/// <summary>
/// Returns syntax for initializing a new instance of the provided type.
/// </summary>
/// <param name="type">The type.</param>
/// <returns>Syntax for initializing a new instance of the provided type.</returns>
private static ExpressionSyntax GetObjectCreationExpressionSyntax(Type type)
{
ExpressionSyntax result;
var typeInfo = type.GetTypeInfo();
if (typeInfo.IsValueType)
{
// Use the default value.
result = SF.DefaultExpression(typeInfo.GetTypeSyntax());
}
else if (type.GetConstructor(Type.EmptyTypes) != null)
{
// Use the default constructor.
result = SF.ObjectCreationExpression(typeInfo.GetTypeSyntax()).AddArgumentListArguments();
}
else
{
// Create an unformatted object.
#if DNXCORE50
var bindingFlags = SyntaxFactoryExtensions.GetBindingFlagsParenthesizedExpressionSyntax(
SyntaxKind.BitwiseOrExpression,
BindingFlags.Instance,
BindingFlags.NonPublic,
BindingFlags.Public);
var nullLiteralExpressionArgument = SF.Argument(SF.LiteralExpression(SyntaxKind.NullLiteralExpression));
var typeArg = SF.Argument(SF.TypeOfExpression(typeInfo.GetTypeSyntax()));
var bindingFlagsArg = SF.Argument(bindingFlags);
var binderArg = nullLiteralExpressionArgument;
ArgumentSyntax ctorArgumentsArg;
var cons = typeInfo.GetConstructors(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance)
.OrderBy(p => p.GetParameters().Count()).FirstOrDefault();
var consParameters = cons != null?cons.GetParameters().Select(p => p.ParameterType).ToArray() : null;
if (consParameters != null && consParameters.Length > 0)
{
var separatedSyntaxList = new SeparatedSyntaxList <ExpressionSyntax>();
separatedSyntaxList = consParameters
.Aggregate(separatedSyntaxList, (current, t) => current.Add(SF.DefaultExpression(t.GetTypeInfo().GetTypeSyntax())));
ctorArgumentsArg = SF.Argument(separatedSyntaxList.GetArrayCreationWithInitializerSyntax(
SF.PredefinedType(SF.Token(SyntaxKind.ObjectKeyword))));
}
else
{
ctorArgumentsArg = nullLiteralExpressionArgument;
}
var cultureInfoArg = SF.Argument(
SF.IdentifierName("System").Member("Globalization").Member("CultureInfo").Member("InvariantCulture"));
var createInstanceArguments = new []
{
typeArg,
bindingFlagsArg,
binderArg,
ctorArgumentsArg,
cultureInfoArg
};
Expression <Func <object> > getUninitializedObject = () => Activator.CreateInstance(
default(Type),
BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public,
null,
null,
System.Globalization.CultureInfo.InvariantCulture);
result = SF.CastExpression(
type.GetTypeSyntax(),
getUninitializedObject.Invoke()
.AddArgumentListArguments(createInstanceArguments));
#else
Expression <Func <object> > getUninitializedObject =
() => FormatterServices.GetUninitializedObject(default(Type));
result = SF.CastExpression(
type.GetTypeSyntax(),
getUninitializedObject.Invoke()
.AddArgumentListArguments(
SF.Argument(SF.TypeOfExpression(typeInfo.GetTypeSyntax()))));
#endif
}
return(result);
}