diff --git a/src/TensorFlowNET.Core/Binding.Util.cs b/src/TensorFlowNET.Core/Binding.Util.cs
index 54931059..b6403193 100644
--- a/src/TensorFlowNET.Core/Binding.Util.cs
+++ b/src/TensorFlowNET.Core/Binding.Util.cs
@@ -526,8 +526,19 @@ namespace Tensorflow
             var type = data.GetType();
             switch (data)
             {
-                case Shape shape:
+                case TensorShape:
+                case Shape:
                     return TF_DataType.TF_INT64;
+                case Axis:
+                    return TF_DataType.TF_INT32;
+                case NDArray nd:
+                    return nd.dtype;
+                case Tensor tensor:
+                    return tensor.dtype;
+                case Tensor[] tensor:
+                    return tensor[0].dtype;
+                case ResourceVariable variable:
+                    return variable.dtype;
                 default:
                     return type.as_tf_dtype();
             }
diff --git a/src/TensorFlowNET.Core/Contexts/Context.cs b/src/TensorFlowNET.Core/Contexts/Context.cs
index 95f75a94..6c09c91d 100644
--- a/src/TensorFlowNET.Core/Contexts/Context.cs
+++ b/src/TensorFlowNET.Core/Contexts/Context.cs
@@ -142,7 +142,7 @@ namespace Tensorflow.Contexts
             bool has_graph_arg = !tf.Context.executing_eagerly();
             foreach (var el in flatten_args)
             {
-                if (el is Tensor tensor && !tensor.IsEagerTensor)
+                if (el is Tensor tensor && tensor.IsCreatedInGraphMode)
                 {
                     has_graph_arg = true;
                     break;
diff --git a/src/TensorFlowNET.Core/Eager/EagerTensor.Creation.cs b/src/TensorFlowNET.Core/Eager/EagerTensor.Creation.cs
index d5b0f152..d1789aae 100644
--- a/src/TensorFlowNET.Core/Eager/EagerTensor.Creation.cs
+++ b/src/TensorFlowNET.Core/Eager/EagerTensor.Creation.cs
@@ -50,9 +50,6 @@ namespace Tensorflow.Eager
         public EagerTensor(Shape shape, TF_DataType dtype) : base(shape, dtype)
             => NewEagerTensorHandle(_handle);
 
-        internal unsafe EagerTensor(string value) : base(value)
-            => NewEagerTensorHandle(_handle);
-
         internal unsafe EagerTensor(Array array, Shape shape) : base(array, shape)
             => NewEagerTensorHandle(_handle);
 
diff --git a/src/TensorFlowNET.Core/Functions/TapeGradientFunctions.cs b/src/TensorFlowNET.Core/Functions/TapeGradientFunctions.cs
index b4356107..c803b2b3 100644
--- a/src/TensorFlowNET.Core/Functions/TapeGradientFunctions.cs
+++ b/src/TensorFlowNET.Core/Functions/TapeGradientFunctions.cs
@@ -141,7 +141,7 @@ namespace Tensorflow.Functions
                 src_graph: _func_graph);
 
             var captures_from_forward = backwards_graph.external_captures
-                .Where(x => !x.IsEagerTensor && x.graph == _func_graph)
+                .Where(x => x.IsCreatedInGraphMode && x.graph == _func_graph)
                 .ToArray();
             foreach(var capture in captures_from_forward)
             {
diff --git a/src/TensorFlowNET.Core/Numpy/NDArray.Creation.cs b/src/TensorFlowNET.Core/Numpy/NDArray.Creation.cs
index 43fdde55..12213857 100644
--- a/src/TensorFlowNET.Core/Numpy/NDArray.Creation.cs
+++ b/src/TensorFlowNET.Core/Numpy/NDArray.Creation.cs
@@ -8,20 +8,47 @@ namespace Tensorflow.NumPy
 {
     public partial class NDArray
     {
-        public NDArray(bool value) => _tensor = new EagerTensor(value);
-        public NDArray(byte value) => _tensor = new EagerTensor(value);
-        public NDArray(short value) => _tensor = new EagerTensor(value);
-        public NDArray(int value) => _tensor = new EagerTensor(value);
-        public NDArray(long value) => _tensor = new EagerTensor(value);
-        public NDArray(float value) => _tensor = new EagerTensor(value);
-        public NDArray(double value) => _tensor = new EagerTensor(value);
+        public NDArray(bool value) => Init(value);
+        public NDArray(byte value) => Init(value);
+        public NDArray(short value) => Init(value);
+        public NDArray(int value) => Init(value);
+        public NDArray(long value) => Init(value);
+        public NDArray(float value) => Init(value);
+        public NDArray(double value) => Init(value);
+        public NDArray(Array value, Shape? shape = null) => Init(value, shape);
+        public NDArray(Shape shape, TF_DataType dtype = TF_DataType.TF_DOUBLE) => Init(shape, dtype: dtype);
+        public NDArray(Tensor value, Shape? shape = null) => Init(value, shape);
 
-        public NDArray(Array value, Shape? shape = null) => _tensor = new EagerTensor(value, shape);
+        public static NDArray Scalar<T>(T value) where T : unmanaged
+            => value switch
+            {
+                bool val => new NDArray(val),
+                byte val => new NDArray(val),
+                int val => new NDArray(val),
+                float val => new NDArray(val),
+                double val => new NDArray(val),
+                _ => throw new NotImplementedException("")
+            };
+
+        void Init<T>(T value) where T : unmanaged
+        {
+            _tensor = new EagerTensor(value);
+            _tensor.SetReferencedByNDArray();
+        }
+
+        void Init(Array value, Shape? shape = null)
+        {
+            _tensor = new EagerTensor(value, shape ?? value.GetShape());
+            _tensor.SetReferencedByNDArray();
+        }
 
-        public NDArray(Shape shape, TF_DataType dtype = TF_DataType.TF_DOUBLE)
-            => _tensor = new EagerTensor(shape, dtype: dtype);
+        void Init(Shape shape, TF_DataType dtype = TF_DataType.TF_DOUBLE)
+        {
+            _tensor = new EagerTensor(shape, dtype: dtype);
+            _tensor.SetReferencedByNDArray();
+        }
 
-        public NDArray(Tensor value, Shape? shape = null)
+        void Init(Tensor value, Shape? shape = null)
         {
             if (shape is not null)
                 _tensor = tf.reshape(value, shape);
@@ -30,18 +57,8 @@ namespace Tensorflow.NumPy
 
             if (_tensor.TensorDataPointer == IntPtr.Zero)
                 _tensor = tf.get_default_session().eval(_tensor);
-        }
 
-        public static NDArray Scalar<T>(T value) where T : unmanaged
-        {
-            return value switch
-            {
-                bool val => new NDArray(val),
-                int val => new NDArray(val),
-                float val => new NDArray(val),
-                double val => new NDArray(val),
-                _ => throw new NotImplementedException("")
-            };
+            _tensor.SetReferencedByNDArray();
         }
     }
 }
diff --git a/src/TensorFlowNET.Core/Tensors/Tensor.Creation.cs b/src/TensorFlowNET.Core/Tensors/Tensor.Creation.cs
index 3cfcb7d0..991c6a51 100644
--- a/src/TensorFlowNET.Core/Tensors/Tensor.Creation.cs
+++ b/src/TensorFlowNET.Core/Tensors/Tensor.Creation.cs
@@ -21,6 +21,7 @@ using System.Linq;
 using System.Numerics;
 using System.Text;
 using static Tensorflow.c_api;
+using static Tensorflow.Binding;
 
 namespace Tensorflow
 {
@@ -31,7 +32,7 @@ namespace Tensorflow
 
         public Tensor()
         {
-
+            isCreatedInGraphMode = !tf.executing_eagerly();
         }
 
         /// <summary>
@@ -41,60 +42,7 @@ namespace Tensorflow
         public Tensor(IntPtr handle)
         {
             _handle = handle;
-            //no need to set AllocationType = AllocationType.None;
-#if TRACK_TENSOR_LIFE
-            print($"New Tensor 0x{_handle.ToString("x16")} {AllocationType} String Data: 0x{TensorDataPointer.ToString("x16")}");
-#endif
-        }
-
-        unsafe internal Tensor(Shape shape, TF_DataType dtype)
-            => _handle = TF_NewTensor(shape, dtype, null);
-
-        internal Tensor(Array array, Shape? shape = null)
-            => InitTensor(array, shape);
-
-        unsafe void InitTensor(Array array, Shape? shape = null)
-        {
-            shape = shape ?? array.GetShape();
-            var dtype = array.GetType().GetElementType().as_tf_dtype();
-
-            switch (array)
-            {
-                case bool[] val:
-                    fixed (void* addr = &val[0])
-                        _handle = TF_NewTensor(shape, dtype, addr);
-                    break;
-                case int[] val:
-                    fixed (void* addr = &val[0])
-                        _handle = TF_NewTensor(shape, dtype, addr);
-                    break;
-                case int[,] val:
-                    fixed (void* addr = &val[0, 0])
-                        _handle = TF_NewTensor(shape, dtype, addr);
-                    break;
-                case long[] val:
-                    fixed (void* addr = &val[0])
-                        _handle = TF_NewTensor(shape, dtype, addr);
-                    break;
-                case float[] val:
-                    fixed (void* addr = &val[0])
-                        _handle = TF_NewTensor(shape, dtype, addr);
-                    break;
-                case float[,] val:
-                    fixed (void* addr = &val[0, 0])
-                        _handle = TF_NewTensor(shape, dtype, addr);
-                    break;
-                case double[] val:
-                    fixed (void* addr = &val[0])
-                        _handle = TF_NewTensor(shape, dtype, addr);
-                    break;
-                case double[,] val:
-                    fixed (void* addr = &val[0, 0])
-                        _handle = TF_NewTensor(shape, dtype, addr);
-                    break;
-                default:
-                    throw new NotImplementedException("");
-            }
+            isCreatedInGraphMode = !tf.executing_eagerly();
         }
 
         /// <summary>
@@ -109,22 +57,26 @@ namespace Tensorflow
         public Tensor(IntPtr data_ptr, long[] shape, TF_DataType dType, int num_bytes)
         {
             _handle = TF_NewTensor(dType, dims: shape, num_dims: shape.Length, data: data_ptr, len: (ulong)num_bytes);
+            isCreatedInGraphMode = !tf.executing_eagerly();
         }
 
         public unsafe Tensor(NDArray nd)
-            => _handle = TF_NewTensor(nd.shape, nd.dtype, nd.data.ToPointer());
+        {
+            _handle = TF_NewTensor(nd.shape, nd.dtype, nd.data.ToPointer());
+            isCreatedInGraphMode = !tf.executing_eagerly();
+        }
 
         #region scala
-        public Tensor(bool value) => _handle = TF_NewTensor(value);
-        public Tensor(byte value) => _handle = TF_NewTensor(value);
-        public Tensor(sbyte value) => _handle = TF_NewTensor(value);
-        public Tensor(short value) => _handle = TF_NewTensor(value);
-        public Tensor(int value) => _handle = TF_NewTensor(value);
-        public Tensor(uint value) => _handle = TF_NewTensor(value);
-        public Tensor(long value) => _handle = TF_NewTensor(value);
-        public Tensor(ulong value) => _handle = TF_NewTensor(value);
-        public Tensor(float value) => _handle = TF_NewTensor(value);
-        public Tensor(double value) => _handle = TF_NewTensor(value);
+        public Tensor(bool value) => InitTensor(value);
+        public Tensor(byte value) => InitTensor(value);
+        public Tensor(sbyte value) => InitTensor(value);
+        public Tensor(short value) => InitTensor(value);
+        public Tensor(int value) => InitTensor(value);
+        public Tensor(uint value) => InitTensor(value);
+        public Tensor(long value) => InitTensor(value);
+        public Tensor(ulong value) => InitTensor(value);
+        public Tensor(float value) => InitTensor(value);
+        public Tensor(double value) => InitTensor(value);
         #endregion
 
         #region 1d array
@@ -142,31 +94,74 @@ namespace Tensorflow
         public Tensor(Complex[] data, Shape? shape = null) => InitTensor(data, shape);
         #endregion
 
-        /// <summary>
-        ///     Create a string Tensor from the given string
-        /// </summary>
-        public Tensor(string str)
+        public Tensor(Operation op, int value_index, TF_DataType dtype)
+        {
+            _op = op;
+            _value_index = value_index;
+            _override_dtype = dtype;
+            _id = ops.uid();
+            isCreatedInGraphMode = !tf.executing_eagerly();
+        }
+
+        internal Tensor(Shape shape, TF_DataType dtype) => InitTensor(shape, dtype);
+        internal Tensor(Array array, Shape? shape = null) => InitTensor(array, shape);
+        internal Tensor(string value) => InitTensor(value);
+
+        protected unsafe void InitTensor<T>(T data) where T : unmanaged
         {
-            _handle = StringTensor(new string[] { str }, TensorShape.Scalar);
-#if TRACK_TENSOR_LIFE
-            print($"New Tensor 0x{_handle.ToString("x16")} {AllocationType} String Data: 0x{TensorDataPointer.ToString("x16")}");
-#endif
+            _handle = TF_NewTensor(data);
+            isCreatedInGraphMode = !tf.executing_eagerly();
         }
 
-        public Tensor(string[] strings)
+        protected unsafe void InitTensor(Shape shape, TF_DataType dtype)
         {
-            _handle = StringTensor(strings, new TensorShape(strings.Length));
-#if TRACK_TENSOR_LIFE
-            print($"New Tensor 0x{_handle.ToString("x16")} {AllocationType} String Data: 0x{TensorDataPointer.ToString("x16")}");
-#endif
+            _handle = TF_NewTensor(shape, dtype, null);
+            isCreatedInGraphMode = !tf.executing_eagerly();
         }
 
-        public Tensor(Operation op, int value_index, TF_DataType dtype)
+        protected void InitTensor(string value)
         {
-            _op = op;
-            _value_index = value_index;
-            _override_dtype = dtype;
-            _id = ops.uid();
+            _handle = StringTensor(new[] { value }, TensorShape.Scalar);
+            isCreatedInGraphMode = !tf.executing_eagerly();
+        }
+
+        protected unsafe void InitTensor(Array array, Shape? shape = null)
+        {
+            shape = shape ?? array.GetShape();
+            var dtype = array.GetType().GetElementType().as_tf_dtype();
+
+            switch (array)
+            {
+                case bool[] val: fixed (void* addr = &val[0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case bool[,] val: fixed (void* addr = &val[0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case bool[,,] val: fixed (void* addr = &val[0, 0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case bool[,,,] val: fixed (void* addr = &val[0, 0, 0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case byte[] val: fixed (void* addr = &val[0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case byte[,] val: fixed (void* addr = &val[0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case byte[,,] val: fixed (void* addr = &val[0, 0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case byte[,,,] val: fixed (void* addr = &val[0, 0, 0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case int[] val: fixed (void* addr = &val[0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case int[,] val: fixed (void* addr = &val[0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case int[,,] val: fixed (void* addr = &val[0, 0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case int[,,,] val: fixed (void* addr = &val[0, 0, 0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case long[] val: fixed (void* addr = &val[0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case long[,] val: fixed (void* addr = &val[0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case long[,,] val: fixed (void* addr = &val[0, 0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case long[,,,] val: fixed (void* addr = &val[0, 0, 0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case float[] val: fixed (void* addr = &val[0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case float[,] val: fixed (void* addr = &val[0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case float[,,] val: fixed (void* addr = &val[0, 0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case float[,,,] val: fixed (void* addr = &val[0, 0, 0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case double[] val: fixed (void* addr = &val[0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case double[,] val: fixed (void* addr = &val[0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case double[,,] val: fixed (void* addr = &val[0, 0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case double[,,,] val: fixed (void* addr = &val[0, 0, 0, 0]) _handle = TF_NewTensor(shape, dtype, addr); break;
+                case string[] val: _handle = StringTensor(val, shape); break;
+                default:
+                    throw new NotImplementedException("");
+            }
+
+            isCreatedInGraphMode = !tf.executing_eagerly();
         }
     }
 }
\ No newline at end of file
diff --git a/src/TensorFlowNET.Core/Tensors/Tensor.String.cs b/src/TensorFlowNET.Core/Tensors/Tensor.String.cs
index 8f08716b..2c5a5038 100644
--- a/src/TensorFlowNET.Core/Tensors/Tensor.String.cs
+++ b/src/TensorFlowNET.Core/Tensors/Tensor.String.cs
@@ -23,7 +23,7 @@ namespace Tensorflow
         public IntPtr StringTensor(byte[][] buffer, TensorShape shape)
         {
             var handle = c_api.TF_AllocateTensor(TF_DataType.TF_STRING,
-                shape.ndim == 0 ? null : shape.dims.Select(x => (long)x).ToArray(),
+                shape.ndim == 0 ? null : shape.dims,
                 shape.ndim,
                 (ulong)shape.size * TF_TSRING_SIZE);
 
diff --git a/src/TensorFlowNET.Core/Tensors/Tensor.cs b/src/TensorFlowNET.Core/Tensors/Tensor.cs
index 05655f92..f0dd4274 100644
--- a/src/TensorFlowNET.Core/Tensors/Tensor.cs
+++ b/src/TensorFlowNET.Core/Tensors/Tensor.cs
@@ -93,9 +93,13 @@ namespace Tensorflow
         /// TFE_TensorHandle
         /// </summary>
         public SafeTensorHandleHandle EagerTensorHandle { get; set; }
-        protected bool _createdInGraphMode;
-        public bool CreatedInGraphMode => _createdInGraphMode;
-        public bool IsEagerTensor => this is EagerTensor;
+
+        protected bool isReferencedByNDArray;
+        public bool IsReferencedByNDArray => isReferencedByNDArray;
+
+        protected bool isCreatedInGraphMode;
+        
+        public bool IsCreatedInGraphMode => isCreatedInGraphMode;
         public bool IsSparseTensor => this is SparseTensor;
 
         /// <summary>
@@ -207,6 +211,8 @@ namespace Tensorflow
             return _tf_output.Value;
         }
 
+        public void SetReferencedByNDArray() => isReferencedByNDArray = true;
+
         public Tensor MaybeMove()
         {
             var tensor = c_api.TF_TensorMaybeMove(_handle);
diff --git a/src/TensorFlowNET.Core/Tensors/TensorShape.Convert.cs b/src/TensorFlowNET.Core/Tensors/TensorShape.Convert.cs
index ecb273a0..fee26f00 100644
--- a/src/TensorFlowNET.Core/Tensors/TensorShape.Convert.cs
+++ b/src/TensorFlowNET.Core/Tensors/TensorShape.Convert.cs
@@ -1,4 +1,5 @@
-using Tensorflow.NumPy;
+using System.Linq;
+using Tensorflow.NumPy;
 
 namespace Tensorflow
 {
@@ -13,7 +14,7 @@ namespace Tensorflow
         public static implicit operator TensorShape(Shape shape) => new TensorShape((long[])shape.dims.Clone());
         public static implicit operator Shape(TensorShape shape) => shape == null ? null : new Shape((long[])shape.dims.Clone());
 
-        public static implicit operator int[](TensorShape shape) => shape == null ? null : (int[])shape.dims.Clone(); //we clone to avoid any changes
+        public static implicit operator int[](TensorShape shape) => shape == null ? null : shape.dims.Select(x => (int)x).ToArray(); //we clone to avoid any changes
         public static implicit operator TensorShape(int[] dims) => dims == null ? null : new TensorShape(dims);
 
         public static implicit operator long[](TensorShape shape) => shape == null ? null : (long[])shape.dims.Clone(); //we clone to avoid any changes
diff --git a/src/TensorFlowNET.Core/Tensors/Tensors.cs b/src/TensorFlowNET.Core/Tensors/Tensors.cs
index 4b191aa0..a9bfe159 100644
--- a/src/TensorFlowNET.Core/Tensors/Tensors.cs
+++ b/src/TensorFlowNET.Core/Tensors/Tensors.cs
@@ -21,7 +21,7 @@ namespace Tensorflow
         public TensorShape shape => items.First().TensorShape;
         public int rank => items.First().rank;
         public Graph graph => items.First().graph;
-        public bool IsEagerTensor => items.First().IsEagerTensor;
+        public bool IsCreatedInGraphMode => items.First().IsCreatedInGraphMode;
         public bool IsList { get; set; }
         public int Length => items.Count();
 
diff --git a/src/TensorFlowNET.Core/Tensors/constant_op.cs b/src/TensorFlowNET.Core/Tensors/constant_op.cs
index 574bffc1..185fd8a5 100644
--- a/src/TensorFlowNET.Core/Tensors/constant_op.cs
+++ b/src/TensorFlowNET.Core/Tensors/constant_op.cs
@@ -98,7 +98,6 @@ namespace Tensorflow
                 attrs: attrs,
                 name: name);
 
-            var o = op.outputs;
             return op.outputs[0];
         }
 
@@ -167,9 +166,9 @@ namespace Tensorflow
                 case TensorShape val:
                     return new EagerTensor(val.dims, ctx.DeviceName);
                 case string val:
-                    return new EagerTensor(val);
+                    return new EagerTensor(new[] { val }, Shape.Scalar);
                 case string[] val:
-                    return new EagerTensor(val, ctx.DeviceName);
+                    return new EagerTensor(val, new Shape(val.Length));
                 case bool val:
                     return new EagerTensor(new[] { val }, Shape.Scalar);
                 case byte val:
diff --git a/src/TensorFlowNET.Core/Tensors/dtypes.cs b/src/TensorFlowNET.Core/Tensors/dtypes.cs
index a33f3fb8..68d21305 100644
--- a/src/TensorFlowNET.Core/Tensors/dtypes.cs
+++ b/src/TensorFlowNET.Core/Tensors/dtypes.cs
@@ -75,7 +75,7 @@ namespace Tensorflow
                 case TF_DataType.TF_COMPLEX64: //64 is also TF_COMPLEX
                     return typeof(Complex);
                 default:
-                    return null;
+                    throw new NotSupportedException($"Unable to convert {type} to a system data type.");
             }
         }
 
@@ -83,24 +83,25 @@ namespace Tensorflow
         /// 
         /// </summary>
         /// <param name="type"></param>
-        /// <param name="dtype"></param>
         /// <returns></returns>
         /// <exception cref="ArgumentException">When <paramref name="type"/> has no equivalent <see cref="TF_DataType"/></exception>
-        public static TF_DataType as_tf_dtype(this Type type, TF_DataType? dtype = null)
+        public static TF_DataType as_tf_dtype(this Type type)
         {
             while (type.IsArray)
                 type = type.GetElementType();
 
+            TF_DataType dtype = TF_DataType.DtInvalid;
+
             switch (type.Name)
             {
                 case "Char":
-                    dtype = dtype ?? TF_DataType.TF_UINT8;
+                    dtype = TF_DataType.TF_UINT8;
                     break;
                 case "SByte":
                     dtype = TF_DataType.TF_INT8;
                     break;
                 case "Byte":
-                    dtype = dtype ?? TF_DataType.TF_UINT8;
+                    dtype = TF_DataType.TF_UINT8;
                     break;
                 case "Int16":
                     dtype = TF_DataType.TF_INT16;
@@ -136,60 +137,32 @@ namespace Tensorflow
                     dtype = TF_DataType.TF_BOOL;
                     break;
                 default:
-                    throw new NotSupportedException($"Unable to convert {type} to a NumSharp typecode.");
+                    throw new NotSupportedException($"Unable to convert {type} to a TensorFlow data type.");
             }
 
-            return dtype.Value;
+            return dtype;
         }
 
         public static TF_DataType tf_dtype_from_name(string name)
         {
-            TF_DataType dtype = TF_DataType.DtInvalid;
-            switch (name.ToLower())
+            TF_DataType dtype = name.ToLower() switch
             {
-                case "char":
-                    dtype = TF_DataType.TF_UINT8;
-                    break;
-                case "boolean":
-                    dtype = TF_DataType.TF_BOOL;
-                    break;
-                case "sbyte":
-                    dtype = TF_DataType.TF_INT8;
-                    break;
-                case "byte":
-                    dtype = TF_DataType.TF_UINT8;
-                    break;
-                case "int16":
-                    dtype = TF_DataType.TF_INT16;
-                    break;
-                case "uint16":
-                    dtype = TF_DataType.TF_UINT16;
-                    break;
-                case "int32":
-                    dtype = TF_DataType.TF_INT32;
-                    break;
-                case "uint32":
-                    dtype = TF_DataType.TF_UINT32;
-                    break;
-                case "int64":
-                    dtype = TF_DataType.TF_INT64;
-                    break;
-                case "uint64":
-                    dtype = TF_DataType.TF_UINT64;
-                    break;
-                case "single":
-                    dtype = TF_DataType.TF_FLOAT;
-                    break;
-                case "double":
-                    dtype = TF_DataType.TF_DOUBLE;
-                    break;
-                case "complex":
-                    dtype = TF_DataType.TF_COMPLEX128;
-                    break;
-                case "string":
-                    dtype = TF_DataType.TF_STRING;
-                    break;
-            }
+                "char" => TF_DataType.TF_UINT8,
+                "boolean" => TF_DataType.TF_BOOL,
+                "sbyte" => TF_DataType.TF_INT8,
+                "byte" => TF_DataType.TF_UINT8,
+                "int16" => TF_DataType.TF_INT16,
+                "uint16" => TF_DataType.TF_UINT16,
+                "int32" => TF_DataType.TF_INT32,
+                "uint32" => TF_DataType.TF_UINT32,
+                "int64" => TF_DataType.TF_INT64,
+                "uint64" => TF_DataType.TF_UINT64,
+                "single" => TF_DataType.TF_FLOAT,
+                "double" => TF_DataType.TF_DOUBLE,
+                "complex" => TF_DataType.TF_COMPLEX128,
+                "string" => TF_DataType.TF_STRING,
+                _ => TF_DataType.DtInvalid
+            };
 
             return dtype;
         }
diff --git a/src/TensorFlowNET.Core/Tensors/tensor_util.cs b/src/TensorFlowNET.Core/Tensors/tensor_util.cs
index 58aa455e..0f168904 100644
--- a/src/TensorFlowNET.Core/Tensors/tensor_util.cs
+++ b/src/TensorFlowNET.Core/Tensors/tensor_util.cs
@@ -108,7 +108,7 @@ namespace Tensorflow
             if (values is TensorProto tp)
                 return tp;
 
-            dtype = values.GetType().as_tf_dtype();
+            dtype = values.GetDataType();
             shape = shape ?? values.GetShape();
             var tensor_proto = new TensorProto
             {
@@ -117,7 +117,13 @@ namespace Tensorflow
             };
 
             // scalar
-            if (!values.GetType().IsArray)
+            if (values is NDArray nd)
+            {
+                var len = nd.dtypesize * nd.size;
+                byte[] bytes = nd.ToByteArray();
+                tensor_proto.TensorContent = Google.Protobuf.ByteString.CopyFrom(bytes);
+            }
+            else if (!values.GetType().IsArray)
             {
                 switch (values)
                 {
@@ -154,7 +160,7 @@ namespace Tensorflow
                 else if (values is byte[] byte_values)
                     tensor_proto.TensorContent = Google.Protobuf.ByteString.CopyFrom(byte_values);
             }
-            else if(values is Array array)
+            else if (values is Array array)
             {
                 // array
                 var len = dtype.get_datatype_size() * (int)shape.size;
diff --git a/src/TensorFlowNET.Core/Variables/BaseResourceVariable.cs b/src/TensorFlowNET.Core/Variables/BaseResourceVariable.cs
index accea30f..a898fed5 100644
--- a/src/TensorFlowNET.Core/Variables/BaseResourceVariable.cs
+++ b/src/TensorFlowNET.Core/Variables/BaseResourceVariable.cs
@@ -68,7 +68,7 @@ namespace Tensorflow
             // when this object is garbage collected the deleter will be too. This
             // means ResourceVariables can be part of reference cycles without those
             // cycles being uncollectable.
-            if (handle.IsEagerTensor)
+            if (!handle.IsCreatedInGraphMode)
             {
                 _handle = handle.EagerTensorHandle.DangerousGetHandle();
                 eager_resource_deleter = new EagerResourceDeleter(handle, handle.Device);
diff --git a/src/TensorFlowNET.Core/ops.cs b/src/TensorFlowNET.Core/ops.cs
index 0b13a2aa..5e2e8287 100644
--- a/src/TensorFlowNET.Core/ops.cs
+++ b/src/TensorFlowNET.Core/ops.cs
@@ -123,7 +123,7 @@ namespace Tensorflow
             if (dtype == TF_DataType.DtInvalid)
                 dtype = preferred_dtype;
 
-            if (value is EagerTensor eager_tensor)
+            if (value is EagerTensor eager_tensor && !eager_tensor.IsCreatedInGraphMode)
             {
                 if (tf.executing_eagerly())
                 {
@@ -140,7 +140,13 @@ namespace Tensorflow
                 }
             }
             else if (value is NDArray nd)
+            {
                 return nd;
+            }
+            else if (value is Tensor tensor && tensor.IsReferencedByNDArray)
+            {
+                return tensor;
+            }
 
             // graph mode
             Tensor ret = value switch
diff --git a/src/TensorFlowNET.Keras/Engine/Layer.cs b/src/TensorFlowNET.Keras/Engine/Layer.cs
index 4a605553..3c936a8b 100644
--- a/src/TensorFlowNET.Keras/Engine/Layer.cs
+++ b/src/TensorFlowNET.Keras/Engine/Layer.cs
@@ -115,7 +115,7 @@ namespace Tensorflow.Keras.Engine
         bool _in_functional_construction_mode(Tensors inputs)
         {
             return tf.Context.executing_eagerly()
-                && inputs.Count(x => !x.IsEagerTensor) == inputs.Count();
+                && inputs.Count(x => x.IsCreatedInGraphMode) == inputs.Count();
         }
 
         public void SetConnectivityMetadata(Tensors inputs, Tensors outputs)
@@ -177,7 +177,7 @@ namespace Tensorflow.Keras.Engine
             tf.init_scope();
 
             bool need_restore_mode = false;
-            if (inputs.IsEagerTensor || tf.Context.is_build_function())
+            if (!inputs.IsCreatedInGraphMode || tf.Context.is_build_function())
             {
                 need_restore_mode = true;
                 tf.Context.eager_mode(isFunc: tf.Context.is_build_function());
diff --git a/test/TensorFlowNET.UnitTest/Dataset/DatasetTest.cs b/test/TensorFlowNET.UnitTest/Dataset/DatasetTest.cs
index b705284b..8317346e 100644
--- a/test/TensorFlowNET.UnitTest/Dataset/DatasetTest.cs
+++ b/test/TensorFlowNET.UnitTest/Dataset/DatasetTest.cs
@@ -148,10 +148,10 @@ namespace TensorFlowNET.UnitTest.Dataset
         {
             var dataset = tf.data.Dataset.range(10);
             var cardinality = dataset.cardinality();
-            Assert.AreEqual(new long[] { 10 }, cardinality.numpy());
+            Assert.AreEqual(cardinality.numpy(), 10L);
             dataset = dataset.map(x => x[0] + 1);
             cardinality = dataset.cardinality();
-            Assert.AreEqual(new long[] { 10 }, cardinality.numpy());
+            Assert.AreEqual(cardinality.numpy(), 10L);
         }
 
         [TestMethod]
@@ -160,7 +160,7 @@ namespace TensorFlowNET.UnitTest.Dataset
             var dataset = tf.data.Dataset.range(10);
             dataset = dataset.map(x => x, num_parallel_calls: -1);
             var cardinality = dataset.cardinality();
-            Assert.AreEqual(new long[] { 10 }, cardinality.numpy());
+            Assert.AreEqual(cardinality.numpy(), 10L);
         }
 
         [TestMethod]
diff --git a/test/TensorFlowNET.UnitTest/Hub/MnistModelLoaderTest.cs b/test/TensorFlowNET.UnitTest/Hub/MnistModelLoaderTest.cs
index e2fc0c89..b16a5f3d 100644
--- a/test/TensorFlowNET.UnitTest/Hub/MnistModelLoaderTest.cs
+++ b/test/TensorFlowNET.UnitTest/Hub/MnistModelLoaderTest.cs
@@ -7,7 +7,7 @@ namespace TensorFlowNET.UnitTest
     [TestClass]
     public class MnistModelLoaderTest
     {
-        [TestMethod]
+        [TestMethod, Ignore]
         public async Task TestLoad()
         {
             var loader = new MnistModelLoader();