Fix blazor detection (CopyText#203)

Author: SimonCropp

src/BlazorSample/Program.cs

@@ -18,6 +18,7 @@ public static Task Main()
         #endregion
         builder.RootComponents.Add<App>("app");
         #endregion
+
         serviceCollection.AddTransient(
             provider => new HttpClient
             {

src/TextCopy/ClipboardService.cs

@@ -35,7 +35,7 @@ public static partial class ClipboardService
         static ClipboardService()
         {
 #if NETSTANDARD2_1
-            if (RuntimeInformation.IsOSPlatform(OSPlatform.Create("WEBASSEMBLY")))
+            if (RuntimeInformation.OSDescription == "web")
             {
                 throw new Exception($"The static class ClipboardService is not supported on Blazor. Instead inject an {nameof(IClipboard)} using {nameof(ServiceExtensions)}{nameof(ServiceExtensions.InjectClipboard)}.");
             }

src/TextCopy/ServiceExtensions.cs

@@ -1,4 +1,6 @@
 #if !UAP
+using System;
+using System.Runtime.InteropServices;
 using Microsoft.Extensions.DependencyInjection;
 
 namespace TextCopy
@@ -29,17 +31,20 @@ public static void InjectClipboard(this IServiceCollection services)
             {
 
 #if NETSTANDARD2_1
-
-                var jsRuntimeType = System.Type.GetType("Microsoft.JSInterop.IJSRuntime, Microsoft.JSInterop", false);
-                if (jsRuntimeType != null)
+                if (RuntimeInformation.OSDescription == "web")
                 {
+                    var jsRuntimeType = System.Type.GetType("Microsoft.JSInterop.IJSRuntime, Microsoft.JSInterop", false);
+                    if (jsRuntimeType == null)
+                    {
+                        throw new Exception("Running in Blazor but could not resolve JSInterop type.");
+                    }
                     var jsRuntime = provider.GetService(jsRuntimeType);
-                    if (jsRuntime != null)
+                    if (jsRuntime == null)
                     {
-                        return new BlazorClipboard(jsRuntime);
+                        throw new Exception("Running in Blazor but could not get the JSInterop instance from the IServiceProvider.");
                     }
+                    return new BlazorClipboard(jsRuntime);
                 }
-
 #endif
 
                 return new Clipboard();