Add DropdownValueResolver

Author: vanifatovvlad

Editor.Extras/Drawers/DropdownDrawer.cs

@@ -1,6 +1,4 @@
-using System.Collections.Generic;
-using System.Linq;
-using TriInspector;
+using TriInspector;
 using TriInspector.Drawers;
 using TriInspector.Elements;
 using TriInspector.Resolvers;
@@ -11,53 +9,23 @@ namespace TriInspector.Drawers
 {
     public class DropdownDrawer<T> : TriAttributeDrawer<DropdownAttribute>
     {
-        private ValueResolver<IEnumerable<TriDropdownItem<T>>> _itemsResolver;
-        private ValueResolver<IEnumerable<T>> _valuesResolver;
+        private DropdownValuesResolver<T> _valuesResolver;
 
         public override TriExtensionInitializationResult Initialize(TriPropertyDefinition propertyDefinition)
         {
-            _valuesResolver = ValueResolver.Resolve<IEnumerable<T>>(propertyDefinition, Attribute.Values);
+            _valuesResolver = DropdownValuesResolver<T>.Resolve(propertyDefinition, Attribute.Values);
 
-            if (_valuesResolver.TryGetErrorString(out _))
+            if (_valuesResolver.TryGetErrorString(out var error))
             {
-                _itemsResolver =
-                    ValueResolver.Resolve<IEnumerable<TriDropdownItem<T>>>(propertyDefinition, Attribute.Values);
-
-                if (_itemsResolver.TryGetErrorString(out var itemResolverError))
-                {
-                    return itemResolverError;
-                }
+                return error;
             }
 
             return TriExtensionInitializationResult.Ok;
         }
 
         public override TriElement CreateElement(TriProperty property, TriElement next)
         {
-            return new TriDropdownElement(property, GetDropdownItems);
-        }
-
-        private IEnumerable<ITriDropdownItem> GetDropdownItems(TriProperty property)
-        {
-            if (_valuesResolver != null)
-            {
-                var values = _valuesResolver.GetValue(property, Enumerable.Empty<T>());
-
-                foreach (var value in values)
-                {
-                    yield return new TriDropdownItem {Text = $"{value}", Value = value,};
-                }
-            }
-
-            if (_itemsResolver != null)
-            {
-                var values = _itemsResolver.GetValue(property, Enumerable.Empty<TriDropdownItem<T>>());
-
-                foreach (var value in values)
-                {
-                    yield return value;
-                }
-            }
+            return new TriDropdownElement(property, _valuesResolver.GetDropdownItems);
         }
     }
 }

Editor/Resolvers/DropdownValuesResolver.cs

@@ -0,0 +1,62 @@
+using System.Collections.Generic;
+using System.Linq;
+using JetBrains.Annotations;
+
+namespace TriInspector.Resolvers
+{
+    public class DropdownValuesResolver<T>
+    {
+        [CanBeNull] private ValueResolver<IEnumerable<TriDropdownItem<T>>> _itemsResolver;
+        [CanBeNull] private ValueResolver<IEnumerable<T>> _valuesResolver;
+
+        [PublicAPI]
+        public static DropdownValuesResolver<T> Resolve(TriPropertyDefinition propertyDefinition, string expression)
+        {
+            var valuesResolver = ValueResolver.Resolve<IEnumerable<T>>(propertyDefinition, expression);
+            if (!valuesResolver.TryGetErrorString(out _))
+            {
+                return new DropdownValuesResolver<T>
+                {
+                    _valuesResolver = valuesResolver,
+                };
+            }
+
+            var itemsResolver = ValueResolver.Resolve<IEnumerable<TriDropdownItem<T>>>(propertyDefinition, expression);
+
+            return new DropdownValuesResolver<T>
+            {
+                _itemsResolver = itemsResolver,
+            };
+        }
+
+        [PublicAPI]
+        public bool TryGetErrorString(out string error)
+        {
+            return ValueResolver.TryGetErrorString(_valuesResolver, _itemsResolver, out error);
+        }
+
+        [PublicAPI]
+        public IEnumerable<ITriDropdownItem> GetDropdownItems(TriProperty property)
+        {
+            if (_valuesResolver != null)
+            {
+                var values = _valuesResolver.GetValue(property, Enumerable.Empty<T>());
+
+                foreach (var value in values)
+                {
+                    yield return new TriDropdownItem {Text = $"{value}", Value = value,};
+                }
+            }
+
+            if (_itemsResolver != null)
+            {
+                var values = _itemsResolver.GetValue(property, Enumerable.Empty<TriDropdownItem<T>>());
+
+                foreach (var value in values)
+                {
+                    yield return value;
+                }
+            }
+        }
+    }
+}