如果类没有空构造函数，则JSON.NET无法序列化

Question

我有一个自定义类，该类具有来自外部dll的某些属性（我无法更改此DLL类）

如果属性的类有一个空的构造器，则该属性已序列化，但是如果只有一个构造器必须给出参数，则它无法序列化。

例如，我从此类创建了一个实例，并尝试序列化，结果是" []"

这是类

public class Shape : ShapeBase,    
{
 public Shape(DocumentBase doc, ShapeType shapeType);    
 public Chart Chart { get; }
 public bool ExtrusionEnabled { get; }
 public Fill Fill { get; }
 public Color FillColor { get; set; }
 public bool Filled { get; set; }
 public Paragraph FirstParagraph { get; }
 public bool HasChart { get; }
 public bool HasImage { get; }
 public ImageData ImageData { get; }
 public Paragraph LastParagraph { get; }
 public override NodeType NodeType { get; }
 public OleFormat OleFormat { get; }
 public bool ShadowEnabled { get; }
 public SignatureLine SignatureLine { get; }
 public StoryType StoryType { get; }
 public Stroke Stroke { get; }
 public Color StrokeColor { get; set; }
 public bool Stroked { get; set; }
 public double StrokeWeight { get; set; }
 public TextBox TextBox { get; }
 public TextPath TextPath { get; }
 public override bool Accept(DocumentVisitor visitor);
}

我尝试像那样序列化

    Shape shape = new Shape(_wordDocument, ShapeType.TextPlainText);
    string json = JsonConvert.SerializeObject(shape, Formatting.Indented);

，但其他班级就像

public class PdfSaveOptions : FixedPageSaveOptions
{
    public PdfSaveOptions();
    public int BookmarksOutlineLevel { get; set; }
    public PdfCompliance Compliance { get; set; }
    public bool CreateNoteHyperlinks { get; set; }
    public PdfCustomPropertiesExport CustomPropertiesExport { get; set; }
    public PdfDigitalSignatureDetails DigitalSignatureDetails { get; set; }
    public override DmlEffectsRenderingMode DmlEffectsRenderingMode { get; set; }
    public bool DownsampleImages { get; set; }
    public DownsampleOptions DownsampleOptions { get; }
    .......
}

它已序列化。

所以我还尝试使用一些选项，例如

 ConstructorHandling = ConstructorHandling.AllowNonPublicDefaultConstructor

但不起作用。

Answer 1

您仍然需要具有无参数的constructor。否则Deserialize方法将无法创建该对象的实例。Deserialize尝试实例化对象，然后使用Properties或Fields（取决于配置）将数据设置为其。

，只要无参数，就可以制作构造函数private或internal。然后，您有一种构造函数不存在于班级外。

public class Shape : ShapeBase,    
{
 private Shape() {
   //here some inits
 }
 public Shape(DocumentBase doc, ShapeType shapeType);    
 public Chart Chart { get; }
 public bool ExtrusionEnabled { get; }
 public Fill Fill { get; }
 public Color FillColor { get; set; }
 public bool Filled { get; set; }
 public Paragraph FirstParagraph { get; }
 public bool HasChart { get; }
 public bool HasImage { get; }
 public ImageData ImageData { get; }
 public Paragraph LastParagraph { get; }
 public override NodeType NodeType { get; }
 public OleFormat OleFormat { get; }
 public bool ShadowEnabled { get; }
 public SignatureLine SignatureLine { get; }
 public StoryType StoryType { get; }
 public Stroke Stroke { get; }
 public Color StrokeColor { get; set; }
 public bool Stroked { get; set; }
 public double StrokeWeight { get; set; }
 public TextBox TextBox { get; }
 public TextPath TextPath { get; }
 public override bool Accept(DocumentVisitor visitor);
}