Projektdateien hinzufügen.

Controllers/ErrorController.cs

@@ -0,0 +1,21 @@
+using Microsoft.AspNetCore.Mvc;
+
+namespace WebEMSim.Controllers
+{
+    [ApiController]
+    [Route("error")]
+    public class ErrorController : ControllerBase
+    {
+        [HttpGet("{statusCode}", Name = "HandleError")]
+        public IActionResult Handle(int statusCode)
+        {
+            if (statusCode == 404)
+            {
+                var fallbackFile = Path.Combine(Environment.CurrentDirectory, "webem-ui/build/404.html");
+                return PhysicalFile(fallbackFile, "text/html");
+            }
+
+            return StatusCode(statusCode);
+        }
+    }
+}