Fix deserialization of DateTime types and allow type coercion between DateTime and DateTimeOffset peroperties (Azure#25804)

* Allow type coercion between DateTime and DateTimeOffset peroperties

Author: christothes

sdk/tables/Azure.Data.Tables/CHANGELOG.md

@@ -7,6 +7,7 @@
 ### Breaking Changes
 
 ### Bugs Fixed
+- Fixed a an issue when using `TableEntity.GetDateTime` that resulted in an `InvalidOperationException` exception. ([#25323](https://github.com/Azure/azure-sdk-for-net/issues/25323)) 
 
 ### Other Changes
 

sdk/tables/Azure.Data.Tables/src/TableEntity.cs

@@ -237,14 +237,19 @@ private object GetValue(string key, Type type = null)
             if (type != null)
             {
                 var valueType = value.GetType();
-                if (type == typeof(BinaryData) && valueType == typeof(byte[]))
+                if (type == typeof(DateTime?) && valueType == typeof(DateTimeOffset))
+                {
+                    return ((DateTimeOffset)value).UtcDateTime;
+                }
+                if (type == typeof(DateTimeOffset?) && valueType == typeof(DateTime))
                 {
-                    value = new BinaryData(value);
+                    return new DateTimeOffset((DateTime)value);
                 }
-                else
+                if (type == typeof(BinaryData) && valueType == typeof(byte[]))
                 {
-                    EnforceType(type, valueType);
+                     return new BinaryData(value);
                 }
+                EnforceType(type, valueType);
             }
 
             return value;

sdk/tables/Azure.Data.Tables/tests/TableEntityTests.cs

@@ -246,5 +246,28 @@ public void TypeCoercionForNumericTypes()
             Assert.That(entity["Foo3"], Is.EqualTo(now));
             Assert.That(entity["Foo3"] is DateTime);
         }
+
+         [Test]
+        public void TypeCoercionForDateTimeTypes()
+        {
+            var entity = new TableEntity("partition", "row");
+            var offsetNow = DateTimeOffset.UtcNow;
+            var dateNow = offsetNow.UtcDateTime;
+
+            // Initialize a property to an DateTimeOffset value
+            entity["DTOffset"] = offsetNow;
+            Assert.That(entity["DTOffset"] is DateTimeOffset);
+            Assert.That(entity["DTOffset"], Is.EqualTo(offsetNow));
+            Assert.That(entity.GetDateTimeOffset("DTOffset"), Is.EqualTo(offsetNow));
+            Assert.That(entity.GetDateTime("DTOffset"), Is.EqualTo(dateNow));
+
+            // Initialize a property to an DateTime value
+            entity["DT"] = dateNow;
+            Assert.AreEqual(typeof(DateTime), entity["DT"].GetType());
+            DateTimeOffset dtoffset = (DateTime)entity["DT"];
+            Assert.That(entity["DT"], Is.EqualTo(dateNow));
+            Assert.That(entity.GetDateTime("DT"), Is.EqualTo(dateNow));
+            Assert.That(entity.GetDateTimeOffset("DT"), Is.EqualTo(offsetNow));
+        }
     }
 }