DataSet.GetXml DataSet.GetXml DataSet.GetXml DataSet.GetXml Method

Définition

Retourne la représentation XML des données stockées dans le DataSet.Returns the XML representation of the data stored in the DataSet.

public:
 System::String ^ GetXml();
public string GetXml ();
member this.GetXml : unit -> string
Public Function GetXml () As String

Retours

Chaîne qui est une représentation des données stockées dans le DataSet.A string that is a representation of the data stored in the DataSet.

Exemples

L’exemple suivant crée un DataSet et DataTable, ajoute les exemples de données, puis affiche les données au format XML.The following example creates a DataSet and DataTable, adds sample data, and then displays the data in XML format.

private static void DemonstrateGetXml()
{
    // Create a DataSet with one table containing 
    // two columns and 10 rows.
    DataSet dataSet = new DataSet("dataSet");
    DataTable table = dataSet.Tables.Add("Items");
    table.Columns.Add("id", typeof(int));
    table.Columns.Add("Item", typeof(string));

    // Add ten rows.
    DataRow row;
    for(int i = 0; i <10;i++)
    {
        row = table.NewRow();
        row["id"]= i;
        row["Item"]= "Item" + i;
        table.Rows.Add(row);
    }

    // Display the DataSet contents as XML.
    Console.WriteLine( dataSet.GetXml() );
}
Private Shared Sub DemonstrateGetXml()
	' Create a DataSet with one table 
    ' containing two columns and 10 rows.
	Dim dataSet As DataSet = New DataSet("dataSet")
	Dim table As DataTable = dataSet.Tables.Add("Items")
	table.Columns.Add("id", Type.GetType("System.Int32"))
	table.Columns.Add("Item", Type.GetType("System.String"))

	' Add ten rows.
	Dim row As DataRow
	Dim i As Integer
	For i = 0 To 9
		row = table.NewRow()
		row("id") = i
		row("Item")= "Item" & i
		table.Rows.Add(row)
	Next

	' Display the DataSet contents as XML.
	Console.WriteLine( dataSet.GetXml() )
End Sub

Cet exemple montre comment écrire des données dans un fichier XML à partir d’un jeu de données et lire les données dans le jeu de données à partir de XML.This sample demonstrates how to write data into an XML file from a DataSet and read data into DataSet from XML. Cet exemple sera créer un jeu de données avec deux tables, utilisez deux façons d’exporter un jeu de données dans les fichiers XML (WriteXml et GetXml) et utiliser deux façons (ReadXml et InferXmlSchema) pour importer un jeu de données à partir des fichiers XML.This sample will create one dataset with two tables, use two ways to export a dataset into the XML files (WriteXml and GetXml), and use two ways (ReadXml and InferXmlSchema) to import a dataset from the XML files.

Avant de compiler et exécuter l’exemple, vous devez créer quatre fichiers XML dans le répertoire d’exemple.Before you compile and run the sample, you need to create four XML files in the sample directory. Tout d’abord, créez ElementsWithAttributes.xml :First, create ElementsWithAttributes.xml:

<MySchool>  
  <Course CourseID="C1045" Year="2012"  Title="Calculus" Credits="4" DepartmentID="7">New</Course>  
  <Course CourseID="C1061" Year="2012"  Title="Physics" Credits="4" DepartmentID="1" />  
  <Department DepartmentID="1" Name="Engineering" Budget="350000" StartDate="2007-09-01T00:00:00+08:00" Administrator="2" />  
  <Department DepartmentID="7" Name="Mathematics" Budget="250024" StartDate="2007-09-01T00:00:00+08:00" Administrator="3">Cancelled</Department>  
</MySchool>  

Ensuite, créez ElementsWithChildElementsxml.xml :Next, create ElementsWithChildElementsxml.xml:

<MySchool>  
  <Course>  
    <CourseID>C1045</CourseID>  
    <Year>2012</Year>  
    <Title>Calculus</Title>  
    <Credits>4</Credits>  
    <DepartmentID>7</DepartmentID>  
  </Course>  
  <Course>  
    <CourseID>C1061</CourseID>  
    <Year>2012</Year>  
    <Title>Physics</Title>  
    <Credits>4</Credits>  
    <DepartmentID>1</DepartmentID>  
  </Course>  
  <Course>  
    <CourseID>C2021</CourseID>  
    <Year>2012</Year>  
    <Title>Composition</Title>  
    <Credits>3</Credits>  
    <DepartmentID>2</DepartmentID>  
  </Course>  
  <Course>  
    <CourseID>C2042</CourseID>  
    <Year>2012</Year>  
    <Title>Literature</Title>  
    <Credits>4</Credits>  
    <DepartmentID>2</DepartmentID>  
  </Course>  
  <Department>  
    <DepartmentID>1</DepartmentID>  
    <Name>Engineering</Name>  
    <Budget>350000</Budget>  
    <StartDate>2007-09-01T00:00:00+08:00</StartDate>  
    <Administrator>2</Administrator>  
  </Department>  
  <Department>  
    <DepartmentID>2</DepartmentID>  
    <Name>English</Name>  
    <Budget>120000</Budget>  
    <StartDate>2007-09-01T00:00:00+08:00</StartDate>  
    <Administrator>6</Administrator>  
  </Department>  
  <Department>  
    <DepartmentID>4</DepartmentID>  
    <Name>Economics</Name>  
    <Budget>200000</Budget>  
    <StartDate>2007-09-01T00:00:00+08:00</StartDate>  
    <Administrator>4</Administrator>  
  </Department>  
  <Department>  
    <DepartmentID>7</DepartmentID>  
    <Name>Mathematics</Name>  
    <Budget>250024</Budget>  
    <StartDate>2007-09-01T00:00:00+08:00</StartDate>  
    <Administrator>3</Administrator>  
  </Department>  
</MySchool>  

Créez maintenant ElementsWithOnlyAttributes.xml :Now create ElementsWithOnlyAttributes.xml:

<MySchool>  
  <Course CourseID="C1045" Year="2012"  Title="Calculus" Credits="4" DepartmentID="7" />  
  <Course CourseID="C1061" Year="2012"  Title="Physics" Credits="4" DepartmentID="1" />  
  <Department DepartmentID="1" Name="Engineering" Budget="350000" StartDate="2007-09-01T00:00:00+08:00" Administrator="2" />  
  <Department DepartmentID="7" Name="Mathematics" Budget="250024" StartDate="2007-09-01T00:00:00+08:00" Administrator="3" />  
</MySchool>  

Et enfin, créez RepeatingElements.xml :And finally, create RepeatingElements.xml:

<MySchool>  
  <Course>C1045</Course>  
  <Course>C1061</Course>  
  <Department>Engineering</Department>   
  <Department>Mathematics</Department>  
</MySchool>  

Vous pouvez maintenant compiler et exécuter le code source suivant.Now you can compile and run the following source code. Comment Store données de jeu de données dans le fichier XML a des projets Visual Basic et c# de cet exemple.How to Store Data of DataSet into XML File has Visual Basic and C# projects for this sample.

using System;  
using System.Data;  
using System.IO;  
using System.Text;  
using System.Xml;  

// Use WriteXml method to export the dataset.  
static class DataTableHelper {  
   public static void WriteDataSetToXML(DataSet dataset, String xmlFileName) {  
      using (FileStream fsWriterStream = new FileStream(xmlFileName, FileMode.Create)) {  
         using (XmlTextWriter xmlWriter = new XmlTextWriter(fsWriterStream, Encoding.Unicode)) {  
            dataset.WriteXml(xmlWriter, XmlWriteMode.WriteSchema);  
            Console.WriteLine("Write {0} to the File {1}.", dataset.DataSetName, xmlFileName);  
            Console.WriteLine();  
         }  
      }  
   }  

   // Use GetXml method to get the XML data of the dataset and then export to the file.  
   public static void GetXMLFromDataSet(DataSet dataset, String xmlFileName) {  
      using (StreamWriter writer = new StreamWriter(xmlFileName)) {  
         writer.WriteLine(dataset.GetXml());  
         Console.WriteLine("Get Xml data from {0} and write to the File {1}.", dataset.DataSetName, xmlFileName);  
         Console.WriteLine();  
      }  
   }  

   // Use ReadXml method to import the dataset from the dataset.  
   public static void ReadXmlIntoDataSet(DataSet newDataSet, String xmlFileName) {  
      using (FileStream fsReaderStream = new FileStream(xmlFileName, FileMode.Open)) {  
         using (XmlTextReader xmlReader = new XmlTextReader(fsReaderStream)) {  
            newDataSet.ReadXml(xmlReader, XmlReadMode.ReadSchema);  
         }  
      }  
   }  

   // Display the columns and value of DataSet.  
   public static void ShowDataSet(DataSet dataset) {  
      foreach (DataTable table in dataset.Tables) {  
         Console.WriteLine("Table {0}:", table.TableName);  
         ShowDataTable(table);  
      }  
   }  

   // Display the columns and value of DataTable.  
   private static void ShowDataTable(DataTable table) {  
      foreach (DataColumn col in table.Columns) {  
         Console.Write("{0,-14}", col.ColumnName);  
      }  
      Console.WriteLine("{0,-14}", "");  

      foreach (DataRow row in table.Rows) {  
         if (row.RowState == DataRowState.Deleted) {  
            foreach (DataColumn col in table.Columns) {  
               if (col.DataType.Equals(typeof(DateTime))) {  
                  Console.Write("{0,-14:d}", row[col, DataRowVersion.Original]);  
               }  
               else if (col.DataType.Equals(typeof(Decimal))) {  
                  Console.Write("{0,-14:C}", row[col, DataRowVersion.Original]);  
               }  
               else {  
                  Console.Write("{0,-14}", row[col, DataRowVersion.Original]);  
               }  
            }  
         }  
         else {  
            foreach (DataColumn col in table.Columns) {  
               if (col.DataType.Equals(typeof(DateTime))) {  
                  Console.Write("{0,-14:d}", row[col]);  
               }  
               else if (col.DataType.Equals(typeof(Decimal))) {  
                  Console.Write("{0,-14:C}", row[col]);  
               }  
               else {  
                  Console.Write("{0,-14}", row[col]);  
               }  
            }  
         }  
         Console.WriteLine("{0,-14}", "");  
      }  
   }  

   // Display the columns of DataSet.  
   public static void ShowDataSetSchema(DataSet dataSet) {  
      Console.WriteLine("{0} contains the following tables:", dataSet.DataSetName);  
      foreach (DataTable table in dataSet.Tables) {  
         Console.WriteLine("   Table {0} contains the following columns:", table.TableName);  
         ShowDataTableSchema(table);  
      }  
   }  

   // Display the columns of DataTable  
   private static void ShowDataTableSchema(DataTable table) {  
      String columnString = "";  
      foreach (DataColumn col in table.Columns) {  
         columnString += col.ColumnName + "   ";  
      }  
      Console.WriteLine(columnString);  
   }  
}  

class Program {  
   static void Main(string[] args) {  
      // Create the DataSet  
      DataSet school = new DataSet("MySchool");  
      DataTable course = CreateCourse();  
      DataTable department = CreateDepartment();  
      school.Tables.Add(course);  
      school.Tables.Add(department);  

      // Define the constraint between the tables.  
      ForeignKeyConstraint courseDepartFK = new ForeignKeyConstraint("CourseDepartFK", department.Columns["DepartmentID"], course.Columns["DepartmentID"]);  
      courseDepartFK.DeleteRule = Rule.Cascade;  
      courseDepartFK.UpdateRule = Rule.Cascade;  
      courseDepartFK.AcceptRejectRule = AcceptRejectRule.None;  
      course.Constraints.Add(courseDepartFK);  

      InsertDepartments(department);  
      InsertCourses(course);  

      // Export the dataset to the XML file.  
      Console.WriteLine("Data of the whole DataSet {0}", school.DataSetName);  
      DataTableHelper.ShowDataSet(school);  

      String xmlWithSchemaFileName = "WriterXMLWithSchema.xml";  
      String xmlGetDataFileName = "GetXML.xml";  

      // Use two ways to export the dataset to the Xml file.  
      DataTableHelper.WriteDataSetToXML(school, xmlWithSchemaFileName);  
      DataTableHelper.GetXMLFromDataSet(school, xmlGetDataFileName);  

      // Import the dataset from the XML file.  
      // Use two ways to import the dataset from the Xml file.  
      Console.WriteLine("Read Xml document into a new DataSet:");  
      DataSet newSchool = new DataSet("NewSchool");  
      DataTableHelper.ReadXmlIntoDataSet(newSchool, xmlWithSchemaFileName);  
      DataTableHelper.ShowDataSetSchema(newSchool);  
      Console.WriteLine();  

      Console.WriteLine("Infer a schema for a DataSet from an XML document:");  
      InferDataSetSchemaFromXml();  

      Console.WriteLine("Press any key to exit.");  
      Console.ReadKey();  
   }  

   static DataTable CreateCourse() {  
      DataTable course = new DataTable("Course");  
      DataColumn[] cols ={  
                              new DataColumn("CourseID",typeof(String)),  
                              new DataColumn("Year",typeof(Int32)),  
                              new DataColumn("Title",typeof(String)),  
                              new DataColumn("Credits",typeof(Int32)),  
                              new DataColumn("DepartmentID",typeof(Int32))};  
      course.Columns.AddRange(cols);  

      course.PrimaryKey = new DataColumn[] { course.Columns["CourseID"], course.Columns["Year"] };  

      return course;  
   }  

   static DataTable CreateDepartment() {  
      DataTable department = new DataTable("Department");  
      DataColumn[] cols = {   
                                new DataColumn("DepartmentID", typeof(Int32)),  
                                new DataColumn("Name",typeof(String)),  
                                new DataColumn("Budget",typeof(Decimal)),  
                                new DataColumn("StartDate",typeof(DateTime)),  
                                new DataColumn("Administrator",typeof(Int32))};  
      department.Columns.AddRange(cols);  

      department.PrimaryKey = new DataColumn[] { department.Columns["DepartmentID"] };  

      return department;  
   }  

   static void InsertDepartments(DataTable department) {  
      Object[] rows = {   
                            new Object[]{1,"Engineering",350000.00,new DateTime(2007,9,1),2},  
                            new Object[]{2,"English",120000.00,new DateTime(2007,9,1),6},  
                            new Object[]{4,"Economics",200000.00,new DateTime(2007,9,1),4},  
                            new Object[]{7,"Mathematics",250024.00,new DateTime(2007,9,1),3}};  

      foreach (Object[] row in rows) {  
         department.Rows.Add(row);  
      }  
   }  

   static void InsertCourses(DataTable course) {  
      Object[] rows ={  
                               new Object[]{"C1045",2012,"Calculus",4,7},  
                               new Object[]{"C1061",2012,"Physics",4,1},  
                               new Object[]{"C2021",2012,"Composition",3,2},  
                               new Object[]{"C2042",2012,"Literature",4,2}};  

      foreach (Object[] row in rows) {  
         course.Rows.Add(row);  
      }  
   }  

   // Display the results of inferring schema from four types of XML structures  
   private static void InferDataSetSchemaFromXml() {  
      String[] xmlFileNames = {   

                                    @"ElementsWithOnlyAttributes.xml",   
                                    @"ElementsWithAttributes.xml",  
                                    @"RepeatingElements.xml",   
                                    @"ElementsWithChildElements.xml" };  

      foreach (String xmlFileName in xmlFileNames) {  
         Console.WriteLine("Result of {0}", Path.GetFileNameWithoutExtension(xmlFileName));  
         DataSet newSchool = new DataSet();  
         newSchool.InferXmlSchema(xmlFileName, null);  
         DataTableHelper.ShowDataSetSchema(newSchool);  
         Console.WriteLine();  
      }  
   }  
}  

Remarques

Appel de cette méthode est identique à l’appel WriteXml avec XmlWriteMode défini sur IgnoreSchema.Calling this method is identical to calling WriteXml with XmlWriteMode set to IgnoreSchema.

GetXml Retourne des données XML sous forme de chaîne et nécessite donc une charge plus importante que WriteXml à écrire du code XML dans un fichier.GetXml returns XML as a string, and therefore requires more overhead than WriteXml to write XML to a file.

Si vous générez un DataSet à l’aide de l’inférence de schéma et sérialiser à l’aide de XML ou des services Web, le classement de colonne peut changer.If you build a DataSet using schema inference and serialize it using XML or Web services, the column ordering may change.

S’applique à

Voir aussi