如何从数据表或数据集创建嵌套XML而无需循环？ [英] How to create nested XML from datatable or dataset without looping?

问题描述

我想从DataTable创建无循环的嵌套XML。

I want to create nested XML from DataTable without loop.

数据表：员工

我尝试了以下代码段

DataSet ds=new DataSet ("EmployeeDetails");
DataTable dtConvert = datatable to be converted
ds.Tables.Add(dtConvert);
ds.WriteXml("sample.txt");

并获得了如下所示的XML，

and got the XML which looks like,

<EmployeeDetails>
  <Employee>
    <name>John</name>
    <city>chennai</city>
    <state>Tamilnadu</state>
    <country>India</country>
  </Employee>
  <Employee>
    <name>David</name>
    <city>Bangalore</city>
    <state>Karnataka</state>
    <country>India</country>
  </Employee>
</EmployeeDetails>

但是我想要的XML格式是

But the XML format I want is

<EmployeeDetails>
  <Employee>
    <name>John</name>
    <address>
        <city>chennai</city>
        <state>Tamilnadu</state>
        <country>India</country>
    </address>
  </Employee>
  <Employee>
    <name>David</name>
    <address>
        <city>Bangalore</city>
        <state>Karnataka</state>
        <country>India</country>
    </address>
  </Employee>
</EmployeeDetails>

有人可以指导我以最佳方式做到这一点吗？

Can anyone please guide me to do this in a best way?

推荐答案

        DataSet ds = new DataSet("EmployeeList");

        //create table address
        DataTable address = new DataTable("Address");
        DataColumn column;

        //add column id
        column = new DataColumn();
        column.DataType = System.Type.GetType("System.Int32");
        column.ColumnName  = "ID";
        address.Columns.Add(column);
        //address.PrimaryKey = new DataColumn[1] { column };

        //add column City
        column = new DataColumn();
        column.DataType = System.Type.GetType("System.String");
        column.ColumnName = "City";
        address.Columns.Add(column);

        //add column State
        column = new DataColumn();
        column.DataType = System.Type.GetType("System.String");
        column.ColumnName = "State";
        address.Columns.Add(column);

        //add column Country
        column = new DataColumn();
        column.DataType = System.Type.GetType("System.String");
        column.ColumnName = "Country";
        address.Columns.Add(column);

        ds.Tables.Add(address); //add table address to dataset

        //create table employee
        DataTable employee = new DataTable("Employee");

        //add column ID
        column = new DataColumn();
        column.DataType = System.Type.GetType("System.Int32");
        column.ColumnName = "ID";
        employee.Columns.Add(column);
        employee.PrimaryKey = new DataColumn[1] { column };

        //add column Name
        column = new DataColumn();
        column.DataType = System.Type.GetType("System.String");
        column.ColumnName = "Name";
        employee.Columns.Add(column);

        //add column Address
        //column = new DataColumn();
        //column.DataType = System.Type.GetType("System.Int32");
        //column.ColumnName = "Address";
        //employee.Columns.Add(column);

        ds.Tables.Add(employee); //add table employee to dataset

        //set foreign key constraint
        //ForeignKeyConstraint fk = new ForeignKeyConstraint("AddressFK", 
        //ds.Tables["Address"].Columns["ID"], ds.Tables["Employee"].Columns["Address"]);

        //fk.DeleteRule = Rule.None;
        //ds.Tables["Employee"].Constraints.Add(fk);

        //
        // fill data to data set
        //
        DataRow row;
        row = address.NewRow();
        row["ID"] = 1;
        row["City"] = "test";
        row["State"] = "test";
        row["Country"] = "test";

        address.Rows.Add(row);

        row = employee.NewRow();
        row["Name"] = "abc";
        row["ID"] = 1;
        //row["Address"] = 1;

        employee.Rows.Add(row);

        DataRelation relation = ds.Relations.Add("relation", ds.Tables["Employee"].Columns["ID"], ds.Tables["Address"].Columns["ID"]);
        relation.Nested = true;

        ds.WriteXml("test.txt"); //create xml from dataset

创建xml

我在这里要做的是创建2个表雇员和地址。 地址有4列 ID -引用 Employee 主键，州，城市，国家。 Employee 有2列 Name ， ID -主键。然后将这些表添加到数据集 ds 。最后，从 ds 创建xml。

What I'm trying to do here is creating 2 tables Employee and Address. Address has 4 columns ID - foreign key that refer to Employee primary key, State, City, Country. Employee has 2 columns Name, ID - primary key. Then add those tables to dataset ds. Finally, create xml from ds.

P / S：我用纯文本形式编写（不使用IDE，因为这台计算机没有任何IDE :(，因此，如果拼写错误或语法错误，请让我知道）

P/S: I write this in pure text (without using IDE because this computer doesn't has any IDE :(, so if any error on typo or syntax, please let me know)

更新我更新了代码，现在结果XML如下所示：

UPDATE I updated the code, now the result XML will look like this:

<?xml version="1.0" standalone="yes"?>
<EmployeeList>
  <Employee>
    <ID>1</ID>
    <Name>abc</Name>
    <Address>
      <ID>1</ID>
      <City>test</City>
      <State>test</State>
      <Country>test</Country>
    </Address>
  </Employee>
</EmployeeList>

我从上一次的关系中弄错了时间，它应该是 address 地址中的外键，它引用 employee 主键（在这种情况下，我是用户列 ID ）

I made a mistake with the relationship from last time, it should be a foreign key in address that refer to employee primary key (in this case, I user column ID)

UPDATE2 以从地址中排除ID，请在调用 ds.WriteXML（ test.xml）

UPDATE2 to exclude ID from Address, add this line right before you call ds.WriteXML("test.xml")

ds.Tables["Address"].Columns["ID"].ColumnMapping = MappingType.Hidden;

您还可以添加以下行以从员工中排除ID：

You can also add following line to exclude ID from employee as well:

ds.Tables["Employee"].Columns["ID"].ColumnMapping = MappingType.Hidden;

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