Hi,
I’m currently evaluating Aspose.Diagram for .NET and it seems good so far. However, it throws a NullReferenceException when loading some Visio Drawing files in VSDX format. I have attached one such file to this message. I tested with the latest version of Aspose.Diagram at the time of this writing (version 17.9 for .NET Framework 3.5). Try loading the file as follows and you will get the exception:
Diagram = new Diagram("AsposeError.vsdx");
AsposeError.zip (3.5 KB)