helper method to construct a SessionOptions object for Nuphar execution.
         /// Use only if you have the onnxruntime package specific to this Execution Provider.
@@ -624,6 +649,27 @@ namespace Microsoft.ML.OnnxRuntime
             return true;
         }
 
+        private static bool CheckTensorrtExecutionProviderDLLs()
+        {
+            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            {
+                foreach (var dll in trtDelayLoadedLibs)
+                {
+                    IntPtr handle = LoadLibrary(dll);
+                    if (handle != IntPtr.Zero)
+                        continue;
+                    var sysdir = new StringBuilder(String.Empty, 2048);
+                    GetSystemDirectory(sysdir, (uint)sysdir.Capacity);
+                    throw new OnnxRuntimeException(
+                        ErrorCode.NoSuchFile,
+                        $"kernel32.LoadLibrary():'{dll}' not found. TensorRT/CUDA are required for GPU execution. " +
+                        $". Verify it is available in the system directory={sysdir}. Else copy it to the output folder."
+                        );
+                }
+            }
+            return true;
+        }
+
 
         #endregion
         #region SafeHandle

csharp/test/Microsoft.ML.OnnxRuntime.Tests/InferenceTest.cs

@@ -227,6 +227,40 @@ namespace Microsoft.ML.OnnxRuntime.Tests
             }
         }
 
+#if USE_TENSORRT
+        [Fact]
+        private void CanRunInferenceOnAModelWithTensorRT()
+        {
+            string modelPath = Path.Combine(Directory.GetCurrentDirectory(), "squeezenet.onnx");
+
+            using (var cleanUp = new DisposableListTest<IDisposable>())
+            {
+                SessionOptions options = SessionOptions.MakeSessionOptionWithTensorrtProvider(0);
+                cleanUp.Add(options);
+
+                var session = new InferenceSession(modelPath, options);
+                cleanUp.Add(session);
+
+                var inputMeta = session.InputMetadata;
+                var container = new List<NamedOnnxValue>();
+                float[] inputData = LoadTensorFromFile(@"bench.in"); // this is the data for only one input tensor for this model
+                foreach (var name in inputMeta.Keys)
+                {
+                    Assert.Equal(typeof(float), inputMeta[name].ElementType);
+                    Assert.True(inputMeta[name].IsTensor);
+                    var tensor = new DenseTensor<float>(inputData, inputMeta[name].Dimensions);
+                    container.Add(NamedOnnxValue.CreateFromTensor<float>(name, tensor));
+                }
+
+
+                using (var results = session.Run(container))
+                {
+                    validateRunResults(results);
+                }
+            }
+        }
+#endif
+
         [Theory]
         [InlineData(GraphOptimizationLevel.ORT_DISABLE_ALL, true)]
         [InlineData(GraphOptimizationLevel.ORT_DISABLE_ALL, false)]