Add SkipOutput method on HydroComponent to make it possible to condit…

docs/content/features/events.md

@@ -87,7 +87,9 @@ public class ProductList : HydroComponent
 }
 ```
 
-In this case using a Hydro action might be an overkill, since it will cause an unnecessary additional request and rendering of the component. To avoid that, you can dispatch actions straight from your client code by using `Model.Client.Dispatch`:
+In this case using a Hydro action might be an overkill, since it will cause an unnecessary additional request and
+rendering of the component. To avoid that, you can dispatch actions straight from your client code by using
+`Model.Client.Dispatch`:
 
 ```razor
 <button 
@@ -111,7 +113,25 @@ public class ProductList : HydroComponent
 }
 ```
 
-> **_NOTE:_** When using `[SkipOutput]` any changes to the state won't be persisted.
+You can also use SkipOutput method. It's useful when you want to conditionally skip the output:
+
+```csharp
+// ProductList.cshtml.cs
+
+public class ProductList : HydroComponent
+{
+    public void Save()
+    {
+        if (this.Validate())
+        {
+            SkipOutput();
+            Dispatch(new ProductSaved());
+        }
+    }
+}
+```
+
+> **_NOTE:_** When skipping the output, any changes to the state won't be persisted.
 
 ## Synchronous vs asynchronous
 
@@ -127,7 +147,8 @@ public void Add()
 }
 ```
 
-`Add` triggers the event synchronously, so the button that triggers this action will be disabled until both the action and the event executions are done.
+`Add` triggers the event synchronously, so the button that triggers this action will be disabled until both the action
+and the event executions are done.
 
 Now, let's compare it with the asynchronous way:
 
@@ -139,8 +160,8 @@ public void Add()
 }
 ```
 
-`Add` triggers the event asynchronously, so the button that triggers this action will be disabled until the action is done. The event execution won't be connected with the action's pipeline and will be run on its own.
-
+`Add` triggers the event asynchronously, so the button that triggers this action will be disabled until the action is
+done. The event execution won't be connected with the action's pipeline and will be run on its own.
 
 ## Event scope
 
@@ -204,11 +225,12 @@ There might be a situation where you want to filter the events you receive in yo
 your component subscribes to an event, but handles it only when it contains a certain flag. That flag can be any string
 and is called a `subject`.
 
-You can imagine a page with multiple lists of todos. Each list is a Hydro component that listens to events like `TodoAdded`,
-`TodoRemoved` or `TodoEdited`. When a todo is removed on one list, you don't want all the other lists to receive and react to that event, but only
-the list that contained that todo item. This is solved in Hydro by using `subject` parameter, which in this case will be the list's id.
-When `TodoAdded`, `TodoRemoved` or `TodoEdited` are dispatched, `subject` is set to their list's id. The list component subscribes to those
-events with `subject` set to the their list's id.
+You can imagine a page with multiple lists of todos. Each list is a Hydro component that listens to events like
+`TodoAdded`, `TodoRemoved` or `TodoEdited`. When a todo is removed on one list, you don't want all the other lists to
+receive and react to that event, but only the list that contained that todo item. This is solved in Hydro by using
+`subject` parameter, which in this case will be the list's id. When `TodoAdded`, `TodoRemoved` or `TodoEdited` are
+dispatched, `subject` is set to their list's id. The list component subscribes to those events with `subject` set to the
+their list's id.
 
 Example:
 
@@ -250,9 +272,9 @@ public class TodoList : HydroComponent
 }
 ```
 
-In `Subscribe` method call `subject` parameter is a `Func<string>` instead of `string`, 
+In `Subscribe` method call `subject` parameter is a `Func<string>` instead of `string`,
 because its value could be taken from component's properties that are not set yet, since it's
 a constructor.
 
 > NOTE: If you subscribe for an event without specifying the subject, it will catch all the events
-of that type, no matter if they were dispatched with subject or not.
+> of that type, no matter if they were dispatched with subject or not.

src/HydroComponent.cs

@@ -479,7 +479,7 @@ public void Redirect(string url) =>
     /// <param name="payload">Payload for the destination components</param>
     public void Location(string url, object payload = null) =>
         HttpContext.Response.HydroLocation(url, payload);
-    
+
     /// <summary>
     /// Cache value
     /// </summary>
@@ -511,6 +511,17 @@ protected Cache<T> Cache<T>(Func<T> func, CacheLifetime lifetime = CacheLifetime
         return cacheValue;
     }
 
+    /// <summary>
+    /// Skips generating the HTML output after executing the decorated Hydro action.
+    /// Any changes to the state won't be persisted.
+    /// Useful when action is performing only side effects that do not cause changes to the current component's HTML content.
+    /// </summary>
+    protected void SkipOutput()
+    {
+        _skipOutput = true;
+        HttpContext.Response.Headers.TryAdd(HydroConsts.ResponseHeaders.SkipOutput, "True");
+    }
+
     private async Task<string> RenderOnlineComponent(IPersistentState persistentState) =>
         DetermineRootComponent()
             ? await RenderOnlineRootComponent(persistentState)
@@ -533,7 +544,7 @@ private async Task<string> RenderOnlineRootComponent(IPersistentState persistent
         _componentId = componentId;
 
         PopulateBaseModel(persistentState);
-        
+
         if (!await AuthorizeAsync())
         {
             return string.Empty;
@@ -658,7 +669,7 @@ private async Task<string> GenerateComponentHtml(string componentId, IPersistent
             {
                 AddClientScript($"Hydro.dispatchEvents('{GetSerializedEventDispatchers()}', this);");
             }
-            
+
             foreach (var script in _clientScripts)
             {
                 rootElement.AppendChild(GetClientScript(componentHtmlDocument, script));
@@ -899,8 +910,7 @@ private async Task TriggerMethod()
 
         if (methodAttributes.Any(a => a.GetType() == typeof(SkipOutputAttribute)))
         {
-            _skipOutput = true;
-            HttpContext.Response.Headers.TryAdd(HydroConsts.ResponseHeaders.SkipOutput, "True");
+            SkipOutput();
         }
 
         var operationId = HttpContext.Request.Headers.TryGetValue(HydroConsts.RequestHeaders.OperationId, out var incomingOperationId)