Merge pull request #64 from hydrostack/28-add-key-attribute-only-on-d…

…emand

Include key only if present. Include key in the serialized model.

src/HydroComponent.cs

@@ -57,6 +57,7 @@ public abstract class HydroComponent : ViewComponent
     /// <summary>
     /// Provides component's key value
     /// </summary>
+    [JsonProperty]
     protected string Key { get; private set; }
 
     /// <summary>
@@ -130,8 +131,8 @@ private void ConfigurePolls()
     /// <summary>
     /// Implementation of ViewComponent's InvokeAsync method
     /// </summary>
-    /// <param name="parameters">Parameters</param>
-    /// <param name="key">Key</param>
+    /// <param name="parameters">An object with component parameters</param>
+    /// <param name="key">Local identifier to distinguish components of same type</param>
     public async Task<IHtmlContent> InvokeAsync(object parameters = null, string key = null)
     {
         ApplyParameters(parameters);
@@ -424,7 +425,7 @@ private async Task<string> RenderOnlineNestedComponent(IPersistentState persiste
 
         if (IsComponentIdRendered(componentId))
         {
-            return GetComponentPlaceholderTemplate(componentId);
+            return GetComponentPlaceholderTemplate(componentId, Key);
         }
 
         if (!await AuthorizeAsync())
@@ -438,8 +439,8 @@ private async Task<string> RenderOnlineNestedComponent(IPersistentState persiste
         return await GenerateComponentHtml(componentId, persistentState, includeScripts: true);
     }
 
-    private static string GetComponentPlaceholderTemplate(string componentId) =>
-        $"<div id=\"{componentId}\" key=\"{componentId}\" hydro hydro-placeholder></div>";
+    private static string GetComponentPlaceholderTemplate(string componentId, string key) =>
+        $"<div id=\"{componentId}\" {(!string.IsNullOrWhiteSpace(key) ? $"key=\"{key}\"" : "")} hydro hydro-placeholder></div>";
 
     private async Task<string> RenderStaticComponent(IPersistentState persistentState)
     {
@@ -487,9 +488,14 @@ private async Task<string> GenerateComponentHtml(string componentId, IPersistent
         var rootElement = root.ChildNodes.First(n => n.NodeType == HtmlNodeType.Element);
 
         rootElement.SetAttributeValue("id", componentId);
-        rootElement.SetAttributeValue("key", componentId);
         rootElement.SetAttributeValue("hydro-name", GetType().Name);
         rootElement.SetAttributeValue("x-data", "hydro");
+
+        if (!string.IsNullOrWhiteSpace(Key))
+        {
+            rootElement.SetAttributeValue("key", Key);
+        }
+
         var hydroAttribute = rootElement.SetAttributeValue("hydro", null);
         hydroAttribute.QuoteType = AttributeValueQuote.WithoutValue;
 
@@ -1073,4 +1079,4 @@ internal void AddClientScript(string script) =>
 
     private static string Hash(string input) =>
         $"W{Convert.ToHexString(MD5.HashData(Encoding.ASCII.GetBytes(input)))}";
-}
+}

src/PropertyInjector.cs

@@ -30,8 +30,16 @@ private static IEnumerable<PropertyInfo> GetPropertyInfos(Type type)
             return properties;
         }
 
-        var propertyInfos = type.GetProperties(BindingFlags.Instance | BindingFlags.Public)
-            .Where(p => (p.DeclaringType != typeof(ViewComponent)) && p.GetSetMethod()?.IsPublic == true && !p.GetCustomAttributes<TransientAttribute>().Any())
+        var viewComponentType = typeof(ViewComponent);
+        var hydroComponentType = typeof(HydroComponent);
+
+        var propertyInfos = type.GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)
+            .Where(p => (p.Name == "Key" && p.DeclaringType == hydroComponentType)
+                        || (p.DeclaringType != viewComponentType
+                            && p.GetGetMethod()?.IsPublic == true
+                            && p.GetSetMethod()?.IsPublic == true
+                            && !p.GetCustomAttributes<TransientAttribute>().Any())
+            )
             .ToArray();
 
         CachedPropertyInfos.TryAdd(type, propertyInfos);

src/TagHelpers/HydroComponentTagHelper.cs

@@ -94,4 +94,4 @@ public override async Task ProcessAsync(TagHelperContext context, TagHelperOutpu
 
         output.Content.SetHtmlContent(componentHtml);
     }
-}
+}