Add configuration option to serialize empty collections (fixes #490)

XmlSchemaClassGenerator.Console/Program.cs

@@ -65,6 +65,7 @@ static int Main(string[] args)
  var nameSubstituteFiles = new List<string>();
  var unionCommonType = false;
  var separateNamespaceHierarchy = false;
+ var serializeEmptyCollections = false;
 
  var options = new OptionSet {
  { "h|help", "show this message and exit", v => showHelp = v != null },
@@ -158,6 +159,7 @@ A file name may be given by appending a pipe sign (|) followed by a file name (l
  { "es|enumAsString", "Use string instead of enum for enumeration", v => enumAsString = v != null },
  { "ca|commandArgs", "generate a comment with the exact command line arguments that were used to generate the source code (default is true)", v => generateCommandLineArgs = v != null },
  { "uc|unionCommonType", "generate a common type for unions if possible (default is false)", v => unionCommonType = v != null },
+ { "ec|serializeEmptyCollections", "serialize empty collections (default is false)", v => serializeEmptyCollections = v != null },
  };
 
  var globsAndUris = options.Parse(args);
@@ -244,7 +246,8 @@ A file name may be given by appending a pipe sign (|) followed by a file name (l
  UseArrayItemAttribute = useArrayItemAttribute,
  EnumAsString = enumAsString,
  MapUnionToWidestCommonType = unionCommonType,
- SeparateNamespaceHierarchy = separateNamespaceHierarchy
+ SeparateNamespaceHierarchy = separateNamespaceHierarchy,
+ SerializeEmptyCollections = serializeEmptyCollections,
  };
 
  if (nameSubstituteMap.Any())

XmlSchemaClassGenerator.Tests/XmlTests.cs

@@ -614,6 +614,38 @@ public void TestArray()
  SharedTestFunctions.TestSamples(Output, "Tableau.Array", TableauPattern);
  }
 
+ [Fact, TestPriority(1)]
+ [UseCulture("en-US")]
+ public void TestSerializeEmptyCollection()
+ {
+ var output = new FileWatcherOutputWriter(Path.Combine("output", "Tableau.EmptyCollection"));
+ Compiler.Generate("Tableau.EmptyCollection", TableauPattern,
+ new Generator
+ {
+ OutputWriter = output,
+ EnableDataBinding = true,
+ CollectionSettersMode = CollectionSettersMode.Private,
+ SerializeEmptyCollections = true
+ });
+ SharedTestFunctions.TestSamples(Output, "Tableau.EmptyCollection", TableauPattern);
+ }
+
+ [Fact, TestPriority(1)]
+ [UseCulture("en-US")]
+ public void TestSerializeEmptyPublicCollection()
+ {
+ var output = new FileWatcherOutputWriter(Path.Combine("output", "Tableau.EmptyPublicCollection"));
+ Compiler.Generate("Tableau.EmptyPublicCollection", TableauPattern,
+ new Generator
+ {
+ OutputWriter = output,
+ EnableDataBinding = true,
+ CollectionSettersMode = CollectionSettersMode.Public,
+ SerializeEmptyCollections = true
+ });
+ SharedTestFunctions.TestSamples(Output, "Tableau.EmptyPublicCollection", TableauPattern);
+ }
+
  [Fact, TestPriority(1)]
  [UseCulture("en-US")]
  public void TestDtsx()

XmlSchemaClassGenerator/Generator.cs

@@ -336,6 +336,12 @@ public bool SeparateNamespaceHierarchy
  set { _configuration.SeparateNamespaceHierarchy = value; }
  }
 
+ public bool SerializeEmptyCollections
+ {
+ get { return _configuration.SerializeEmptyCollections; }
+ set { _configuration.SerializeEmptyCollections = value; }
+ }
+
  public bool ValidationError { get; private set; }
 
  static Generator()

XmlSchemaClassGenerator/GeneratorConfiguration.cs

@@ -343,5 +343,10 @@ public void WriteLog(string message)
  /// Separates namespace hierarchy by folder. Default is false.
  /// </summary>
  public bool SeparateNamespaceHierarchy { get; set; } = false;
+
+ /// <summary>
+ /// Determines whether empty collections should be serialized as empty elements. Default is false.
+ /// </summary>
+ public bool SerializeEmptyCollections { get; set; } = false;
  }
 }

XmlSchemaClassGenerator/TypeModel.cs

@@ -869,56 +869,65 @@ [new CodeMethodReturnStatement(valueExpression)],
  }
  else if (isEnumerable && !IsRequired)
  {
- var listReference = new CodePropertyReferenceExpression(new CodeThisReferenceExpression(), Name);
- var collectionType = Configuration.CollectionImplementationType ?? Configuration.CollectionType;
- var countProperty = collectionType == typeof(Array) ? nameof(Array.Length) : nameof(List<int>.Count);
- var countReference = new CodePropertyReferenceExpression(listReference, countProperty);
- var notZeroExpression = new CodeBinaryOperatorExpression(countReference, CodeBinaryOperatorType.IdentityInequality, new CodePrimitiveExpression(0));
- if (Configuration.CollectionSettersMode is CollectionSettersMode.PublicWithoutConstructorInitialization or CollectionSettersMode.Public or CollectionSettersMode.Init or CollectionSettersMode.InitWithoutConstructorInitialization)
- {
- var notNullExpression = new CodeBinaryOperatorExpression(listReference, CodeBinaryOperatorType.IdentityInequality, new CodePrimitiveExpression(null));
- notZeroExpression = new CodeBinaryOperatorExpression(notNullExpression, CodeBinaryOperatorType.BooleanAnd, notZeroExpression);
- }
- var returnStatement = new CodeMethodReturnStatement(notZeroExpression);
+ var canBeNull = Configuration.CollectionSettersMode is CollectionSettersMode.PublicWithoutConstructorInitialization or CollectionSettersMode.Public or CollectionSettersMode.Init or CollectionSettersMode.InitWithoutConstructorInitialization;
 
- if (Configuration.UseShouldSerializePattern)
+ if (canBeNull || !Configuration.SerializeEmptyCollections)
  {
- var shouldSerializeMethod = new CodeMemberMethod
+ var listReference = new CodePropertyReferenceExpression(new CodeThisReferenceExpression(), Name);
+ var collectionType = Configuration.CollectionImplementationType ?? Configuration.CollectionType;
+ var countProperty = collectionType == typeof(Array) ? nameof(Array.Length) : nameof(List<int>.Count);
+ var countReference = new CodePropertyReferenceExpression(listReference, countProperty);
+ var notZeroExpression = new CodeBinaryOperatorExpression(countReference, CodeBinaryOperatorType.IdentityInequality, new CodePrimitiveExpression(0));
+ var returnExpression = notZeroExpression;
+
+ if (canBeNull)
  {
- Attributes = MemberAttributes.Public,
- Name = "ShouldSerialize" + Name,
- ReturnType = new CodeTypeReference(typeof(bool)),
- Statements = { returnStatement }
- };
+ var notNullExpression = new CodeBinaryOperatorExpression(listReference, CodeBinaryOperatorType.IdentityInequality, new CodePrimitiveExpression(null));
+ var notNullOrEmptyExpression = new CodeBinaryOperatorExpression(notNullExpression, CodeBinaryOperatorType.BooleanAnd, notZeroExpression);
+ returnExpression = Configuration.SerializeEmptyCollections ? notNullExpression : notNullOrEmptyExpression;
+ }
 
- Configuration.MemberVisitor(shouldSerializeMethod, this);
+ var returnStatement = new CodeMethodReturnStatement(returnExpression);
 
- typeDeclaration.Members.Add(shouldSerializeMethod);
- }
- else
- {
- var specifiedProperty = new CodeMemberProperty
+ if (Configuration.UseShouldSerializePattern)
  {
- Type = TypeRef<bool>(),
- Name = Name + Specified,
- HasSet = false,
- HasGet = true,
- };
- specifiedProperty.CustomAttributes.Add(ignoreAttribute);
- if (Configuration.EntityFramework) { specifiedProperty.CustomAttributes.Add(notMappedAttribute); }
- specifiedProperty.Attributes = MemberAttributes.Public | MemberAttributes.Final;
+ var shouldSerializeMethod = new CodeMemberMethod
+ {
+ Attributes = MemberAttributes.Public,
+ Name = "ShouldSerialize" + Name,
+ ReturnType = new CodeTypeReference(typeof(bool)),
+ Statements = { returnStatement }
+ };
 
- specifiedProperty.GetStatements.Add(returnStatement);
+  Configuration.MemberVisitor(shouldSerializeMethod, this);
 
- var specifiedDocs = new DocumentationModel[] {
+ typeDeclaration.Members.Add(shouldSerializeMethod);
+ }
+ else
+ {
+ var specifiedProperty = new CodeMemberProperty
+ {
+ Type = TypeRef<bool>(),
+ Name = Name + Specified,
+ HasSet = false,
+ HasGet = true,
+ };
+ specifiedProperty.CustomAttributes.Add(ignoreAttribute);
+ if (Configuration.EntityFramework) { specifiedProperty.CustomAttributes.Add(notMappedAttribute); }
+ specifiedProperty.Attributes = MemberAttributes.Public | MemberAttributes.Final;
+
+ specifiedProperty.GetStatements.Add(returnStatement);
+
+ var specifiedDocs = new DocumentationModel[] {
  new() { Language = English, Text = $"Gets a value indicating whether the {Name} collection is empty." },
  new() { Language = German, Text = $"Ruft einen Wert ab, der angibt, ob die {Name}-Collection leer ist." }
  };
- specifiedProperty.Comments.AddRange(GetComments(specifiedDocs).ToArray());
+  specifiedProperty.Comments.AddRange(GetComments(specifiedDocs).ToArray());
 
- Configuration.MemberVisitor(specifiedProperty, this);
+  Configuration.MemberVisitor(specifiedProperty, this);
 
- typeDeclaration.Members.Add(specifiedProperty);
+ typeDeclaration.Members.Add(specifiedProperty);
+ }
  }
  }