Handle "month" input type (#7022)

Addresses #6615

src/Microsoft.AspNetCore.Mvc.TagHelpers/InputTagHelper.cs

@@ -36,6 +36,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                 { "DateTime-local", "datetime-local" },
                 { nameof(DateTimeOffset), "text" },
                 { "Time", "time" },
+                { "Month", "month" },
                 { nameof(Byte), "number" },
                 { nameof(SByte), "number" },
                 { nameof(Int16), "number" },
@@ -378,7 +379,12 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
         private string GetFormat(ModelExplorer modelExplorer, string inputTypeHint, string inputType)
         {
             string format;
-            if (string.Equals("decimal", inputTypeHint, StringComparison.OrdinalIgnoreCase) &&
+            if (string.Equals("month", inputType, StringComparison.OrdinalIgnoreCase))
+            {
+                // A new HTML5 input type that only will be rendered in Rfc3339 mode
+                format = "{0:yyyy-MM}";
+            }
+            else if (string.Equals("decimal", inputTypeHint, StringComparison.OrdinalIgnoreCase) &&
                 string.Equals("text", inputType, StringComparison.Ordinal) &&
                 string.IsNullOrEmpty(modelExplorer.Metadata.EditFormatString))
             {

src/Microsoft.AspNetCore.Mvc.ViewFeatures/Internal/DefaultEditorTemplates.cs

@@ -370,6 +370,14 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
             return GenerateTextBox(htmlHelper, inputType: "time");
         }
 
+        public static IHtmlContent MonthInputTemplate(IHtmlHelper htmlHelper)
+        {
+            // A new HTML5 input type that only will be rendered in Rfc3339 mode
+            htmlHelper.Html5DateRenderingMode = Html5DateRenderingMode.Rfc3339;
+            ApplyRfc3339DateFormattingIfNeeded(htmlHelper, "{0:yyyy-MM}");
+            return GenerateTextBox(htmlHelper, inputType: "month");
+        }
+
         public static IHtmlContent NumberInputTemplate(IHtmlHelper htmlHelper)
         {
             return GenerateTextBox(htmlHelper, inputType: "number");

src/Microsoft.AspNetCore.Mvc.ViewFeatures/ViewFeatures/TemplateRenderer.cs

@@ -52,6 +52,7 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
                 { "DateTime-local", DefaultEditorTemplates.DateTimeLocalInputTemplate },
                 { nameof(DateTimeOffset), DefaultEditorTemplates.DateTimeOffsetTemplate },
                 { "Time", DefaultEditorTemplates.TimeInputTemplate },
+                { "Month", DefaultEditorTemplates.MonthInputTemplate },
                 { typeof(byte).Name, DefaultEditorTemplates.NumberInputTemplate },
                 { typeof(sbyte).Name, DefaultEditorTemplates.NumberInputTemplate },
                 { typeof(short).Name, DefaultEditorTemplates.NumberInputTemplate },

test/Microsoft.AspNetCore.Mvc.TagHelpers.Test/InputTagHelperTest.cs

@@ -1052,6 +1052,7 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
                     { "text", null, "text" },
                     { "TEXT", null, "text" },
                     { "time", null, "time" },
+                    { "month", "{0:yyyy-MM}", "month" },
                     { "UInt16", null, "number" },
                     { "uint16", null, "number" },
                     { "UInt32", null, "number" },
@@ -1217,6 +1218,8 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
         [InlineData("DateTimeLocal", Html5DateRenderingMode.Rfc3339, "{0:yyyy-MM-ddTHH:mm:ss.fff}", "datetime-local")]
         [InlineData("Time", Html5DateRenderingMode.CurrentCulture, "{0:t}", "time")]    // Format from [DataType].
         [InlineData("Time", Html5DateRenderingMode.Rfc3339, "{0:HH:mm:ss.fff}", "time")]
+        [InlineData("Month", Html5DateRenderingMode.CurrentCulture, "{0:yyyy-MM}", "month")]
+        [InlineData("Month", Html5DateRenderingMode.Rfc3339, "{0:yyyy-MM}", "month")]
         [InlineData("NullableDate", Html5DateRenderingMode.Rfc3339, "{0:yyyy-MM-dd}", "date")]
         [InlineData("NullableDateTime", Html5DateRenderingMode.Rfc3339, "{0:yyyy-MM-ddTHH:mm:ss.fff}", "datetime-local")]
         [InlineData("NullableDateTimeOffset", Html5DateRenderingMode.Rfc3339, "{0:yyyy-MM-ddTHH:mm:ss.fffK}", "text")]
@@ -1377,6 +1380,9 @@ namespace Microsoft.AspNetCore.Mvc.TagHelpers
 
             [DataType(DataType.Time)]
             public DateTimeOffset Time { get; set; }
+
+            [DataType("month")]
+            public DateTimeOffset Month { get; set; }
         }
 
         private class NestedModel

test/Microsoft.AspNetCore.Mvc.ViewFeatures.Test/Internal/DefaultEditorTemplatesTest.cs

@@ -57,6 +57,8 @@ namespace Microsoft.AspNetCore.Mvc.ViewFeatures.Internal
                     { "DateTimeOffset", "__TextBox__ class='text-box single-line' type='text'" },
                     { "Time", "__TextBox__ class='text-box single-line' type='time'" },
                     { "time", "__TextBox__ class='text-box single-line' type='time'" },
+                    { "Month", "__TextBox__ class='text-box single-line' type='month'" },
+                    { "month", "__TextBox__ class='text-box single-line' type='month'" },
                     { "Byte", "__TextBox__ class='text-box single-line' type='number'" },
                     { "BYTE", "__TextBox__ class='text-box single-line' type='number'" },
                     { "SByte", "__TextBox__ class='text-box single-line' type='number'" },
@@ -825,6 +827,7 @@ Environment.NewLine;
         [InlineData("datetime-local", null, "2000-01-02T03:04:05.060", "datetime-local")]
         [InlineData("DateTimeOffset", "{0:o}", "2000-01-02T03:04:05.060-05:00", "text")]
         [InlineData("time", "{0:t}", "03:04:05.060", "time")]
+        [InlineData("month", "{0:yyyy-MM}", "2000-01", "month")]
         public void Editor_FindsCorrectDateOrTimeTemplate(
             string dataTypeName,
             string editFormatString,
@@ -886,6 +889,7 @@ Environment.NewLine;
         [InlineData("datetime-local", null, "02/01/2000 03:04:05 -05:00", "datetime-local")]
         [InlineData("DateTimeOffset", "{0:o}", "2000-01-02T03:04:05.0600000-05:00", "text")]
         [InlineData("time", "{0:t}", "03:04", "time")]
+        [InlineData("month", "{0:yyyy-MM}", "2000-01", "month")]
         [ReplaceCulture]
         public void Editor_FindsCorrectDateOrTimeTemplate_NotRfc3339(
             string dataTypeName,
@@ -950,6 +954,7 @@ Environment.NewLine;
         [InlineData("datetime-local", null, "2000-01-02T03:04:05.060", "datetime-local")]
         [InlineData("DateTimeOffset", "{0:o}", "2000-01-02T03:04:05.060Z", "text")]
         [InlineData("time", "{0:t}", "03:04:05.060", "time")]
+        [InlineData("month", "{0:yyyy-MM}", "2000-01", "month")]
         public void Editor_FindsCorrectDateOrTimeTemplate_ForDateTime(
             string dataTypeName,
             string editFormatString,
@@ -1010,6 +1015,7 @@ Environment.NewLine;
         [InlineData("datetime-local", null, "02/01/2000 03:04:05", "datetime-local")]
         [InlineData("DateTimeOffset", "{0:o}", "2000-01-02T03:04:05.0600000Z", "text")]
         [InlineData("time", "{0:t}", "03:04", "time")]
+        [InlineData("month", "{0:yyyy-MM}", "2000-01", "month")]
         [ReplaceCulture]
         public void Editor_FindsCorrectDateOrTimeTemplate_ForDateTimeNotRfc3339(
             string dataTypeName,
@@ -1076,6 +1082,8 @@ Environment.NewLine;
         [InlineData("datetime-local", Html5DateRenderingMode.Rfc3339, "datetime-local")]
         [InlineData("time", Html5DateRenderingMode.CurrentCulture, "time")]
         [InlineData("time", Html5DateRenderingMode.Rfc3339, "time")]
+        [InlineData("month", Html5DateRenderingMode.CurrentCulture, "month")]
+        [InlineData("month", Html5DateRenderingMode.Rfc3339, "month")]
         public void Editor_AppliesNonDefaultEditFormat(string dataTypeName, Html5DateRenderingMode renderingMode, string expectedType)
         {
             // Arrange