Using Diagram before it is fully loaded about blazor.diagrams HOT 7 CLOSED

Hello and thanks!
The problem here is with GetRelativePoint, which calculates the relative point based on the canvas container. While the canvas didn't render, Container is null, so the calculation isn't possible.
The previous version returned null in that case, but I felt that it doesn't make a lot of sense since you shouldn't be using methods that depend on Container before it's initialized.

Solution: Don't use those methods in OnInitializedAsync. Just set the position to null or something you already know.
Hope this helps!

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I have the same result using OnAfterRenderAsync instead of OnInitializedAsync. How can I be alerted when the container is initialized?

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There is a ContainerChanged event in Diagram. May I know why you need the relative point so soon?

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Upon investigation it seemed that we could eleminate the relative point. It was being called from a function that handled adding custom nodes and custom ports both at initialization and when when using drag/drop mouse interaction. It was not needed when seeding the diagram.

However I'm still encoutering a problem without it:

crit: Microsoft.AspNetCore.Components.WebAssembly.Rendering.WebAssemblyRenderer[100]
Unhandled exception rendering component: Object reference not set to an instance of an object.
System.NullReferenceException: Object reference not set to an instance of an object.
at Blazor.Diagrams.Components.DiagramCanvas.get_LayerStyle()
at Blazor.Diagrams.Components.DiagramCanvas.BuildRenderTree(RenderTreeBuilder __builder)

I'll build a minimal example and see if I can isolate the problem

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Hello, you can find a minimal example here using blazor webassembly:

https://github.com/BjornEngelen/DiagramIssue

Upon opening the page, an error occurs

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Hello, not sure if it's normal but you're not setting a value to Diagram.

Anyway, in 2.0.0, there is no need to specify Name in the cascading value. Please use this: <CascadingValue Value="Diagram">.
Tell me if you have any other issues.

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My bad on not initializing Diagram. I probably messed up my push. But your suggestion of not using Name did actually solve this issue in my full solution.

With Name="Diagram" I see:

crit: Microsoft.AspNetCore.Components.WebAssembly.Rendering.WebAssemblyRenderer[100]
      Unhandled exception rendering component: Object reference not set to an instance of an object.
System.NullReferenceException: Object reference not set to an instance of an object.
   at Blazor.Diagrams.Components.DiagramCanvas.OnInitialized() in C:\Users\bjorn\Desktop\Blazor.Diagrams-master\src\Blazor.Diagrams\Components\DiagramCanvas.razor.cs:line 38
   at Microsoft.AspNetCore.Components.ComponentBase.RunInitAndSetParametersAsync()

Without 'Name' the error is gone. Thanks

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