Issue #2123 - Adding AppendFormat to TagHelperContent.

src/Microsoft.AspNet.Razor.Runtime/TagHelpers/DefaultTagHelperContent.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.Collections.Generic;
 using System.IO;
 using Microsoft.Framework.Internal;
@@ -89,6 +90,72 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             return this;
         }
 
+        /// <inheritdoc />
+        public override TagHelperContent AppendFormat(string format, object arg0)
+        {
+            _buffer.Add(string.Format(format, arg0));
+            return this;
+        }
+
+        /// <inheritdoc />
+        public override TagHelperContent AppendFormat(string format, object arg0, object arg1)
+        {
+            _buffer.Add(string.Format(format, arg0, arg1));
+            return this;
+        }
+
+        /// <inheritdoc />
+        public override TagHelperContent AppendFormat(string format, object arg0, object arg1, object arg2)
+        {
+            _buffer.Add(string.Format(format, arg0, arg1, arg2));
+            return this;
+        }
+
+        /// <inheritdoc />
+        public override TagHelperContent AppendFormat([NotNull] string format, params object[] args)
+        {
+            _buffer.Add(string.Format(format, args));
+            return this;
+        }
+
+        /// <inheritdoc />
+        public override TagHelperContent AppendFormat(IFormatProvider provider, string format, object arg0)
+        {
+            _buffer.Add(string.Format(provider, format, arg0));
+            return this;
+        }
+
+        /// <inheritdoc />
+        public override TagHelperContent AppendFormat(
+            IFormatProvider provider,
+            string format,
+            object arg0,
+            object arg1)
+        {
+            _buffer.Add(string.Format(provider, format, arg0, arg1));
+            return this;
+        }
+
+        /// <inheritdoc />
+        public override TagHelperContent AppendFormat(
+            IFormatProvider provider,
+            string format,
+            object arg0,
+            object arg1,
+            object arg2)
+        {
+            _buffer.Add(string.Format(provider, format, arg0, arg1, arg2));
+            return this;
+        }
+
+        /// <inheritdoc />
+        public override TagHelperContent AppendFormat(
+            [NotNull] IFormatProvider provider, [NotNull] string format, params object[] args)
+        {
+            _buffer.Add(string.Format(provider, format, args));
+            return this;
+        }
+
         /// <inheritdoc />
         public override TagHelperContent Append(TagHelperContent tagHelperContent)
         {

src/Microsoft.AspNet.Razor.Runtime/TagHelpers/TagHelperContent.cs

@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
 using System.Collections;
 using System.Collections.Generic;
 
@@ -47,6 +48,122 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
         /// <returns>A reference to this instance after the append operation has completed.</returns>
         public abstract TagHelperContent Append(string value);
 
+        /// <summary>
+        /// Appends the specified <paramref name="format"/> to the existing content after
+        /// replacing the format item with the <see cref="string"/> representation of the
+        /// <paramref name="arg0"/>.
+        /// </summary>
+        /// <param name="format">
+        /// The composite format <see cref="string"/> (see http://msdn.microsoft.com/en-us/library/txafckwd.aspx).
+        /// </param>
+        /// <param name="arg0">The object to format.</param>
+        /// <returns>A reference to this instance after the append operation has completed.</returns>
+        public abstract TagHelperContent AppendFormat(string format, object arg0);
+
+        /// <summary>
+        /// Appends the specified <paramref name="format"/> to the existing content after
+        /// replacing each format item with the <see cref="string"/> representation of the
+        /// <paramref name="arg0"/> and <paramref name="arg1"/>.
+        /// </summary>
+        /// <param name="format">
+        /// The composite format <see cref="string"/> (see http://msdn.microsoft.com/en-us/library/txafckwd.aspx).
+        /// </param>
+        /// <param name="arg0">The object to format.</param>
+        /// <param name="arg1">The object to format.</param>
+        /// <returns>A reference to this instance after the append operation has completed.</returns>
+        public abstract TagHelperContent AppendFormat(string format, object arg0, object arg1);
+
+        /// <summary>
+        /// Appends the specified <paramref name="format"/> to the existing content after
+        /// replacing each format item with the <see cref="string"/> representation of the
+        /// <paramref name="arg0"/>, <paramref name="arg1"/> and <paramref name="arg2"/>.
+        /// </summary>
+        /// <param name="format">
+        /// The composite format <see cref="string"/> (see http://msdn.microsoft.com/en-us/library/txafckwd.aspx).
+        /// </param>
+        /// <param name="arg0">The object to format.</param>
+        /// <param name="arg1">The object to format.</param>
+        /// <param name="arg2">The object to format.</param>
+        /// <returns>A reference to this instance after the append operation has completed.</returns>
+        public abstract TagHelperContent AppendFormat(string format, object arg0, object arg1, object arg2);
+
+        /// <summary>
+        /// Appends the specified <paramref name="format"/> to the existing content after
+        /// replacing each format item with the <see cref="string"/> representation of the
+        /// corresponding item in the <paramref name="args"/> array.
+        /// </summary>
+        /// <param name="format">
+        /// The composite format <see cref="string"/> (see http://msdn.microsoft.com/en-us/library/txafckwd.aspx).
+        /// </param>
+        /// <param name="args">The object array to format.</param>
+        /// <returns>A reference to this instance after the append operation has completed.</returns>
+        public abstract TagHelperContent AppendFormat(string format, params object[] args);
+
+        /// <summary>
+        /// Appends the specified <paramref name="format"/> to the existing content with information from the
+        /// <paramref name="provider"/> after replacing the format item with the <see cref="string"/>
+        /// representation of the corresponding item in <paramref name="arg0"/>.
+        /// </summary>
+        /// <param name="provider">An object that supplies culture-specific formatting information.</param>
+        /// <param name="format">
+        /// The composite format <see cref="string"/> (see http://msdn.microsoft.com/en-us/library/txafckwd.aspx).
+        /// </param>
+        /// <param name="arg0">The object to format.</param>
+        /// <returns>A reference to this instance after the append operation has completed.</returns>
+        public abstract TagHelperContent AppendFormat(IFormatProvider provider, string format, object arg0);
+
+        /// <summary>
+        /// Appends the specified <paramref name="format"/> to the existing content with information from the
+        /// <paramref name="provider"/> after replacing each format item with the <see cref="string"/>
+        /// representation of the corresponding item in <paramref name="arg0"/> and <paramref name="arg1"/>.
+        /// </summary>
+        /// <param name="provider">An object that supplies culture-specific formatting information.</param>
+        /// <param name="format">
+        /// The composite format <see cref="string"/> (see http://msdn.microsoft.com/en-us/library/txafckwd.aspx).
+        /// </param>
+        /// <param name="arg0">The object to format.</param>
+        /// <param name="arg1">The object to format.</param>
+        /// <returns>A reference to this instance after the append operation has completed.</returns>
+        public abstract TagHelperContent AppendFormat(
+            IFormatProvider provider,
+            string format,
+            object arg0,
+            object arg1);
+
+        /// <summary>
+        /// Appends the specified <paramref name="format"/> to the existing content with information from the
+        /// <paramref name="provider"/> after replacing each format item with the <see cref="string"/>
+        /// representation of the corresponding item in <paramref name="arg0"/>, <paramref name="arg1"/>
+        /// and <paramref name="arg2"/>.
+        /// </summary>
+        /// <param name="provider">An object that supplies culture-specific formatting information.</param>
+        /// <param name="format">
+        /// The composite format <see cref="string"/> (see http://msdn.microsoft.com/en-us/library/txafckwd.aspx).
+        /// </param>
+        /// <param name="arg0">The object to format.</param>
+        /// <param name="arg1">The object to format.</param>
+        /// <param name="arg2">The object to format.</param>
+        /// <returns>A reference to this instance after the append operation has completed.</returns>
+        public abstract TagHelperContent AppendFormat(
+            IFormatProvider provider,
+            string format,
+            object arg0,
+            object arg1,
+            object arg2);
+
+        /// <summary>
+        /// Appends the specified <paramref name="format"/> to the existing content with information from the
+        /// <paramref name="provider"/> after replacing each format item with the <see cref="string"/>
+        /// representation of the corresponding item in the <paramref name="args"/> array.
+        /// </summary>
+        /// <param name="provider">An object that supplies culture-specific formatting information.</param>
+        /// <param name="format">
+        /// The composite format <see cref="string"/> (see http://msdn.microsoft.com/en-us/library/txafckwd.aspx).
+        /// </param>
+        /// <param name="args">The object array to format.</param>
+        /// <returns>A reference to this instance after the append operation has completed.</returns>
+        public abstract TagHelperContent AppendFormat(IFormatProvider provider, string format, params object[] args);
+
         /// <summary>
         /// Appends <paramref name="tagHelperContent"/> to the existing content.
         /// </summary>

test/Microsoft.AspNet.Razor.Runtime.Test/TagHelpers/DefaultTagHelperContentTest.cs

@@ -2,8 +2,9 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
-using System.IO;
+using System.Globalization;
 using System.Linq;
+using Microsoft.AspNet.Testing;
 using Xunit;
 
 namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
@@ -86,6 +87,200 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             Assert.Equal(expected, tagHelperContent.GetContent());
         }
 
+        // Overload with args array is called.
+        [Fact]
+        public void CanAppendFormatContent()
+        {
+            // Arrange
+            var tagHelperContent = new DefaultTagHelperContent();
+
+            // Act
+            tagHelperContent.AppendFormat("{0} {1} {2} {3}!", "First", "Second", "Third", "Fourth");
+
+            // Assert
+            Assert.Equal("First Second Third Fourth!", tagHelperContent.GetContent());
+        }
+
+        [Fact]
+        public void CanAppendFormatContent_With1Argument()
+        {
+            // Arrange
+            var tagHelperContent = new DefaultTagHelperContent();
+
+            // Act
+            tagHelperContent.AppendFormat("0x{0, -5:X} - hex equivalent for 50.", 50);
+
+            // Assert
+            Assert.Equal("0x32    - hex equivalent for 50.", tagHelperContent.GetContent());
+        }
+
+        [Fact]
+        public void CanAppendFormatContent_With2Arguments()
+        {
+            // Arrange
+            var tagHelperContent = new DefaultTagHelperContent();
+
+            // Act
+            tagHelperContent.AppendFormat("0x{0, -5:X} - hex equivalent for {1}.", 50, 50);
+
+            // Assert
+            Assert.Equal("0x32    - hex equivalent for 50.", tagHelperContent.GetContent());
+        }
+
+        [Fact]
+        public void CanAppendFormatContent_With3Arguments()
+        {
+            // Arrange
+            var tagHelperContent = new DefaultTagHelperContent();
+
+            // Act
+            tagHelperContent.AppendFormat("0x{0, -5:X} - {1} equivalent for {2}.", 50, "hex", 50);
+
+            // Assert
+            Assert.Equal("0x32    - hex equivalent for 50.", tagHelperContent.GetContent());
+        }
+
+        [Fact]
+        public void CanAppendFormat_WithAlignmentComponent()
+        {
+            // Arrange
+            var tagHelperContent = new DefaultTagHelperContent();
+
+            // Act
+            tagHelperContent.AppendFormat("{0, -10} World!", "Hello");
+
+            // Assert
+            Assert.Equal("Hello      World!", tagHelperContent.GetContent());
+        }
+
+        [Fact]
+        public void CanAppendFormat_WithFormatStringComponent()
+        {
+            // Arrange
+            var tagHelperContent = new DefaultTagHelperContent();
+
+            // Act
+            tagHelperContent.AppendFormat("0x{0:X}", 50);
+
+            // Assert
+            Assert.Equal("0x32", tagHelperContent.GetContent());
+        }
+
+        // Overload with args array is called.
+        [Fact]
+        public void CanAppendFormat_WithCulture()
+        {
+            // Arrange
+            var tagHelperContent = new DefaultTagHelperContent();
+
+            // Act
+            tagHelperContent.AppendFormat(
+                CultureInfo.InvariantCulture,
+                "Numbers in InvariantCulture - {0, -5:N} {1} {2} {3}!",
+                1.1,
+                2.98,
+                145.82,
+                32.86);
+
+            // Assert
+            Assert.Equal("Numbers in InvariantCulture - 1.10  2.98 145.82 32.86!", tagHelperContent.GetContent());
+        }
+
+        [Fact]
+        public void CanAppendFormat_WithCulture_1Argument()
+        {
+            // Arrange
+            var tagHelperContent = new DefaultTagHelperContent();
+
+            // Act
+            tagHelperContent.AppendFormat(
+                CultureInfo.InvariantCulture,
+                "Numbers in InvariantCulture - {0, -5:N}!",
+                1.1);
+
+            // Assert
+            Assert.Equal("Numbers in InvariantCulture - 1.10 !", tagHelperContent.GetContent());
+        }
+
+        [Fact]
+        public void CanAppendFormat_WithCulture_2Arguments()
+        {
+            // Arrange
+            var tagHelperContent = new DefaultTagHelperContent();
+
+            // Act
+            tagHelperContent.AppendFormat(
+                CultureInfo.InvariantCulture,
+                "Numbers in InvariantCulture - {0, -5:N} {1}!",
+                1.1,
+                2.98);
+
+            // Assert
+            Assert.Equal("Numbers in InvariantCulture - 1.10  2.98!", tagHelperContent.GetContent());
+        }
+
+        [Fact]
+        public void CanAppendFormat_WithCulture_3Arguments()
+        {
+            // Arrange
+            var tagHelperContent = new DefaultTagHelperContent();
+
+            // Act
+            tagHelperContent.AppendFormat(
+                CultureInfo.InvariantCulture,
+                "Numbers in InvariantCulture - {0, -5:N} {1} {2}!",
+                1.1,
+                2.98,
+                3.12);
+
+            // Assert
+            Assert.Equal("Numbers in InvariantCulture - 1.10  2.98 3.12!", tagHelperContent.GetContent());
+        }
+
+        [Fact]
+        public void CanAppendFormat_WithDifferentCulture()
+        {
+            // Arrange
+            var tagHelperContent = new DefaultTagHelperContent();
+            var culture = new CultureInfo("fr-FR");
+
+            // Act
+            tagHelperContent.AppendFormat(culture, "{0} in french!", 1.21);
+
+            // Assert
+            Assert.Equal("1,21 in french!", tagHelperContent.GetContent());
+        }
+
+        [Fact]
+        [ReplaceCulture]
+        public void CanAppendFormat_WithDifferentCurrentCulture()
+        {
+            // Arrange
+            var tagHelperContent = new DefaultTagHelperContent();
+
+            // Act
+            tagHelperContent.AppendFormat(CultureInfo.CurrentCulture, "{0:D}", DateTime.Parse("01/02/2015"));
+
+            // Assert
+            Assert.Equal("01 February 2015", tagHelperContent.GetContent());
+        }
+
+        [Fact]
+        public void CanAppendDefaultTagHelperContent()
+        {
+            // Arrange
+            var tagHelperContent = new DefaultTagHelperContent();
+            var helloWorldContent = new DefaultTagHelperContent();
+            helloWorldContent.SetContent("HelloWorld");
+            var expected = "Content was HelloWorld";
+
+            // Act
+            tagHelperContent.AppendFormat("Content was {0}", helloWorldContent);
+
+            // Assert
+            Assert.Equal(expected, tagHelperContent.GetContent());
+        }
+
         [Fact]
         public void Append_WithTagHelperContent_MultipleAppends()
         {
@@ -359,6 +554,45 @@ namespace Microsoft.AspNet.Razor.Runtime.TagHelpers
             Assert.Equal(expected, tagHelperContent.GetContent());
         }
 
+        [Fact]
+        public void Fluent_SetContent_AppendFormat_WritesExpectedContent()
+        {
+            // Arrange
+            var tagHelperContent = new DefaultTagHelperContent();
+            var expected = new[] { "First ", "Second Third" };
+            var i = 0;
+
+            // Act
+            tagHelperContent.SetContent("First ").AppendFormat("{0} Third", "Second");
+
+            // Assert
+            foreach (var value in tagHelperContent)
+            {
+                Assert.Equal(expected[i++], value);
+            }
+        }
+
+        [Fact]
+        public void Fluent_SetContent_AppendFormat_Append_WritesExpectedContent()
+        {
+            // Arrange
+            var tagHelperContent = new DefaultTagHelperContent();
+            var expected = new[] { "First ", "Second Third ", "Fourth" };
+            var i = 0;
+
+            // Act
+            tagHelperContent
+                .SetContent("First ")
+                .AppendFormat("{0} Third ", "Second")
+                .Append("Fourth");
+
+            // Assert
+            foreach (var value in tagHelperContent)
+            {
+                Assert.Equal(expected[i++], value);
+            }
+        }
+
         [Fact]
         public void Fluent_Clear_SetContent_WritesExpectedContent()
         {