From e3963158ce6d4b977f52bc6c74951c04b71575ef Mon Sep 17 00:00:00 2001
From: Geek <31265244+1257960069@users.noreply.github.com>
Date: Mon, 16 Jun 2025 21:06:36 +0800
Subject: [PATCH] Fix: This handles the issue where a URL parameter like
 `?age=null` cannot be bound to an `int?` type

Fix: This handles the issue where a URL parameter like `?age=null` cannot be bound to an `int?` type.
This fix ensures that when the frontend sends a URL parameter with `null` value (e.g., `new URLSearchParams({ age: null }).toString()`),
 it correctly binds to a nullable integer (`int?`) instead of causing a binding error.
---
 .../src/ModelBinding/Binders/SimpleTypeModelBinder.cs      | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/Mvc/Mvc.Core/src/ModelBinding/Binders/SimpleTypeModelBinder.cs b/src/Mvc/Mvc.Core/src/ModelBinding/Binders/SimpleTypeModelBinder.cs
index 9f60e2bb7cff..a1517f0b256a 100644
--- a/src/Mvc/Mvc.Core/src/ModelBinding/Binders/SimpleTypeModelBinder.cs
+++ b/src/Mvc/Mvc.Core/src/ModelBinding/Binders/SimpleTypeModelBinder.cs
@@ -74,6 +74,13 @@ public Task BindModelAsync(ModelBindingContext bindingContext)
                 // Other than the StringConverter, converters Trim() the value then throw if the result is empty.
                 model = null;
             }
+            else if (bindingContext.ModelMetadata.IsNullableValueType && value == "null")
+            {
+                // Fix: This handles the issue where a URL parameter like `?age=null` cannot be bound to an `int?` type.
+                // This fix ensures that when the frontend sends a URL parameter with `null` value (e.g., `new URLSearchParams({ age: null }).toString()`),
+                // it correctly binds to a nullable integer (`int?`) instead of causing a binding error.
+                model = null;
+            }
             else
             {
                 model = _typeConverter.ConvertFrom(