Fix MVC form data binding localization

src/Mvc/Mvc.Core/src/Infrastructure/MvcCoreMvcOptionsSetup.cs

@@ -93,7 +93,7 @@ public void Configure(MvcOptions options)
         options.OutputFormatters.Add(jsonOutputFormatter);
 
         // Set up ValueProviders
-        options.ValueProviderFactories.Add(new FormValueProviderFactory());
+        options.ValueProviderFactories.Add(new FormValueProviderFactory(options));
         options.ValueProviderFactories.Add(new RouteValueProviderFactory());
         options.ValueProviderFactories.Add(new QueryStringValueProviderFactory());
         options.ValueProviderFactories.Add(new JQueryFormValueProviderFactory());

src/Mvc/Mvc.Core/src/ModelBinding/FormModelBindingHelper.cs

@@ -0,0 +1,12 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.AspNetCore.Mvc.ModelBinding;
+
+internal static class FormModelBindingHelper
+{
+    public const string CultureInvariantFieldName = "__Invariant";
+
+    public static bool InputTypeUsesCultureInvariantFormatting(string? inputType)
+        => inputType is "number" or "range";
+}

src/Mvc/Mvc.Core/src/ModelBinding/FormValueProvider.cs

@@ -14,6 +14,7 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding;
 public class FormValueProvider : BindingSourceValueProvider, IEnumerableValueProvider
 {
     private readonly IFormCollection _values;
+    private readonly HashSet<string?>? _invariantValueKeys;
     private PrefixContainer? _prefixContainer;
 
     /// <summary>
@@ -22,10 +23,12 @@ public class FormValueProvider : BindingSourceValueProvider, IEnumerableValuePro
     /// <param name="bindingSource">The <see cref="BindingSource"/> for the data.</param>
     /// <param name="values">The key value pairs to wrap.</param>
     /// <param name="culture">The culture to return with ValueProviderResult instances.</param>
+    /// <param name="options">The <see cref="MvcOptions"/> options.</param>
     public FormValueProvider(
         BindingSource bindingSource,
         IFormCollection values,
-        CultureInfo? culture)
+        CultureInfo? culture,
+        MvcOptions? options)
         : base(bindingSource)
     {
         if (bindingSource == null)
@@ -39,9 +42,30 @@ public FormValueProvider(
         }
 
         _values = values;
+
+        var suppressCultureInvariantFormModelBinding = options?.SuppressCultureInvariantFormModelBinding == true;
+        if (!suppressCultureInvariantFormModelBinding && _values.TryGetValue(FormModelBindingHelper.CultureInvariantFieldName, out var invariantKeys))
+        {
+            _invariantValueKeys = new(invariantKeys, StringComparer.OrdinalIgnoreCase);
+        }
+
         Culture = culture;
     }
 
+    /// <summary>
+    /// Creates a value provider for <see cref="IFormCollection"/>.
+    /// </summary>
+    /// <param name="bindingSource">The <see cref="BindingSource"/> for the data.</param>
+    /// <param name="values">The key value pairs to wrap.</param>
+    /// <param name="culture">The culture to return with ValueProviderResult instances.</param>
+    public FormValueProvider(
+        BindingSource bindingSource,
+        IFormCollection values,
+        CultureInfo? culture)
+        : this(bindingSource, values, culture, options: null)
+    {
+    }
+
     /// <summary>
     /// The culture to use.
     /// </summary>
@@ -104,7 +128,8 @@ public override ValueProviderResult GetValue(string key)
         }
         else
         {
-            return new ValueProviderResult(values, Culture);
+            var culture = _invariantValueKeys?.Contains(key) == true ? CultureInfo.InvariantCulture : Culture;
+            return new ValueProviderResult(values, culture);
         }
     }
 }

src/Mvc/Mvc.Core/src/ModelBinding/FormValueProviderFactory.cs

@@ -14,6 +14,25 @@ namespace Microsoft.AspNetCore.Mvc.ModelBinding;
 /// </summary>
 public class FormValueProviderFactory : IValueProviderFactory
 {
+    private readonly MvcOptions? _options;
+
+    /// <summary>
+    /// Creates a new <see cref="FormValueProviderFactory"/>.
+    /// </summary>
+    /// <param name="options">The <see cref="MvcOptions"/> options.</param>
+    public FormValueProviderFactory(MvcOptions? options)
+    {
+        _options = options;
+    }
+
+    /// <summary>
+    /// Creates a new <see cref="FormValueProviderFactory"/>.
+    /// </summary>
+    public FormValueProviderFactory()
+        : this(options: null)
+    {
+    }
+
     /// <inheritdoc />
     public Task CreateValueProviderAsync(ValueProviderFactoryContext context)
     {
@@ -26,13 +45,13 @@ public Task CreateValueProviderAsync(ValueProviderFactoryContext context)
         if (request.HasFormContentType)
         {
             // Allocating a Task only when the body is form data.
-            return AddValueProviderAsync(context);
+            return AddValueProviderAsync(context, _options);
         }
 
         return Task.CompletedTask;
     }
 
-    private static async Task AddValueProviderAsync(ValueProviderFactoryContext context)
+    private static async Task AddValueProviderAsync(ValueProviderFactoryContext context, MvcOptions? options)
     {
         var request = context.ActionContext.HttpContext.Request;
         IFormCollection form;
@@ -57,7 +76,8 @@ private static async Task AddValueProviderAsync(ValueProviderFactoryContext cont
         var valueProvider = new FormValueProvider(
             BindingSource.Form,
             form,
-            CultureInfo.CurrentCulture);
+            CultureInfo.CurrentCulture,
+            options);
 
         context.ValueProviders.Add(valueProvider);
     }

src/Mvc/Mvc.Core/src/MvcOptions.cs

@@ -3,6 +3,7 @@
 
 using System.Collections;
 using System.ComponentModel.DataAnnotations;
+using System.Globalization;
 using Microsoft.AspNetCore.Mvc.Abstractions;
 using Microsoft.AspNetCore.Mvc.ApplicationModels;
 using Microsoft.AspNetCore.Mvc.Controllers;
@@ -379,6 +380,19 @@ public int MaxModelBindingRecursionDepth
     /// <value>Defaults to <c>8192</c>.</value>
     public int MaxIAsyncEnumerableBufferLimit { get; set; } = 8192;
 
+    /// <summary>
+    /// Gets or sets a value that determines if form values are disallowed to be
+    /// parsed using <see cref="CultureInfo.InvariantCulture"/>.
+    /// </summary>
+    /// <remarks>
+    /// Some form elements (e.g., &lt;input type="text"/&gt;) require culture-specific formatting and parsing because their values are
+    /// directly entered by the user. However, other inputs (e.g., &lt;input type="number"/&gt;) use culture-invariant
+    /// formatting both in the HTML source and in the form request. Setting this property to <see langword="true"/>
+    /// will result in <see cref="CultureInfo.CurrentCulture"/> always being used to parse form values regardless of
+    /// their original format.
+    /// </remarks>
+    public bool SuppressCultureInvariantFormModelBinding { get; set; }
+
     IEnumerator<ICompatibilitySwitch> IEnumerable<ICompatibilitySwitch>.GetEnumerator() => _switches.GetEnumerator();
 
     IEnumerator IEnumerable.GetEnumerator() => _switches.GetEnumerator();

src/Mvc/Mvc.Core/src/PublicAPI.Unshipped.txt

@@ -7,6 +7,10 @@ Microsoft.AspNetCore.Mvc.ApplicationModels.InferParameterBindingInfoConvention.I
 *REMOVED*Microsoft.AspNetCore.Mvc.ControllerBase.TryUpdateModelAsync<TModel>(TModel! model, string! prefix, params System.Linq.Expressions.Expression<System.Func<TModel!, object!>!>![]! includeExpressions) -> System.Threading.Tasks.Task<bool>!
 Microsoft.AspNetCore.Mvc.ControllerBase.TryUpdateModelAsync<TModel>(TModel! model, string! prefix, Microsoft.AspNetCore.Mvc.ModelBinding.IValueProvider! valueProvider, params System.Linq.Expressions.Expression<System.Func<TModel!, object?>!>![]! includeExpressions) -> System.Threading.Tasks.Task<bool>!
 Microsoft.AspNetCore.Mvc.ControllerBase.TryUpdateModelAsync<TModel>(TModel! model, string! prefix, params System.Linq.Expressions.Expression<System.Func<TModel!, object?>!>![]! includeExpressions) -> System.Threading.Tasks.Task<bool>!
+Microsoft.AspNetCore.Mvc.ModelBinding.FormValueProvider.FormValueProvider(Microsoft.AspNetCore.Mvc.ModelBinding.BindingSource! bindingSource, Microsoft.AspNetCore.Http.IFormCollection! values, System.Globalization.CultureInfo? culture, Microsoft.AspNetCore.Mvc.MvcOptions? options) -> void
+Microsoft.AspNetCore.Mvc.ModelBinding.FormValueProviderFactory.FormValueProviderFactory(Microsoft.AspNetCore.Mvc.MvcOptions? options) -> void
+Microsoft.AspNetCore.Mvc.MvcOptions.SuppressCultureInvariantFormModelBinding.get -> bool
+Microsoft.AspNetCore.Mvc.MvcOptions.SuppressCultureInvariantFormModelBinding.set -> void
 Microsoft.AspNetCore.Mvc.ProblemDetails (forwarded, contained in Microsoft.AspNetCore.Http.Abstractions)
 Microsoft.AspNetCore.Mvc.ProblemDetails.Detail.get -> string? (forwarded, contained in Microsoft.AspNetCore.Http.Abstractions)
 Microsoft.AspNetCore.Mvc.ProblemDetails.Detail.set -> void (forwarded, contained in Microsoft.AspNetCore.Http.Abstractions)

src/Mvc/Mvc.TagHelpers/src/InputTagHelper.cs

@@ -241,6 +241,12 @@ public override void Process(TagHelperContext context, TagHelperOutput output)
                 break;
         }
 
+        if (!ViewContext.SuppressCultureInvariantFormElementValueFormatting &&
+            FormModelBindingHelper.InputTypeUsesCultureInvariantFormatting(inputType))
+        {
+            GenerateInvariantCultureMetadata(For.Name, output.PostElement);
+        }
+
         if (tagBuilder != null)
         {
             // This TagBuilder contains the one <input/> element of interest.
@@ -410,6 +416,14 @@ private TagBuilder GenerateTextBox(
             htmlAttributes);
     }
 
+    private static void GenerateInvariantCultureMetadata(string propertyName, TagHelperContent builder)
+        => builder
+            .AppendHtml("<input name=\"")
+            .Append(FormModelBindingHelper.CultureInvariantFieldName)
+            .AppendHtml("\" type=\"hidden\" value=\"")
+            .Append(propertyName)
+            .AppendHtml("\" />");
+
     // Imitate Generator.GenerateHidden() using Generator.GenerateTextBox(). This adds support for asp-format that
     // is not available in Generator.GenerateHidden().
     private TagBuilder GenerateHidden(ModelExplorer modelExplorer, IDictionary<string, object> htmlAttributes)

src/Mvc/Mvc.ViewFeatures/src/DefaultHtmlGenerator.cs

@@ -40,6 +40,7 @@ public class DefaultHtmlGenerator : IHtmlGenerator
     private readonly IUrlHelperFactory _urlHelperFactory;
     private readonly HtmlEncoder _htmlEncoder;
     private readonly ValidationHtmlAttributeProvider _validationAttributeProvider;
+    private readonly bool _suppressCultureInvariantFormatting;
 
     /// <summary>
     /// Initializes a new instance of the <see cref="DefaultHtmlGenerator"/> class.
@@ -94,6 +95,7 @@ public DefaultHtmlGenerator(
         _urlHelperFactory = urlHelperFactory;
         _htmlEncoder = htmlEncoder;
         _validationAttributeProvider = validationAttributeProvider;
+        _suppressCultureInvariantFormatting = optionsAccessor.Value.HtmlHelperOptions.SuppressCultureInvariantFormValueFormatting;
 
         // Underscores are fine characters in id's.
         IdAttributeDotReplacement = optionsAccessor.Value.HtmlHelperOptions.IdAttributeDotReplacement;
@@ -134,7 +136,12 @@ public string Encode(object value)
     /// <inheritdoc />
     public string FormatValue(object value, string format)
     {
-        return ViewDataDictionary.FormatValue(value, format);
+        return ViewDataDictionary.FormatValue(value, format, CultureInfo.CurrentCulture);
+    }
+
+    private static string FormatValue(object value, string format, IFormatProvider formatProvider)
+    {
+        return ViewDataDictionary.FormatValue(value, format, formatProvider);
     }
 
     /// <inheritdoc />
@@ -1282,7 +1289,10 @@ protected virtual TagBuilder GenerateInput(
             AddMaxLengthAttribute(viewContext.ViewData, tagBuilder, modelExplorer, expression);
         }
 
-        var valueParameter = FormatValue(value, format);
+        var culture = !_suppressCultureInvariantFormatting && FormModelBindingHelper.InputTypeUsesCultureInvariantFormatting(suppliedTypeString)
+            ? CultureInfo.InvariantCulture
+            : CultureInfo.CurrentCulture;
+        var valueParameter = FormatValue(value, format, culture);
         var usedModelState = false;
         switch (inputType)
         {
@@ -1329,27 +1339,15 @@ protected virtual TagBuilder GenerateInput(
 
             case InputType.Text:
             default:
-                var attributeValue = (string)GetModelStateValue(viewContext, fullName, typeof(string));
-                if (attributeValue == null)
-                {
-                    attributeValue = useViewData ? EvalString(viewContext, expression, format) : valueParameter;
-                }
-
-                var addValue = true;
-                object typeAttributeValue;
-                if (htmlAttributes != null && htmlAttributes.TryGetValue("type", out typeAttributeValue))
+                if (string.Equals(suppliedTypeString, "file", StringComparison.OrdinalIgnoreCase) ||
+                    string.Equals(suppliedTypeString, "image", StringComparison.OrdinalIgnoreCase))
                 {
-                    var typeAttributeString = typeAttributeValue.ToString();
-                    if (string.Equals(typeAttributeString, "file", StringComparison.OrdinalIgnoreCase) ||
-                        string.Equals(typeAttributeString, "image", StringComparison.OrdinalIgnoreCase))
-                    {
-                        // 'value' attribute is not needed for 'file' and 'image' input types.
-                        addValue = false;
-                    }
+                    // 'value' attribute is not needed for 'file' and 'image' input types.
                 }
-
-                if (addValue)
+                else
                 {
+                    var attributeValue = (string)GetModelStateValue(viewContext, fullName, typeof(string));
+                    attributeValue ??= useViewData ? EvalString(viewContext, expression, format) : valueParameter;
                     tagBuilder.MergeAttribute("value", attributeValue, replaceExisting: isExplicitValue);
                 }
 

src/Mvc/Mvc.ViewFeatures/src/HtmlHelperOptions.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+using System.Globalization;
 using Microsoft.AspNetCore.Mvc.Rendering;
 
 namespace Microsoft.AspNetCore.Mvc.ViewFeatures;
@@ -60,4 +61,17 @@ public string IdAttributeDotReplacement
     /// Gets or sets the way hidden inputs are rendered for checkbox tag helpers and html helpers.
     /// </summary>
     public CheckBoxHiddenInputRenderMode CheckBoxHiddenInputRenderMode { get; set; } = CheckBoxHiddenInputRenderMode.EndOfForm;
+
+    /// <summary>
+    /// Gets or sets a value that determines if form element values are disallowed to be
+    /// formatted using <see cref="CultureInfo.InvariantCulture"/>.
+    /// </summary>
+    /// <remarks>
+    /// Some form elements (e.g., &lt;input type="text"/&gt;) require culture-specific formatting and parsing because their values are
+    /// directly entered by the user. However, other inputs (e.g., &lt;input type="number"/&gt;) use culture-invariant
+    /// formatting both in the HTML source and in the form request. Setting this property to <see langword="true"/>
+    /// will result in <see cref="CultureInfo.CurrentCulture"/> always being used to format form element values. This may result in
+    /// invalid HTML being generated.
+    /// </remarks>
+    public bool SuppressCultureInvariantFormValueFormatting { get; set; }
 }

src/Mvc/Mvc.ViewFeatures/src/PublicAPI.Unshipped.txt

@@ -1,3 +1,8 @@
 #nullable enable
 *REMOVED*Microsoft.AspNetCore.Mvc.ViewFeatures.ViewDataDictionary<TModel>.Model.get -> TModel?
+Microsoft.AspNetCore.Mvc.Rendering.ViewContext.SuppressCultureInvariantFormElementValueFormatting.get -> bool
+Microsoft.AspNetCore.Mvc.Rendering.ViewContext.SuppressCultureInvariantFormElementValueFormatting.set -> void
+Microsoft.AspNetCore.Mvc.ViewFeatures.HtmlHelperOptions.SuppressCultureInvariantFormValueFormatting.get -> bool
+Microsoft.AspNetCore.Mvc.ViewFeatures.HtmlHelperOptions.SuppressCultureInvariantFormValueFormatting.set -> void
 Microsoft.AspNetCore.Mvc.ViewFeatures.ViewDataDictionary<TModel>.Model.get -> TModel
+static Microsoft.AspNetCore.Mvc.ViewFeatures.ViewDataDictionary.FormatValue(object? value, string? format, System.IFormatProvider! formatProvider) -> string?

src/Mvc/Mvc.ViewFeatures/src/Rendering/ViewContext.cs

@@ -3,6 +3,7 @@
 
 #nullable enable
 
+using System.Globalization;
 using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Microsoft.AspNetCore.Mvc.ViewEngines;
 using Microsoft.AspNetCore.Mvc.ViewFeatures;
@@ -93,6 +94,7 @@ public ViewContext(
         ValidationSummaryMessageElement = htmlHelperOptions.ValidationSummaryMessageElement;
         ValidationMessageElement = htmlHelperOptions.ValidationMessageElement;
         CheckBoxHiddenInputRenderMode = htmlHelperOptions.CheckBoxHiddenInputRenderMode;
+        SuppressCultureInvariantFormElementValueFormatting = htmlHelperOptions.SuppressCultureInvariantFormValueFormatting;
     }
 
     /// <summary>
@@ -136,6 +138,7 @@ public ViewContext(
         ValidationSummaryMessageElement = viewContext.ValidationSummaryMessageElement;
         ValidationMessageElement = viewContext.ValidationMessageElement;
         CheckBoxHiddenInputRenderMode = viewContext.CheckBoxHiddenInputRenderMode;
+        SuppressCultureInvariantFormElementValueFormatting = viewContext.SuppressCultureInvariantFormElementValueFormatting;
 
         ExecutingFilePath = viewContext.ExecutingFilePath;
         View = view;
@@ -195,6 +198,19 @@ public virtual FormContext FormContext
     /// </summary>
     public CheckBoxHiddenInputRenderMode CheckBoxHiddenInputRenderMode { get; set; }
 
+    /// <summary>
+    /// Gets or sets a value that determines if form element values are disallowed to be
+    /// formatted using <see cref="CultureInfo.InvariantCulture"/>.
+    /// </summary>
+    /// <remarks>
+    /// Some form elements (e.g., &lt;input type="text"/&gt;) require culture-specific formatting and parsing because their values are
+    /// directly entered by the user. However, other inputs (e.g., &lt;input type="number"/&gt;) use culture-invariant
+    /// formatting both in the HTML source and in the form request. Setting this property to <see langword="true"/>
+    /// will result in <see cref="CultureInfo.CurrentCulture"/> always being used to format form element values. This may result in
+    /// invalid HTML being generated.
+    /// </remarks>
+    public bool SuppressCultureInvariantFormElementValueFormatting { get; set; }
+
     /// <summary>
     /// Gets the dynamic view bag.
     /// </summary>