如何在不循環的情況下從數據表或數據集創建嵌套XML？

Question

我想在沒有循環的情況下從DataTable創建嵌套XML。

DataTable：員工

我曾嘗試過以下代碼段

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

並得到了看起來像的XML，

<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>

但我想要的XML格式是

<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>

誰能指導我以最好的方式做到這一點？

Answer 1

        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

我在這里要做的是創建2個表Employee和Address 。 Address有4列ID - 指向Employee主鍵， State ， City ， Country外鍵。 Employee有2列Name ， ID - 主鍵。 然后將這些表添加到數據集ds 。 最后，從ds創建xml。

P / S：我用純文本寫這個（不使用IDE，因為這台計算機沒有任何IDE :(，如果有任何關於拼寫錯誤或語法的錯誤，請告訴我）

更新我更新了代碼，現在結果XML將如下所示：

<?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>

我上次與關系犯了一個錯誤，它應該是一個引用employee主鍵的address中的外鍵（在這種情況下，我是用戶列ID ）

UPDATE2從Address排除ID，在調用ds.WriteXML("test.xml")之前添加此行

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

您還可以添加以下行以從員工中排除ID：

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

Answer 2

您遇到的主要問題是您正在使用1個DataTable並嘗試將其分解為2個相關數據表。 最好的方法是打破你的表，這樣你有一個員工表和一個地址表，通過EmployeeId或其他東西相關。

然后，將信息拉入兩個不同的表，關聯，並相應地嵌套它們：

DataSet empList = new DataSet("EmployeeDetails");
DataTable employee = Employees;
DataTable address = Addresses;

empList.Add(employee);
empList.Add(address);

DataRelation relEmpAdd = new DataRelation
(
    "relEmpAdd"
    ,employee.Columns["Id"]
    ,address.Columns["EmployeeId"]
);
relEmpAdd.Nested = true;

ds.Relations.Add(relEmpAdd);