From 8ccaf89a903e8890cbf569856890d5f9debc5b85 Mon Sep 17 00:00:00 2001
From: Regenhardt Marlon <m.regenhardt@softfair.de>
Date: Tue, 19 Dec 2023 18:09:14 +0100
Subject: [PATCH] JSInterop: Enable returning null for a nullable value type

When a result value is null, and the return type is a nullable value type, Convert.ChangeType throws instead of returning the null value.

#30366
---
 .../src/Infrastructure/TaskGenericsUtil.cs                    | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/JSInterop/Microsoft.JSInterop/src/Infrastructure/TaskGenericsUtil.cs b/src/JSInterop/Microsoft.JSInterop/src/Infrastructure/TaskGenericsUtil.cs
index a03d87536db1..ee99390a5d89 100644
--- a/src/JSInterop/Microsoft.JSInterop/src/Infrastructure/TaskGenericsUtil.cs
+++ b/src/JSInterop/Microsoft.JSInterop/src/Infrastructure/TaskGenericsUtil.cs
@@ -89,7 +89,9 @@ public void SetResult(object tcs, object? result)
             // If necessary, attempt a cast
             var typedResult = result is T resultT
                 ? resultT
-                : (T)Convert.ChangeType(result, typeof(T), CultureInfo.InvariantCulture)!;
+                : result == null && default(T) == null
+                    ? default(T)
+                    : (T)Convert.ChangeType(result, typeof(T), CultureInfo.InvariantCulture)!;
 
             typedTcs.SetResult(typedResult!);
         }