public void DoesNotNotifyDescendantsIfCascadingParameterValuesAreImmutableAndUnchanged()
{
// Arrange
var renderer = new TestRenderer();
var component = new TestComponent(builder =>
{
builder.OpenComponent <CascadingValue <string> >(0);
builder.AddAttribute(1, "Value", "Unchanging value");
builder.AddAttribute(2, RenderTreeBuilder.ChildContent, new RenderFragment(childBuilder =>
{
childBuilder.OpenComponent <CascadingParameterConsumerComponent <string> >(0);
childBuilder.AddAttribute(1, "RegularParameter", "Goodbye");
childBuilder.CloseComponent();
}));
builder.CloseComponent();
});
// Act 1: Initial render
var componentId = renderer.AssignRootComponentId(component);
component.TriggerRender();
var firstBatch = renderer.Batches.Single();
var nestedComponent = FindComponent <CascadingParameterConsumerComponent <string> >(firstBatch, out _);
Assert.Equal(3, firstBatch.DiffsByComponentId.Count); // Root + CascadingValue + nested
Assert.Equal(1, nestedComponent.NumRenders);
// Act/Assert: Re-render the CascadingValue; observe nested component wasn't re-rendered
component.TriggerRender();
// Assert: We did not re-render CascadingParameterConsumerComponent
Assert.Equal(2, renderer.Batches.Count);
var secondBatch = renderer.Batches[1];
Assert.Equal(2, secondBatch.DiffsByComponentId.Count); // Root + CascadingValue, but not nested one
Assert.Equal(1, nestedComponent.NumRenders);
}
public void CanRenderComponentsIfNotGCed()
{
// Arrange
var renderer = new NoOpRenderer();
var didRender = false;
// Act
var component = new TestComponent(builder =>
{
didRender = true;
});
var componentId = renderer.AssignComponentId(component);
// Unlike the preceding test, we still have a reference to the component
// instance on the stack here, so the following should not cause it to
// be collected. Then when we call RenderComponent, there should be no error.
GC.Collect();
GC.WaitForPendingFinalizers();
renderer.RenderNewBatch(componentId);
// Assert
Assert.True(didRender);
}
public void PassesCascadingParametersToNestedComponents()
{
// Arrange
var renderer = new TestRenderer();
var component = new TestComponent(builder =>
{
builder.OpenComponent <CascadingValue <string> >(0);
builder.AddAttribute(1, "Value", "Hello");
builder.AddAttribute(2, RenderTreeBuilder.ChildContent, new RenderFragment(childBuilder =>
{
childBuilder.OpenComponent <CascadingParameterConsumerComponent <string> >(0);
childBuilder.AddAttribute(1, "RegularParameter", "Goodbye");
childBuilder.CloseComponent();
}));
builder.CloseComponent();
});
// Act/Assert
var componentId = renderer.AssignRootComponentId(component);
component.TriggerRender();
var batch = renderer.Batches.Single();
var nestedComponent = FindComponent <CascadingParameterConsumerComponent <string> >(batch, out var nestedComponentId);
var nestedComponentDiff = batch.DiffsByComponentId[nestedComponentId].Single();
// The nested component was rendered with the correct parameters
Assert.Collection(nestedComponentDiff.Edits,
edit =>
{
Assert.Equal(RenderTreeEditType.PrependFrame, edit.Type);
AssertFrame.Text(
batch.ReferenceFrames[edit.ReferenceFrameIndex],
"CascadingParameter=Hello; RegularParameter=Goodbye");
});
Assert.Equal(1, nestedComponent.NumRenders);
}
public void ComponentCanTriggerRenderWhenExistingBatchIsInProgress()
{
// Arrange
var renderer = new TestRenderer();
TestComponent parent = null;
var parentRenderCount = 0;
parent = new TestComponent(builder =>
{
builder.OpenComponent <ReRendersParentComponent>(0);
builder.AddAttribute(1, nameof(ReRendersParentComponent.Parent), parent);
builder.CloseComponent();
builder.AddContent(2, $"Parent render count: {++parentRenderCount}");
});
var parentComponentId = renderer.AssignComponentId(parent);
// Act
parent.TriggerRender();
// Assert
var batch = renderer.Batches.Single();
Assert.Equal(4, batch.DiffsInOrder.Count);
// First is the parent component's initial render
var diff1 = batch.DiffsInOrder[0];
Assert.Equal(parentComponentId, diff1.ComponentId);
Assert.Collection(diff1.Edits,
edit =>
{
Assert.Equal(RenderTreeEditType.PrependFrame, edit.Type);
AssertFrame.Component <ReRendersParentComponent>(
batch.ReferenceFrames[edit.ReferenceFrameIndex]);
},
edit =>
{
Assert.Equal(RenderTreeEditType.PrependFrame, edit.Type);
AssertFrame.Text(
batch.ReferenceFrames[edit.ReferenceFrameIndex],
"Parent render count: 1");
});
// Second is the child component's single render
var diff2 = batch.DiffsInOrder[1];
Assert.NotEqual(parentComponentId, diff2.ComponentId);
var diff2edit = diff2.Edits.Single();
Assert.Equal(RenderTreeEditType.PrependFrame, diff2edit.Type);
AssertFrame.Text(batch.ReferenceFrames[diff2edit.ReferenceFrameIndex],
"Child is here");
// Third is the parent's triggered render
var diff3 = batch.DiffsInOrder[2];
Assert.Equal(parentComponentId, diff3.ComponentId);
var diff3edit = diff3.Edits.Single();
Assert.Equal(RenderTreeEditType.UpdateText, diff3edit.Type);
AssertFrame.Text(batch.ReferenceFrames[diff3edit.ReferenceFrameIndex],
"Parent render count: 2");
// Fourth is child's rerender due to parent rendering
var diff4 = batch.DiffsInOrder[3];
Assert.NotEqual(parentComponentId, diff4.ComponentId);
Assert.Empty(diff4.Edits);
}
public void AllRendersTriggeredSynchronouslyDuringEventHandlerAreHandledAsSingleBatch()
{
// Arrange: A root component with a child whose event handler explicitly queues
// a re-render of both the root component and the child
var renderer = new TestRenderer();
var eventCount = 0;
TestComponent rootComponent = null;
EventComponent childComponent = null;
rootComponent = new TestComponent(builder =>
{
builder.AddContent(0, "Child event count: " + eventCount);
builder.OpenComponent <EventComponent>(1);
builder.AddAttribute(2, nameof(EventComponent.OnTest), args =>
{
eventCount++;
rootComponent.TriggerRender();
childComponent.TriggerRender();
});
builder.CloseComponent();
});
var rootComponentId = renderer.AssignComponentId(rootComponent);
rootComponent.TriggerRender();
var origBatchReferenceFrames = renderer.Batches.Single().ReferenceFrames;
var childComponentFrame = origBatchReferenceFrames
.Single(f => f.Component is EventComponent);
var childComponentId = childComponentFrame.ComponentId;
childComponent = (EventComponent)childComponentFrame.Component;
var origEventHandlerId = origBatchReferenceFrames
.Where(f => f.FrameType == RenderTreeFrameType.Attribute)
.Last(f => f.AttributeEventHandlerId != 0)
.AttributeEventHandlerId;
Assert.Single(renderer.Batches);
// Act
renderer.DispatchEvent(childComponentId, origEventHandlerId, args: null);
// Assert
Assert.Equal(2, renderer.Batches.Count);
var batch = renderer.Batches.Last();
Assert.Collection(batch.DiffsInOrder,
diff =>
{
// First we triggered the root component to re-render
Assert.Equal(rootComponentId, diff.ComponentId);
Assert.Collection(diff.Edits, edit =>
{
Assert.Equal(RenderTreeEditType.UpdateText, edit.Type);
AssertFrame.Text(
batch.ReferenceFrames[edit.ReferenceFrameIndex],
"Child event count: 1");
});
},
diff =>
{
// Then the root re-render will have triggered an update to the child
Assert.Equal(childComponentId, diff.ComponentId);
Assert.Collection(diff.Edits, edit =>
{
Assert.Equal(RenderTreeEditType.UpdateText, edit.Type);
AssertFrame.Text(
batch.ReferenceFrames[edit.ReferenceFrameIndex],
"Render count: 2");
});
},
diff =>
{
// Finally we explicitly requested a re-render of the child
Assert.Equal(childComponentId, diff.ComponentId);
Assert.Collection(diff.Edits, edit =>
{
Assert.Equal(RenderTreeEditType.UpdateText, edit.Type);
AssertFrame.Text(
batch.ReferenceFrames[edit.ReferenceFrameIndex],
"Render count: 3");
});
});
}
public void DoesNotNotifyDescendantsOfUpdatedCascadingParameterValuesWhenFixed()
{
// Arrange
var providedValue = "Initial value";
var shouldIncludeChild = true;
var renderer = new TestRenderer();
var component = new TestComponent(builder =>
{
builder.OpenComponent <CascadingValue <string> >(0);
builder.AddAttribute(1, "Value", providedValue);
builder.AddAttribute(2, "IsFixed", true);
builder.AddAttribute(3, RenderTreeBuilder.ChildContent, new RenderFragment(childBuilder =>
{
if (shouldIncludeChild)
{
childBuilder.OpenComponent <CascadingParameterConsumerComponent <string> >(0);
childBuilder.AddAttribute(1, "RegularParameter", "Goodbye");
childBuilder.CloseComponent();
}
}));
builder.CloseComponent();
});
// Act 1: Initial render; capture nested component ID
var componentId = renderer.AssignRootComponentId(component);
component.TriggerRender();
var firstBatch = renderer.Batches.Single();
var nestedComponent = FindComponent <CascadingParameterConsumerComponent <string> >(firstBatch, out var nestedComponentId);
Assert.Equal(1, nestedComponent.NumRenders);
// Assert: Initial value is supplied to descendant
var nestedComponentDiff = firstBatch.DiffsByComponentId[nestedComponentId].Single();
Assert.Collection(nestedComponentDiff.Edits, edit =>
{
Assert.Equal(RenderTreeEditType.PrependFrame, edit.Type);
AssertFrame.Text(
firstBatch.ReferenceFrames[edit.ReferenceFrameIndex],
"CascadingParameter=Initial value; RegularParameter=Goodbye");
});
// Act 2: Re-render CascadingValue with new value
providedValue = "Updated value";
component.TriggerRender();
// Assert: We did not re-render the descendant
Assert.Equal(2, renderer.Batches.Count);
var secondBatch = renderer.Batches[1];
Assert.Equal(2, secondBatch.DiffsByComponentId.Count); // Root + CascadingValue, but not nested one
Assert.Equal(1, nestedComponent.NumSetParametersCalls);
Assert.Equal(1, nestedComponent.NumRenders);
// Act 3: Dispose
shouldIncludeChild = false;
component.TriggerRender();
// Assert: Absence of an exception here implies we didn't cause a problem by
// trying to remove a non-existent subscription
}