检查SignalR组件是否存在

Question

How can I check if SignalR assembly exists or not to avoid this error:

Could not load file or assembly 'Microsoft.AspNet.SignalR.Core, Version=2.2.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'

I want to run a method when SignalR dll exists. I have this code but it's always false .

var exists = AppDomain.CurrentDomain.GetAssemblies().Any(item => item.FullName.Contains("Microsoft.AspNet.SignalR.Core"));
if (exists)
    AddRowSignalR(faraLog);

what is the best solution?

Answer 1

GetAssemblies for the current domain will only list assemblies that are already loaded in that domain. See the documentation:

https://msdn.microsoft.com/en-us/library/system.appdomain.getassemblies%28v=vs.110%29.aspx

The assembly won't be auto-loaded until a type from that assembly is referenced in executed code. If you want to load an assembly without (first) referencing any types from that assembly in code directly, you need to use the Assembly.Load method. See the documentation, especially the example at the bottom:

https://msdn.microsoft.com/en-us/library/25y1ya39%28v=vs.110%29.aspx