Here is an updated version of the dynamic object wrapper.
public static class DynamicObjectWrapperExtension {
/// <summary>
/// Return provided object as a <seealso cref="System.Dynamic.DynamicObject"/>
/// </summary>
public static dynamic AsDynamicObject(this object value) {
return new DynamicObjectWrapper(value);
}
}
public class DynamicObjectWrapper : DynamicObject, IEquatable<DynamicObjectWrapper> {
private readonly object value;
private readonly Type valueType;
public DynamicObjectWrapper(object value) {
this.value = value;
this.valueType = value.GetType();
}
public override IEnumerable<string> GetDynamicMemberNames() {
return valueType.GetProperties().Select(p => p.Name);
}
public override bool TryConvert(ConvertBinder binder, out object result) {
result = null;
try {
result = changeTypeCore(value, binder.Type);
} catch {
return false;
}
return true;
}
private object changeTypeCore(object value, Type convertionType) {
if (ReferenceEquals(value, null))
return getDefaultValueForType(convertionType);
var providedType = valueType;
if (convertionType.IsAssignableFrom(providedType)) {
return value;
}
try {
var converter = TypeDescriptor.GetConverter(convertionType);
if (converter.CanConvertFrom(providedType)) {
return converter.ConvertFrom(value);
}
converter = TypeDescriptor.GetConverter(providedType);
if (converter.CanConvertTo(providedType)) {
return converter.ConvertTo(value, convertionType);
}
} catch {
return value;
}
try {
return Convert.ChangeType(value, convertionType, System.Globalization.CultureInfo.CurrentCulture);
} catch {
return value;
}
}
private object getDefaultValueForType(Type targetType) {
return targetType.IsClass || targetType.IsInterface ? null : Activator.CreateInstance(targetType);
}
public override bool TryGetIndex(GetIndexBinder binder, object[] indexes, out object result) {
result = null;
//1d collection
if (potentialIndex(indexes)) {
int index = (int)indexes[0];
var list = value as IList;
if (validIndex(index, list)) {
result = checkValue(list[index]);
return true;
}
}
return false;
}
private bool validIndex(int index, IList list) {
return index >= 0 && index < list.Count;
}
private bool potentialIndex(object[] indexes) {
return indexes[0] != null && typeof(int) == indexes[0].GetType() && value is IList;
}
public override bool TryGetMember(GetMemberBinder binder, out object result) {
return TryGetValue(binder.Name, out result);
}
public bool TryGetValue(string propertyName, out object result) {
result = null;
var property = valueType.GetProperty(propertyName);
if (property != null) {
var propertyValue = property.GetValue(value, null);
result = checkValue(propertyValue);
return true;
}
return false;
}
private object checkValue(object value) {
var valueType = value.GetType();
return isAnonymousType(valueType)
? new DynamicObjectWrapper(value)
: value;
}
private bool isAnonymousType(Type type) {
//HACK: temporary hack till a proper function can be implemented
return type.Namespace == null &&
type.IsGenericType &&
type.IsClass &&
type.IsSealed &&
type.IsPublic == false;
}
public override bool TryInvokeMember(InvokeMemberBinder binder, object[] args, out object result) {
try {
result = valueType.InvokeMember(
binder.Name,
BindingFlags.InvokeMethod |
BindingFlags.Public |
BindingFlags.Instance,
null, value, args);
return true;
} catch {
result = null;
return false;
}
}
public override bool Equals(object obj) {
// If parameter is null return false.
if (ReferenceEquals(obj, null)) return false;
// Return true if the fields match:
return this.value == obj || (obj is DynamicObjectWrapper && Equals(obj as DynamicObjectWrapper));
}
public bool Equals(DynamicObjectWrapper other) {
// If parameter is null return false.
if (ReferenceEquals(other, null)) return false;
// Return true if the fields match:
return this.value == other.value;
}
public override int GetHashCode() {
return ToString().GetHashCode();
}
public override string ToString() {
var name = GetType().Name;
return string.Format("{0}[{1}]", name, value);
}
}
Assuming the following controller
public class FooController : Controller {
public IActionResult GetAnonymousObject() {
var jsonResult = new {
id = 1,
name = "Foo",
type = "Bar"
};
return Json(jsonResult);
}
public IActionResult GetAnonymousCollection() {
var jsonResult = Enumerable.Range(1, 20).Select(x => new {
id = x,
name = "Foo" + x,
type = "Bar" + x
}).ToList();
return Json(jsonResult);
}
}
Usage examples
[TestClass]
public class DynamicObjectWrapperTests {
[TestMethod]
public void DynamicObjectResultValue_Member_Should_Exist() {
//Arrange
var controller = new FooController();
//Act
var result = controller.GetAnonymousObject() as JsonResult;
//Assert
dynamic obj = result.Value.AsDynamicObject();
Assert.IsNotNull(obj);
Assert.AreEqual(1, obj.id);
Assert.AreEqual("Foo", obj.name);
Assert.AreEqual(3, obj.name.Length);
Assert.AreEqual("Bar", obj.type);
}
[TestMethod]
public void DynamicObjectResultValue_DynamicCollection() {
//Arrange
var controller = new FooController();
//Act
var result = controller.GetAnonymousCollection() as JsonResult;
//Assert
dynamic jsonCollection = result.Value;
foreach (object value in jsonCollection) {
dynamic json = value.AsDynamicObject();
Assert.IsNotNull(json.id,
"JSON record does not contain \"id\" required property.");
Assert.IsNotNull(json.name,
"JSON record does not contain \"name\" required property.");
Assert.IsNotNull(json.type,
"JSON record does not contain \"type\" required property.");
}
}
[TestMethod]
public void DynamicObjectResultValue_DynamicCollection_Should_Convert_To_IEnumerable() {
//Arrange
var controller = new FooController();
//Act
var result = controller.GetAnonymousCollection() as JsonResult;
dynamic jsonCollection = result.Value.AsDynamicObject();
int count = 0;
foreach (var value in jsonCollection) {
count++;
}
//Assert
Assert.IsTrue(count > 0);
}
[TestMethod]
public void DynamicObjectResultValue_DynamicCollection_Index_at_0_Should_Not_be_Null() {
//Arrange
var controller = new FooController();
//Act
var result = controller.GetAnonymousCollection() as JsonResult;
dynamic jsonCollection = result.Value.AsDynamicObject();
//Assert
Assert.IsNotNull(jsonCollection[0]);
}
[TestMethod]
public void DynamicObjectResultValue_DynamicCollection_Should_Be_Indexable() {
//Arrange
var controller = new FooController();
//Act
var result = controller.GetAnonymousCollection() as JsonResult;
dynamic jsonCollection = result.Value.AsDynamicObject();
//Assert
for (var i = 0; i < jsonCollection.Count; i++) {
var json = jsonCollection[i];
Assert.IsNotNull(json);
Assert.IsNotNull(json.id,
"JSON record does not contain \"id\" required property.");
Assert.IsNotNull(json.name,
"JSON record does not contain \"name\" required property.");
Assert.IsNotNull(json.type,
"JSON record does not contain \"type\" required property.");
}
}
[TestMethod]
public void DynamicObjectResultValue_DynamicCollection_Count_Should_Be_20() {
//Arrange
var controller = new FooController();
//Act
var result = controller.GetAnonymousCollection() as JsonResult;
//Assert
dynamic jsonCollection = result.Value.AsDynamicObject();
Assert.AreEqual(20, jsonCollection.Count);
}
}
