Merge pull request #2 from StuffOfInterest/feature-foreach

Feature foreach

.editorconfig

@@ -0,0 +1,4 @@
+[*.cs]
+
+# CS0162: Unreachable code detected
+dotnet_diagnostic.CS0162.severity = none

LogicTagHelpers.Demo/Controllers/HomeController.cs

@@ -18,5 +18,10 @@ public IActionResult TestSwitch()
 		{
 			return View();
 		}
+
+		public IActionResult TestForeach()
+		{
+			return View();
+		}
 	}
 }

LogicTagHelpers.Demo/Views/Home/Index.cshtml

@@ -5,4 +5,5 @@
 <ul>
 	<li><a asp-action="TestIf">Test If</a></li>
 	<li><a asp-action="TestSwitch">Test Switch</a></li>
+	<li><a asp-action="TestForeach">Test Foreach</a></li>
 </ul>

LogicTagHelpers.Demo/Views/Home/TestForeach.cshtml

@@ -0,0 +1,41 @@
+@{
+	var stringList = new[] { "one", "two", "three" };
+	var numberList = new[] { 1, 22, 333 };
+	var emptyList = new List<double>();
+}
+
+<h2>Test 1</h2>
+
+@{ var foreachContext = new ForeachContext<string>(stringList); }
+<foreach iterator="foreachContext">
+	<p>Should display @(foreachContext.Item).</p>
+</foreach>
+
+<h2>Test 2</h2>
+
+@{ var foreachContext2 = new ForeachContext<int>(numberList); }
+<foreach iterator="foreachContext2">
+	<p>Should display @(foreachContext2.Item).</p>
+</foreach>
+
+<h2>Test 3</h2>
+
+<p>Should not display any additional content.</p>
+
+@{ var foreachContext3 = new ForeachContext<double>(emptyList); }
+<foreach iterator="foreachContext3">
+	<p>Should not display @(foreachContext3.Item).</p>
+</foreach>
+
+<h2>Test 4</h2>
+
+@try
+{
+	<foreach>
+		<p>Should not display.</p>
+	</foreach>
+}
+catch (Exception ex)
+{
+	<p>Expected exception occurred: '@ex.Message'.</p>
+}

LogicTagHelpers.Demo/Views/Home/TestIf.cshtml

@@ -36,10 +36,10 @@ catch (Exception ex)
 <h2>Test 6</h2>
 @try
 {
-	<if condition="false">
-		<then>Should not display 1.</then>
-		<then>Should not display 2.</then>
-	</if>
+<if condition="false">
+	<then>Should not display 1.</then>
+	<then>Should not display 2.</then>
+</if>
 }
 catch (Exception ex)
 {
@@ -49,10 +49,10 @@ catch (Exception ex)
 <h2>Test 7</h2>
 @try
 {
-	<if condition="false">
-		<else>Should not display 1.</else>
-		<else>Should not display 2.</else>
-	</if>
+<if condition="false">
+	<else>Should not display 1.</else>
+	<else>Should not display 2.</else>
+</if>
 }
 catch (Exception ex)
 {

LogicTagHelpers.Tests/CreateClassTests.cs

@@ -64,5 +64,15 @@ public void CanCreateDefaultTagHelper()
 			// Assert
 			Assert.IsNotNull(result);
 		}
+
+		[TestMethod]
+		public void CanCreateForeachTagHelper()
+		{
+			// Act
+			var result = new ForeachTagHelper();
+
+			// Assert
+			Assert.IsNotNull(result);
+		}
 	}
 }

LogicTagHelpers.Tests/ForeachContextTests.cs

@@ -0,0 +1,56 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace LogicTagHelpers.Tests
+{
+	[TestClass]
+	public class ForeachContextTests
+	{
+		[TestMethod]
+		public void CanGetFirstRecord()
+		{
+			// Arrange
+			var list = new[] {"one", "two", "three"};
+			var context = new ForeachContext<string>(list);
+
+			// Act
+			var result = context.LoadNext();
+
+			// Assert
+			Assert.IsTrue(result);
+			Assert.AreEqual("one", context.Item);
+		}
+
+		[TestMethod]
+		public void CanGetSecondRecord()
+		{
+			// Arrange
+			var list = new[] { "one", "two", "three" };
+			var context = new ForeachContext<string>(list);
+			context.LoadNext();
+
+			// Act
+			var result = context.LoadNext();
+
+			// Assert
+			Assert.IsTrue(result);
+			Assert.AreEqual("two", context.Item);
+		}
+
+		[TestMethod]
+		public void AfterLastRecordReturnsFalse()
+		{
+			// Arrange
+			var list = new[] { "one", "two" };
+			var context = new ForeachContext<string>(list);
+			context.LoadNext();
+			context.LoadNext();
+
+			// Act
+			var result = context.LoadNext();
+
+			// Assert
+			Assert.IsFalse(result);
+			Assert.AreEqual("two", context.Item);
+		}
+	}
+}

LogicTagHelpers.sln

@@ -3,20 +3,21 @@ Microsoft Visual Studio Solution File, Format Version 12.00
 # Visual Studio Version 16
 VisualStudioVersion = 16.0.31205.134
 MinimumVisualStudioVersion = 10.0.40219.1
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LogicTagHelpers", "LogicTagHelpers\LogicTagHelpers.csproj", "{D853F062-7102-4514-8AAD-A423A630C3E2}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "LogicTagHelpers", "LogicTagHelpers\LogicTagHelpers.csproj", "{D853F062-7102-4514-8AAD-A423A630C3E2}"
 EndProject
-Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Build", "Build", "{A7C8F405-9E36-4AD8-AECC-BEE7220B41B4}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "LogicTagHelpers.Demo", "LogicTagHelpers.Demo\LogicTagHelpers.Demo.csproj", "{DE040CBB-9E3D-4D21-AD94-1C0262B5B513}"
+EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "LogicTagHelpers.Tests", "LogicTagHelpers.Tests\LogicTagHelpers.Tests.csproj", "{85652AC9-C0E4-4E21-87A7-BF6BE8D93E14}"
+EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{C75224D3-C733-4CB8-A7C6-446EFF3196A6}"
 	ProjectSection(SolutionItems) = preProject
+		.editorconfig = .editorconfig
 		.gitignore = .gitignore
 		.github\workflows\build-test-publish.yml = .github\workflows\build-test-publish.yml
 		.github\workflows\build-test.yml = .github\workflows\build-test.yml
 		README.md = README.md
 	EndProjectSection
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LogicTagHelpers.Demo", "LogicTagHelpers.Demo\LogicTagHelpers.Demo.csproj", "{DE040CBB-9E3D-4D21-AD94-1C0262B5B513}"
-EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LogicTagHelpers.Tests", "LogicTagHelpers.Tests\LogicTagHelpers.Tests.csproj", "{85652AC9-C0E4-4E21-87A7-BF6BE8D93E14}"
-EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU

LogicTagHelpers/ForeachContext.cs

@@ -0,0 +1,37 @@
+using System.Collections.Generic;
+
+namespace LogicTagHelpers
+{
+	/// <summary>
+	/// Generic implementation of a foreach context which can take any iterable object as a generic type.
+	/// </summary>
+	/// <typeparam name="T">Type of object to iterate over.</typeparam>
+	public class ForeachContext<T> : IForeachContext
+	{
+		public ForeachContext()
+		{
+		}
+
+		public ForeachContext(IEnumerable<T> items)
+		{
+			Collection = items;
+		}
+
+		private IEnumerator<T> _enumerator;
+
+		public IEnumerable<T> Collection { get; set; }
+		public T Item { get; set; }
+
+		public bool LoadNext()
+		{
+			var enumerator = _enumerator ??= Collection.GetEnumerator();
+			var result = enumerator.MoveNext();
+			if (result)
+			{
+				Item = enumerator.Current;
+			}
+
+			return result;
+		}
+	}
+}

LogicTagHelpers/ForeachTagHelper.cs

@@ -0,0 +1,35 @@
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Razor.TagHelpers;
+
+namespace LogicTagHelpers
+{
+	/// <summary>
+	/// Perform 'foreach' iteration over a set of data.
+	/// Inner content is rendered for each item in the iterator.
+	/// </summary>
+	[HtmlTargetElement("foreach")]
+	public class ForeachTagHelper : TagHelper
+	{
+		/// <summary>
+		/// Context which holds the collection to iterate over and a property for presenting the current item to the inner content.
+		/// </summary>
+		public IForeachContext Iterator { get; set; }
+
+		public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
+		{
+			if (Iterator == null)
+			{
+				throw new LogicTagHelperException("Iterator may not be null.");
+			}
+
+			output.TagName = null;
+			output.Content.Clear();
+
+			while (Iterator.LoadNext())
+			{
+				var childContent = await output.GetChildContentAsync(false);
+				output.Content.AppendHtml(childContent);
+			}
+		}
+	}
+}

LogicTagHelpers/IForeachContext.cs

@@ -0,0 +1,11 @@
+namespace LogicTagHelpers
+{
+	/// <summary>
+	/// Context for 'foreach' tag helper which holds the collection to iterator over
+	/// and presents each item to the tag helper content.
+	/// </summary>
+	public interface IForeachContext
+	{
+		bool LoadNext();
+	}
+}

LogicTagHelpers/LogicTagHelpers.csproj

@@ -3,7 +3,7 @@
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
-    <Version>0.2.0</Version>
+    <Version>0.3.0</Version>
     <Authors>Delbert Matlock</Authors>
     <Company>Stuff Of Interest</Company>
     <Product />
@@ -12,16 +12,21 @@
 Done:
 * if/then/else
 * switch/case/default
+* foreach
 
 Future:
-* foreach
 * while
 * for
 * do</Description>
     <PackageProjectUrl>https://github.com/StuffOfInterest/LogicTagHelpers</PackageProjectUrl>
     <RepositoryUrl>https://github.com/StuffOfInterest/LogicTagHelpers</RepositoryUrl>
+    <LangVersion>8</LangVersion>
   </PropertyGroup>
 
+  <ItemGroup>
+    <None Include="..\.editorconfig" Link=".editorconfig" />
+  </ItemGroup>
+
     <ItemGroup>
         <PackageReference Include="Microsoft.AspNetCore.Razor" Version="2.2.0" />
     </ItemGroup>

README.md

@@ -11,10 +11,10 @@
   * else
 * [switch](#switch)
   * case
+* [foreach](#foreach)
 
 ## Future Tags
 
-* foreach
 * while
 * for
 * do
@@ -53,3 +53,12 @@ Following line must be added to the `_ViewImports.cshtml` file for the logic tag
    <default>(content to display if no value match)</default>
 </switch>
 ```
+
+### foreach
+
+```cshtml
+@{ var context = new ForeachContext<(type)>((values-of-type)); }
+<foreach iterator="context">
+   (content to display for each item in collection)
+</foreach>
+```