如何在C#中使用JsonWriter序列化嵌套集合 [英] howto Serialize a Nested collection using JsonWriter in C#

问题描述

我需要产生与使用JSON在XML中产生的输出相同的输出

对于Excel工作表中的某些表格数据，数据的格式为:

  Column1 Column2 Column3AAA bbb cccXXX YYY ZZZkkk jjj nnn 

我需要使用Json Writer编写Json文件，因为我无法创建一个类来生成数据，但是我必须使用创建的JSON将其反序列化为另一个应用程序中的类.为了能够在消费类应用程序中反序列化该类，我需要一个可以将其命名为MyClass的类，该类包含一个Items集合，每个Item代表一个Row，标题，Column1，Column2，Column3是属性的名称./p>

我已经能够制作出这个:

  {物品": {"Column1":"AAA"，"Column2":"BBB"，"Column3":"CCC"，}，物品": {"Column1":"XXX"，"Column2":"YYY"，"Column3":"ZZZ"，}，} 

不幸的是，这不是包含Item集合的对象，因此它不会反序列化.

这是我用于从excel文件进​​行手动序列化的代码，我找不到的是如何对集合的开始和结束进行脚本编写:

  StringBuilder sb = new StringBuilder();StringWriter sw =新的StringWriter(sb);JsonWriter jsonWriter = null;jsonWriter =新的JsonTextWriter(sw);jsonWriter.Formatting = Newtonsoft.Json.Formatting.Indented;jsonWriter.WriteStartObject();int countAwait = 0;//在这里我想写什么来打开收藏集对于(int row = firstRow; row< = end.Row; row ++){数++;countAwait ++;如果(countAwait> = 10){ResultText =读取记录" +计数；countAwait = 0;}jsonWriter.WritePropertyName(RowElement);jsonWriter.WriteStartObject();对于(int col = start.Column; col< = end.Column; col ++){jsonWriter.WritePropertyName(fieldNames [col]);jsonWriter.WriteValue(GetCellStringValue(ws，row，col));}jsonWriter.WriteEndObject();}//在这里，我需要编写集合的结尾jsonWriter.WriteEndObject();jsonWriter.Close(); 

进行编辑以添加Json Serializer如何序列化我的目标类的示例:

  {项目": [{"Column1":"XXX"，"Column2":"YYY"，"Column3":"ZZZ"，}，{"Column1":"AAA"，"Column2":"BBB"，"Column3":"CCC"，}]} 

该类为MyClass，并且包含Item类型的Classes的集合.

解决方案

您应该只写一次属性名称"Items" ，然后使用

(这里我假设 RowElement 与"Items" 字符串相对应.)

I need to produce the same output I produce in XML using JSON

For some tabular data that is in an Excel Worksheet, data is in the format:

Column1 Column2 Column3
AAA      bbb     ccc
XXX      YYY     ZZZ
kkk      jjj     nnn

I need to write the Json file Using the Json Writer because I can't create a class to produce the data, but I have then to use the created JSON deserializing it as a class in a different application. To be able to deserialize the class in the consumer application I need to have a class we can name it MyClass containing a collection of Items, each Item representing a Row, the headers, Column1, Column2, Column3 are the names of the properties.

I've been able to produce this:

{
  "Item": {
    "Column1": "AAA",
    "Column2": "BBB",
    "Column3": "CCC",
  },
  "Item": {
    "Column1": "XXX",
    "Column2": "YYY",
    "Column3": "ZZZ",
  },
 }

Unfortunately this is not an object containing a collection of Item so It does not deserialize.

This is the code I use for the manual serialization from the excel file, what I was not able to find is how to script the start and end of the collection:

StringBuilder sb = new StringBuilder();
StringWriter sw = new StringWriter(sb);
JsonWriter jsonWriter = null;
jsonWriter = new JsonTextWriter(sw);


jsonWriter.Formatting = Newtonsoft.Json.Formatting.Indented;
jsonWriter.WriteStartObject();
int countAwait = 0;
// Here I miss what to write to open the collection
for (int row = firstRow; row <= end.Row; row++)
{
    count++;
    countAwait++;
    if (countAwait >= 10)
    {
        ResultText = "Reading record " + count;
        countAwait = 0;
    }
    jsonWriter.WritePropertyName(RowElement);
    jsonWriter.WriteStartObject();
    for (int col = start.Column; col <= end.Column; col++)
    {
        jsonWriter.WritePropertyName(fieldNames[col]);
        jsonWriter.WriteValue(GetCellStringValue(ws, row, col));

    }
    jsonWriter.WriteEndObject();
}
// Here I need to write the closing of the collection

jsonWriter.WriteEndObject();
jsonWriter.Close();

Edited to add how the Json Serializer serializes a sample of my destination class:

{
  "Items": [
    {
      "Column1": "XXX",
      "Column2": "YYY",
      "Column3": "ZZZ",
    },
    {
      "Column1": "AAA",
      "Column2": "BBB",
      "Column3": "CCC",
    }
  ]
}

The class is MyClass and Contains a collection Items of Classes of type Item.

解决方案

You should write the property name "Items" only once, then for its value use JsonWriter.WriteStartArray() and JsonWriter.WriteEndArray() to start and end a JSON array, then write each row as an object nested in the array:

var sb = new StringBuilder();
using (var sw = new StringWriter(sb))
using (var jsonWriter = new JsonTextWriter(sw))
{
    var countAwait = 0;

    jsonWriter.Formatting = Newtonsoft.Json.Formatting.Indented;
    jsonWriter.WriteStartObject(); // Write the opening of the root object
    jsonWriter.WritePropertyName(RowElement); // Write the "Items" property name
    jsonWriter.WriteStartArray(); // Write the opening of the "Items" array

    for (int row = firstRow; row <= end.Row; row++)
    {
        count++;
        countAwait++;
        if (countAwait >= 10)
        {
            ResultText = "Reading record " + count;
            countAwait = 0;
        }
        jsonWriter.WriteStartObject(); // Write the beginning of an entry in the "Items" array
        for (int col = start.Column; col <= end.Column; col++)
        {
            jsonWriter.WritePropertyName(fieldNames[col]);
            jsonWriter.WriteValue(GetCellStringValue(ws, row, col));

        }
        jsonWriter.WriteEndObject(); // Write the ending of an entry in the "Items" array
    }

    jsonWriter.WriteEndArray(); // Write the closing of the "Items" array.
    jsonWriter.WriteEndObject(); // Write the closing of the root object
    // No need to close explicitly when inside a using statement
}

(Here I am assuming that RowElement corresponds to the "Items" string.)

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