CodeInput: Focus last box when all boxes are filled

src/CodeBeam.MudBlazor.Extensions/Components/CodeInput/MudCodeInput.razor.cs

@@ -248,7 +248,7 @@ protected async Task CheckFocus(int count)
                 return;
             }
             string str = ConvertSet(_theValue.Value) ?? string.Empty;
-            await _elementReferences[str.Length].FocusAsync();
+            await _elementReferences[Math.Min(str.Length, _count.Value - 1)].FocusAsync();
         }
 
         /// <summary>

tests/CodeBeam.MudBlazor.Extensions.UnitTests/Components/CodeInputTests.cs

@@ -0,0 +1,27 @@
+using Bunit;
+using AwesomeAssertions;
+using Microsoft.AspNetCore.Components;
+
+namespace MudExtensions.UnitTests.Components
+{
+    [TestFixture]
+    public class CodeInputTests : BunitTest
+    {
+        [TestCase("123", 3)]
+        [TestCase("123456", 5)]
+        public async Task CodeInput_Focus_RedirectsToFirstEmptyOrLastBox(string value, int expectedIndex)
+        {
+            var comp = Context.Render<MudCodeInput<string>>(opt =>
+            {
+                opt.Add(a => a.Count, 6);
+                opt.Add(a => a.Value, value);
+            });
+            var fields = comp.FindComponents<MudTextFieldExtended<string>>();
+
+            await comp.FindAll("input")[1].FocusAsync(new());
+
+            var focused = (ElementReference)Context.JSInterop.VerifyFocusAsyncInvoke().Arguments[0]!;
+            focused.Id.Should().Be(fields[expectedIndex].Instance.InputReference.ElementReference.Id);
+        }
+    }
+}