Merge pull request #3 from StuffOfInterest/feature-while

Feature while

LogicTagHelpers.Demo/Controllers/HomeController.cs

@@ -23,5 +23,10 @@ public IActionResult TestForeach()
 		{
 			return View();
 		}
+
+		public IActionResult TestWhile()
+		{
+			return View();
+		}
 	}
 }

LogicTagHelpers.Demo/Views/Home/Index.cshtml

@@ -6,4 +6,5 @@
 	<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>
+	<li><a asp-action="TestWhile">Test While</a></li>
 </ul>

LogicTagHelpers.Demo/Views/Home/TestSwitch.cshtml

@@ -17,48 +17,91 @@
 
 <h2>Test 3</h2>
 
-@try
-{
-	<switch expression="2">
+@{ string errorResult = null; }
+<switch expression="4">
+	@try
+	{
 		<case value="1"><p>Should not display 1.</p></case>
 		<case value="2"><p>Should not display 2.</p></case>
 		<case value="2"><p>Should not display 3.</p></case>
 		<case value="2"><p>Should not display 4.</p></case>
-	</switch>
-}
-catch (LogicTagHelperException ex)
+	}
+	catch (LogicTagHelperException ex)
+	{
+		errorResult = $"Expected exception encountered: '{ex.Message}'.";
+	}
+</switch>
+@if (!string.IsNullOrWhiteSpace(errorResult))
 {
-	<p>Expected exception encountered: '@ex.Message'.</p>
+	<p>@errorResult</p>
 }
 
-
 <h2>Test 4</h2>
 
-@try
-{
-	<switch expression="2">
+@{ errorResult = null; }
+<switch expression="3">
+	@try
+	{
 		<case value="1"><p>Should not display 1.</p></case>
 		<case value="2"><p>Should not display 2.</p></case>
 		<default><p>Should not display 3.</p></default>
 		<default><p>Should not display 4.</p></default>
-	</switch>
-}
-catch (LogicTagHelperException ex)
+	}
+	catch (LogicTagHelperException ex)
+	{
+		errorResult = $"Expected exception encountered: '{ex.Message}'.";
+	}
+</switch>
+@if (!string.IsNullOrWhiteSpace(errorResult))
 {
-	<p>Expected exception encountered: '@ex.Message'.</p>
+	<p>@errorResult</p>
 }
 
 <h2>Test 5</h2>
 
-@try
-{
+@{
 	var stringVal = "some string";
-	<switch expression="2">
+	var result = string.Empty;
+}
+<switch expression="2">
+	@try
+	{
 		<case value="1"><p>Should not display 1.</p></case>
 		<case value="@stringVal"><p>Should not display 2.</p></case>
-	</switch>
-}
-catch (LogicTagHelperException ex)
-{
-	<p>Expected exception encountered: '@ex.Message'.</p>
-}
+	}
+	catch (LogicTagHelperException ex)
+	{
+		result = $"Expected exception encountered: {ex.Message}.";
+	}
+</switch>
+<p>@result</p>
+
+<h2>Test 6</h2>
+
+@{ result = string.Empty; }
+<switch>
+	@try
+	{
+		<case value="1"><p>Should not display.</p></case>
+	}
+	catch (LogicTagHelperException ex)
+	{
+		result = $"Expected exception encountered: {ex.Message}.";
+	}
+</switch>
+<p>@result</p>
+
+<h2>Test 7</h2>
+
+@{ result = string.Empty; }
+<switch>
+	@try
+	{
+		<default><p>Should not display.</p></default>
+	}
+	catch (LogicTagHelperException ex)
+	{
+		result = $"Expected exception encountered: {ex.Message}.";
+	}
+</switch>
+<p>@result</p>

LogicTagHelpers.Demo/Views/Home/TestWhile.cshtml

@@ -0,0 +1,20 @@
+<h2>Test 1</h2>
+
+@{ var x = 0; }
+<while condition="() => x < 10">
+	<p>Should display @x.</p>
+	@{ x++; }
+</while>
+
+<h2>Test 2</h2>
+
+@try
+{
+	<while>
+		<p>Should not display.</p>
+	</while>
+}
+catch (Exception ex)
+{
+	<p>Expected exception occurred: '@ex.Message'.</p>
+}

LogicTagHelpers.Tests/CreateClassTests.cs

@@ -74,5 +74,15 @@ public void CanCreateForeachTagHelper()
 			// Assert
 			Assert.IsNotNull(result);
 		}
+
+		[TestMethod]
+		public void CanCreateWhileTagHelper()
+		{
+			// Act
+			var result = new WhileTagHelper();
+
+			// Assert
+			Assert.IsNotNull(result);
+		}
 	}
 }

LogicTagHelpers/CaseTagHelper.cs

@@ -15,6 +15,11 @@ public override async Task ProcessAsync(TagHelperContext context, TagHelperOutpu
 		{
 			var switchContext = (SwitchContext) context.Items[SwitchContext.ContextKey];
 
+			if (switchContext == null)
+			{
+				throw new LogicTagHelperException("Case statement inside of switch with no valid expression.");
+			}
+
 			if (Value.GetType() != switchContext.Expression.GetType())
 			{
 				throw new LogicTagHelperException(

LogicTagHelpers/DefaultTagHelper.cs

@@ -12,7 +12,11 @@ public class DefaultTagHelper : TagHelper
 		public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
 		{
 			var switchContext = (SwitchContext) context.Items[SwitchContext.ContextKey];
-
+
+			if (switchContext == null)
+			{
+				throw new LogicTagHelperException("Default statement inside of switch with no valid expression.");
+			}
 
 			if (switchContext.HasDefault)
 			{

LogicTagHelpers/LogicTagHelpers.csproj

@@ -3,7 +3,7 @@
   <PropertyGroup>
     <TargetFramework>netstandard2.0</TargetFramework>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
-    <Version>0.3.0</Version>
+    <Version>0.4.0</Version>
     <Authors>Delbert Matlock</Authors>
     <Company>Stuff Of Interest</Company>
     <Product />
@@ -13,9 +13,9 @@ Done:
 * if/then/else
 * switch/case/default
 * foreach
+* while
 
 Future:
-* while
 * for
 * do</Description>
     <PackageProjectUrl>https://github.com/StuffOfInterest/LogicTagHelpers</PackageProjectUrl>

LogicTagHelpers/SwitchTagHelper.cs

@@ -6,7 +6,7 @@ namespace LogicTagHelpers
 	/// <summary>
 	/// Include at most one section based on value of an expression.
 	/// </summary>
-	[HtmlTargetElement("switch")]
+	[HtmlTargetElement("switch", Attributes = "expression")]
 	[RestrictChildren("case", "default")]
 	public class SwitchTagHelper : TagHelper
 	{

LogicTagHelpers/WhileTagHelper.cs

@@ -0,0 +1,35 @@
+using System;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Razor.TagHelpers;
+
+namespace LogicTagHelpers
+{
+	/// <summary>
+	/// Re-render block of code as long as condition evaluates to true.
+	/// </summary>
+	public class WhileTagHelper : TagHelper
+	{
+		/// <summary>
+		/// Function to evaluate exit condition.
+		/// Inner content will render as long as the condition returns true.
+		/// </summary>
+		public Func<bool> Condition { get; set; }
+
+		public override async Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
+		{
+			if (Condition == null)
+			{
+				throw new LogicTagHelperException("Condition may not be null.");
+			}
+
+			output.TagName = null;
+			output.Content.Clear();
+
+			while (Condition.Invoke())
+			{
+				var childContent = await output.GetChildContentAsync(false);
+				output.Content.AppendHtml(childContent);
+			}
+		}
+	}
+}

README.md

@@ -12,10 +12,10 @@
 * [switch](#switch)
   * case
 * [foreach](#foreach)
+* [while](#while)
 
 ## Future Tags
 
-* while
 * for
 * do
 
@@ -61,4 +61,14 @@ Following line must be added to the `_ViewImports.cshtml` file for the logic tag
 <foreach iterator="context">
    (content to display for each item in collection)
 </foreach>
+```
+
+### while
+
+```cshtml
+@{ var x = 0; }
+<while condition="() => x < 10">
+	(content to display while condition is true)
+	@{ x++; }
+</while>
 ```