Added null guard to AddClassFromAttributes fixes #12

Author: EdCharbeneau

BlazorComponentUtilities.Tests/CssBuilderTests.cs

@@ -133,6 +133,23 @@ public void ShouldNotThrowWhenNullFor_BuildClassesFromAttributes()
             }
         }
 
+        [Fact]
+        public void ShouldNotThrowWhenNullForAttributeItem_BuildClassesFromAttributes()
+        {
+            {
+                //arrange
+                // Simulates Razor Components attribute splatting feature
+                IReadOnlyDictionary<string, object> attributes = new Dictionary<string, object> { { "class", null } };
+
+                //act
+                var ClassToRender = new CssBuilder("item-one")
+                                .AddClassFromAttributes(attributes)
+                                .Build();
+                //assert
+                ClassToRender.Should().Be("item-one");
+            }
+        }
+
         [Fact]
         public void ForceNullForWhitespace_BuildClassesFromAttributes()
         {

BlazorComponentUtilities/BlazorComponentUtilities.csproj

@@ -15,12 +15,15 @@
     <Authors>Ed Charbeneau</Authors>
     <Company>BlazorPro</Company>
     <Product>BlazorComponentUtilities CssBuilder</Product>
-    <PackageReleaseNotes>1.7.1
-    Fixed trivial performance issue with redundant assignment when building strings
-1.7.0
-    Added SetPrefix method to reduce reptititive class prefixing
-1.6.0
-      Added Func&lt;string&gt; value overload for ValueBuilder
+    <PackageReleaseNotes>
+		1.8.0
+		Fixed null ref error when using AddClassFromAttributes and passing a null attribute value.
+		1.7.1
+		Fixed trivial performance issue with redundant assignment when building strings
+		1.7.0
+		Added SetPrefix method to reduce reptititive class prefixing
+		1.6.0
+		Added Func&lt;string&gt; value overload for ValueBuilder
 1.5.0
       Added Func&lt;string&gt; value overload for StyleBuilder
       Minor performance improvements for .Add*Attributes
@@ -32,10 +35,10 @@
       Added utility method for returning null for empty strings. This is useful for splatting scenarios.
       Added utility method for starting off new builders.
 </PackageReleaseNotes>
-    <Version>1.7.1</Version>
+    <Version>1.8.0</Version>
     <PackageIcon>blazor-glove-256.jpg</PackageIcon>
-    <AssemblyVersion>1.7.1.0</AssemblyVersion>
-    <FileVersion>1.7.1.0</FileVersion>
+    <AssemblyVersion>1.8.0.0</AssemblyVersion>
+    <FileVersion>1.8.0.0</FileVersion>
   </PropertyGroup>
 
   <ItemGroup>

BlazorComponentUtilities/CssBuilder.cs

@@ -117,7 +117,7 @@ public CssBuilder AddValue(string value)
         /// <returns>CssBuilder</returns>
         public CssBuilder AddClassFromAttributes(IReadOnlyDictionary<string, object> additionalAttributes) =>
             additionalAttributes == null ? this :
-            additionalAttributes.TryGetValue("class", out var c) ? AddClass(c.ToString()) : this;
+            additionalAttributes.TryGetValue("class", out var c) && c != null ? AddClass(c.ToString()) : this;
 
         /// <summary>
         /// Finalize the completed CSS Classes as a string.