DataSet.GetXml Yöntem
Tanım
Önemli
Bazı bilgiler ürünün ön sürümüyle ilgilidir ve sürüm öncesinde önemli değişiklikler yapılmış olabilir. Burada verilen bilgilerle ilgili olarak Microsoft açık veya zımni hiçbir garanti vermez.
içinde depolanan verilerin XML gösterimini DataSetdöndürür.
public:
System::String ^ GetXml();public string GetXml ();member this.GetXml : unit -> stringPublic Function GetXml () As StringDöndürülenler
içinde DataSetdepolanan verilerin gösterimi olan bir dize.
Örnekler
Aşağıdaki örnek bir DataSet ve DataTableoluşturur, örnek verileri ekler ve ardından verileri XML biçiminde görüntüler.
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 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
Bu örnek, bir DataSet'ten XML dosyasına veri yazma ve VERILERI XML'den DataSet'e okuma adımlarını gösterir. Bu örnek, iki tablo içeren bir veri kümesi oluşturur, bir veri kümesini XML dosyalarına (WriteXml ve GetXml) aktarmak için iki yol kullanır ve xml dosyalarından veri kümesini içeri aktarmak için iki yol (ReadXml ve InferXmlSchema) kullanır.
Örneği derlemeden ve çalıştırmadan önce örnek dizinde dört XML dosyası oluşturmanız gerekir. İlk olarak ElementsWithAttributes.xml oluşturun:
<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>
Ardından, ElementsWithChildElementsxml.xml oluşturun:
<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>
Şimdi ElementsWithOnlyAttributes.xml oluşturun:
<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>
Son olarak da RepeatingElements.xml oluşturun:
<MySchool>
<Course>C1045</Course>
<Course>C1061</Course>
<Department>Engineering</Department>
<Department>Mathematics</Department>
</MySchool>
Artık aşağıdaki kaynak kodunu derleyebilir ve çalıştırabilirsiniz.
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();
}
}
}
Açıklamalar
Bu yöntemin çağrılması, olarak ayarlanmış IgnoreSchemaçağrısıyla WriteXmlXmlWriteMode aynıdır.
GetXml XML'yi dize olarak döndürür ve bu nedenle bir dosyaya XML yazmaktan daha fazla WriteXml ek yük gerektirir.
Şema çıkarımı kullanarak bir DataSet oluşturur ve XML veya Web hizmetleri kullanarak serileştirirseniz, sütun sıralama değişebilir.
Şunlara uygulanır
Ayrıca bkz.
GitHub'da bizimle işbirliği yapın
Bu içeriğin kaynağı GitHub'da bulunabilir; burada ayrıca sorunları ve çekme isteklerini oluşturup gözden geçirebilirsiniz. Daha fazla bilgi için katkıda bulunan kılavuzumuzu inceleyin.
