DataSet.ReadXml 方法

参考

定义

命名空间:: System.Data

程序集:: System.Data.Common.dll

程序集:: System.Data.dll

程序集:: netstandard.dll

重要

一些信息与预发行产品相关，相应产品在发行之前可能会进行重大修改。对于此处提供的信息，Microsoft 不作任何明示或暗示的担保。

将 XML 架构和数据读入 DataSet。

重载

ReadXml(XmlReader, XmlReadMode)	使用指定的 DataSet 和 XmlReader 将 XML 架构和数据读入 XmlReadMode。
ReadXml(String, XmlReadMode)	使用指定的文件和 DataSet 将 XML 架构和数据读入 XmlReadMode。
ReadXml(Stream, XmlReadMode)	使用指定的 DataSet 和 Stream 将 XML 架构和数据读入 XmlReadMode。
ReadXml(TextReader, XmlReadMode)	使用指定的 DataSet 和 TextReader 将 XML 架构和数据读入 XmlReadMode。
ReadXml(String)	使用指定的文件将 XML 架构和数据读入 DataSet。
ReadXml(TextReader)	使用指定的 TextReader 将 XML 架构和数据读入 DataSet。
ReadXml(Stream)	使用指定的 Stream 将 XML 架构和数据读入 DataSet。
ReadXml(XmlReader)	使用指定的 XmlReader 将 XML 架构和数据读入 DataSet。

ReadXml(XmlReader, XmlReadMode)

使用指定的 DataSet 和 XmlReader 将 XML 架构和数据读入 XmlReadMode。

public:
 System::Data::XmlReadMode ReadXml(System::Xml::XmlReader ^ reader, System::Data::XmlReadMode mode);

public System.Data.XmlReadMode ReadXml (System.Xml.XmlReader? reader, System.Data.XmlReadMode mode);

public System.Data.XmlReadMode ReadXml (System.Xml.XmlReader reader, System.Data.XmlReadMode mode);

member this.ReadXml : System.Xml.XmlReader * System.Data.XmlReadMode -> System.Data.XmlReadMode

Public Function ReadXml (reader As XmlReader, mode As XmlReadMode) As XmlReadMode

参数

reader: XmlReader

从中读取的 XmlReader。

mode: XmlReadMode

XmlReadMode 值之一。

XmlReadMode

用于读取数据的 XmlReadMode。

注解

该方法 ReadXml 提供了一种仅读取数据或同时将数据和架构读取到 DataSet XML 文档中的方法，而 ReadXmlSchema 该方法仅读取架构。若要读取数据和架构，请使用包含mode参数的重载之ReadXML一，并将其值设置为 ReadSchema。

请注意，WriteXml WriteXmlSchema这两种方法都相同。若要从中 DataSet写入 XML 数据，或同时写入架构和数据，请使用 WriteXml 该方法。若要只编写架构，请使用 WriteXmlSchema 该方法。

备注

如果正在读取或写入到实现IDynamicMetaObjectProvider的DataRow列类型且不实现IXmlSerializable，则会引发一InvalidOperationException个。

如果指定了内联架构，则内联架构用于在加载数据之前扩展现有关系结构。例如，如果 (存在任何冲突，则引发异常) 时，使用不同数据类型定义的同一表中的同一列。

如果未指定任何内联架构，则根据 XML 文档的结构，根据需要通过推理扩展关系结构。如果无法通过推理扩展架构以公开所有数据，则会引发异常。

备注

它DataSet不会将 XML 元素与其对应的DataColumn``DataTable或当序列化 XML 中转义 (“_”) 等合法 XML 字符时。本身 DataSet 只对 XML 元素名称中的非法 XML 字符进行转义，因此只能使用相同的字符。当对 XML 元素名称中的法定字符进行转义时，处理时将忽略该元素。

如果包含 XML DataSet targetNamespace架构，则可能无法读取数据，并且调用ReadXml DataSet包含没有限定命名空间的元素的 XML 时可能会遇到异常。若要读取非限定元素，请在 XML 架构中设置为 elementFormDefault “限定”，如以下示例所示。

<xsd:schema id="MyDataSet"   
   elementFormDefault="qualified"   
   targetNamespace="http://www.tempuri.org/MyDataSet.xsd"   
   xmlns="http://www.tempuri.org/MyDataSet.xsd"   
   xmlns:xsd="http://www.w3.org/2001/XMLSchema"   
   xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">  
</xsd:schema>

备注

如果架构DataSet包含同名元素，但类型不同，在同一命名空间中，尝试通过指定XmlReadMode.ReadSchema将架构读取到DataSet ReadXml其中时，将引发异常。如果使用 .NET Framework 版本 1.0，则不会发生此异常。

另请参阅

在 ADO.NET 中使用数据集

适用于

ReadXml(String, XmlReadMode)

使用指定的文件和 DataSet 将 XML 架构和数据读入 XmlReadMode。

public:
 System::Data::XmlReadMode ReadXml(System::String ^ fileName, System::Data::XmlReadMode mode);

public System.Data.XmlReadMode ReadXml (string fileName, System.Data.XmlReadMode mode);

member this.ReadXml : string * System.Data.XmlReadMode -> System.Data.XmlReadMode

Public Function ReadXml (fileName As String, mode As XmlReadMode) As XmlReadMode

参数

fileName: String

作为读取源的文件名（包括路径）。

mode: XmlReadMode

XmlReadMode 值之一。

XmlReadMode

用于读取数据的 XmlReadMode。

例外

SecurityException

FileIOPermission 未设置为 Read。

注解

备注

如果正在读取或写入到实现IDynamicMetaObjectProvider的DataRow列类型且不实现IXmlSerializable，则会引发一InvalidOperationException个。

如果未指定任何内联架构，则根据 XML 文档的结构，根据需要通过推理扩展关系结构。如果无法通过推理扩展架构以公开所有数据，则会引发异常。

备注

<xsd:schema id="MyDataSet"   
   elementFormDefault="qualified"   
   targetNamespace="http://www.tempuri.org/MyDataSet.xsd"   
   xmlns="http://www.tempuri.org/MyDataSet.xsd"   
   xmlns:xsd="http://www.w3.org/2001/XMLSchema"   
   xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">  
</xsd:schema>

备注

另请参阅

在 ADO.NET 中使用数据集

适用于

ReadXml(Stream, XmlReadMode)

使用指定的 DataSet 和 Stream 将 XML 架构和数据读入 XmlReadMode。

public:
 System::Data::XmlReadMode ReadXml(System::IO::Stream ^ stream, System::Data::XmlReadMode mode);

public System.Data.XmlReadMode ReadXml (System.IO.Stream? stream, System.Data.XmlReadMode mode);

public System.Data.XmlReadMode ReadXml (System.IO.Stream stream, System.Data.XmlReadMode mode);

member this.ReadXml : System.IO.Stream * System.Data.XmlReadMode -> System.Data.XmlReadMode

Public Function ReadXml (stream As Stream, mode As XmlReadMode) As XmlReadMode

参数

stream: Stream

从中读取的 Stream。

mode: XmlReadMode

XmlReadMode 值之一。

XmlReadMode

用于读取数据的 XmlReadMode。

注解

WriteXml WriteXmlSchema这两种方法都相同。若要从中 DataSet写入 XML 数据，或同时写入架构和数据，请使用 WriteXml 该方法。若要只编写架构，请使用 WriteXmlSchema 该方法。

备注

使用ReadXml并设置为XmlReadModeDiffgram时，目标DataSet内容和原始DataSet内容可能因如何生成和处理差异而有所不同。有关差异报的详细信息，请参阅 DiffGrams。

备注

如果正在读取或写入到实现IDynamicMetaObjectProvider的DataRow列类型且不实现IXmlSerializable，则会引发一InvalidOperationException个。

如果未指定任何内联架构，则根据 XML 文档的结构，根据需要通过推理扩展关系结构。如果无法通过推理扩展架构以公开所有数据，则会引发异常。

备注

如果包含targetNamespace的 XML 架构DataSet，则可能无法读取数据，并且调用ReadXml DataSet包含没有限定命名空间的元素的 XML 时可能会遇到异常。若要读取非限定元素，请在 XML 架构中设置为 elementFormDefault “限定”，如以下示例所示。

<xsd:schema id="MyDataSet"   
   elementFormDefault="qualified"   
   targetNamespace="http://www.tempuri.org/MyDataSet.xsd"   
   xmlns="http://www.tempuri.org/MyDataSet.xsd"   
   xmlns:xsd="http://www.w3.org/2001/XMLSchema"   
   xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">  
</xsd:schema>

备注

另请参阅

在 ADO.NET 中使用数据集

适用于

ReadXml(TextReader, XmlReadMode)

使用指定的 DataSet 和 TextReader 将 XML 架构和数据读入 XmlReadMode。

public:
 System::Data::XmlReadMode ReadXml(System::IO::TextReader ^ reader, System::Data::XmlReadMode mode);

public System.Data.XmlReadMode ReadXml (System.IO.TextReader? reader, System.Data.XmlReadMode mode);

public System.Data.XmlReadMode ReadXml (System.IO.TextReader reader, System.Data.XmlReadMode mode);

member this.ReadXml : System.IO.TextReader * System.Data.XmlReadMode -> System.Data.XmlReadMode

Public Function ReadXml (reader As TextReader, mode As XmlReadMode) As XmlReadMode

参数

reader: TextReader

从中读取的 TextReader。

mode: XmlReadMode

XmlReadMode 值之一。

XmlReadMode

用于读取数据的 XmlReadMode。

注解

备注

如果正在读取或写入到实现IDynamicMetaObjectProvider的DataRow列类型且不实现IXmlSerializable，则会引发一InvalidOperationException个。

如果未指定任何内联架构，则根据 XML 文档的结构，根据需要通过推理扩展关系结构。如果无法通过推理扩展架构以公开所有数据，则会引发异常。

备注

<xsd:schema id="MyDataSet"   
   elementFormDefault="qualified"   
   targetNamespace="http://www.tempuri.org/MyDataSet.xsd"   
   xmlns="http://www.tempuri.org/MyDataSet.xsd"   
   xmlns:xsd="http://www.w3.org/2001/XMLSchema"   
   xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">  
</xsd:schema>

备注

另请参阅

在 ADO.NET 中使用数据集

适用于

ReadXml(String)

使用指定的文件将 XML 架构和数据读入 DataSet。

public:
 System::Data::XmlReadMode ReadXml(System::String ^ fileName);

public System.Data.XmlReadMode ReadXml (string fileName);

member this.ReadXml : string -> System.Data.XmlReadMode

Public Function ReadXml (fileName As String) As XmlReadMode

参数

fileName: String

作为读取源的文件名（包括路径）。

XmlReadMode

用于读取数据的 XmlReadMode。

例外

SecurityException

FileIOPermission 未设置为 Read。

示例

以下示例首先创建一个简单 DataSet ，其中包含一 DataTable列、两列和十行。架构 DataSet 和数据通过调用 WriteXml 方法写入磁盘。第二个 DataSet 创建 ReadXml ，该方法用于填充架构和数据。

private void DemonstrateReadWriteXMLDocumentWithStreamReader()
{
    // Create a DataSet with one table and two columns.
    DataSet OriginalDataSet = new DataSet("dataSet");
    OriginalDataSet.Namespace= "NetFrameWork";
    DataTable table = new DataTable("table");
    DataColumn idColumn = new DataColumn("id",
        Type.GetType("System.Int32"));
    idColumn.AutoIncrement= true;

    DataColumn itemColumn = new DataColumn("item");
    table.Columns.Add(idColumn);
    table.Columns.Add(itemColumn);
    OriginalDataSet.Tables.Add(table);

    // Add ten rows.
    DataRow newRow;
    for(int i = 0; i < 10; i++)
    {
        newRow = table.NewRow();
        newRow["item"]= "item " + i;
        table.Rows.Add(newRow);
    }
    OriginalDataSet.AcceptChanges();

    // Print out values of each table in the DataSet
    // using the function defined below.
    PrintValues(OriginalDataSet, "Original DataSet");

    // Write the schema and data to an XML file.
    string xmlFilename = "XmlDocument.xml";

    // Use WriteXml to write the document.
    OriginalDataSet.WriteXml(xmlFilename);

    // Dispose of the original DataSet.
    OriginalDataSet.Dispose();

    // Create a new DataSet.
    DataSet newDataSet = new DataSet("New DataSet");

    // Read the XML document into the DataSet.
    newDataSet.ReadXml(xmlFilename);

    // Print out values of each table in the DataSet
    // using the function defined below.
    PrintValues(newDataSet,"New DataSet");
}

private void PrintValues(DataSet dataSet, string label)
{
    Console.WriteLine("\n" + label);
    foreach(DataTable table in dataSet.Tables)
    {
        Console.WriteLine("TableName: " + table.TableName);
        foreach(DataRow row in table.Rows)
        {
            foreach(DataColumn column in table.Columns)
            {
                Console.Write("\table " + row[column] );
            }
            Console.WriteLine();
        }
    }
}

Private Sub DemonstrateReadWriteXMLDocumentWithStreamReader()
    ' Create a DataSet with one table and two columns.
    Dim OriginalDataSet As New DataSet("dataSet")
    OriginalDataSet.Namespace = "NetFrameWork"
    Dim table As New DataTable("table")
    Dim idColumn As New DataColumn("id", _
        Type.GetType("System.Int32"))
    idColumn.AutoIncrement = True

    Dim itemColumn As New DataColumn("item")
    table.Columns.Add(idColumn)
    table.Columns.Add(itemColumn)
    OriginalDataSet.Tables.Add(table)

    ' Add ten rows.
    Dim newRow As DataRow
    Dim i As Integer
    For i = 0 To 9
        newRow = table.NewRow()
        newRow("item") = "item " & i.ToString()
        table.Rows.Add(newRow)
    Next i
    OriginalDataSet.AcceptChanges()

    ' Print out values of each table in the DataSet 
    ' using the function defined below.
    PrintValues(OriginalDataSet, "Original DataSet")

    ' Write the schema and data to an XML file.
    Dim xmlFilename As String = "XmlDocument.xml"

    ' Use WriteXml to write the document.
    OriginalDataSet.WriteXml(xmlFilename)

    ' Dispose of the original DataSet.
    OriginalDataSet.Dispose()

    ' Create a new DataSet.
    Dim newDataSet As New DataSet("New DataSet")

    ' Read the XML document into the DataSet.
    newDataSet.ReadXml(xmlFilename)

    ' Print out values of each table in the DataSet 
    ' using the function defined below.
    PrintValues(newDataSet, "New DataSet")
End Sub
    
Private Sub PrintValues(dataSet As DataSet, label As String)
    Console.WriteLine(ControlChars.Cr & label)
    Dim table As DataTable
    For Each table In  dataSet.Tables
        Console.WriteLine("TableName: " & table.TableName)
        Dim row As DataRow
        For Each row In  table.Rows
            Dim column As DataColumn
            For Each column In  table.Columns
                Console.Write(ControlChars.Tab & " " & _
                    row(column).ToString())
            Next column
            Console.WriteLine()
        Next row
    Next table
End Sub

注解

备注

如果正在读取或写入到实现IDynamicMetaObjectProvider的DataRow列类型且不实现IXmlSerializable，则会引发一InvalidOperationException个。

如果未指定任何内联架构，则根据 XML 文档的结构，根据需要通过推理扩展关系结构。如果无法通过推理扩展架构以公开所有数据，则会引发异常。

备注

<xsd:schema id="MyDataSet"   
   elementFormDefault="qualified"   
   targetNamespace="http://www.tempuri.org/MyDataSet.xsd"   
   xmlns="http://www.tempuri.org/MyDataSet.xsd"   
   xmlns:xsd="http://www.w3.org/2001/XMLSchema"   
   xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">  
</xsd:schema>

备注

另请参阅

在 ADO.NET 中使用数据集

适用于

ReadXml(TextReader)

使用指定的 TextReader 将 XML 架构和数据读入 DataSet。

public:
 System::Data::XmlReadMode ReadXml(System::IO::TextReader ^ reader);

public System.Data.XmlReadMode ReadXml (System.IO.TextReader? reader);

public System.Data.XmlReadMode ReadXml (System.IO.TextReader reader);

member this.ReadXml : System.IO.TextReader -> System.Data.XmlReadMode

Public Function ReadXml (reader As TextReader) As XmlReadMode

参数

reader: TextReader

从中读取架构和数据的 TextReader。

XmlReadMode

用于读取数据的 XmlReadMode。

示例

private void DemonstrateReadWriteXMLDocumentWithFileStream()
{
    // Create a DataSet with one table and two columns.
    DataSet originalDataSet = new DataSet("dataSet");
    DataTable table = new DataTable("table");
    DataColumn idColumn = new DataColumn("id",
        Type.GetType("System.Int32"));
    idColumn.AutoIncrement= true;

    DataColumn itemColumn = new DataColumn("item");
    table.Columns.Add(idColumn);
    table.Columns.Add(itemColumn);
    originalDataSet.Tables.Add(table);
    // Add ten rows.

    DataRow newRow;
    for(int i = 0; i < 10; i++)
    {
        newRow = table.NewRow();
        newRow["item"]= "item " + i;
        table.Rows.Add(newRow);
    }
    originalDataSet.AcceptChanges();

    // Print out values of each table in the DataSet
    // using the function defined below.
    PrintValues(originalDataSet, "Original DataSet");

    // Write the schema and data to XML file with FileStream.
    string xmlFilename = "XmlDocument.xml";
    System.IO.FileStream streamWrite = new System.IO.FileStream
        (xmlFilename, System.IO.FileMode.Create);

    // Use WriteXml to write the XML document.
    originalDataSet.WriteXml(streamWrite);

    // Close the FileStream.
    streamWrite.Close();

    // Dispose of the original DataSet.
    originalDataSet.Dispose();
    // Create a new DataSet.
    DataSet newDataSet = new DataSet("New DataSet");

    // Read the XML document back in.
    // Create new FileStream to read schema with.
    System.IO.FileStream streamRead = new System.IO.FileStream
        (xmlFilename,System.IO.FileMode.Open);
    newDataSet.ReadXml(streamRead);

    // Print out values of each table in the DataSet
    // using the function defined below.
    PrintValues(newDataSet,"New DataSet");
}

private void PrintValues(DataSet dataSet, string label)
{
    Console.WriteLine("\n" + label);
    foreach(DataTable table in dataSet.Tables)
    {
        Console.WriteLine("TableName: " + table.TableName);
        foreach(DataRow row in table.Rows)
        {
            foreach(DataColumn column in table.Columns)
            {
                Console.Write("\table " + row[column] );
            }
            Console.WriteLine();
        }
    }
}

Private Sub DemonstrateReadWriteXMLDocumentWithFileStream()
    ' Create a DataSet with one table and two columns.
    Dim originalDataSet As New DataSet("dataSet")
    Dim table As New DataTable("table")
    Dim idColumn As New DataColumn("id", _
       Type.GetType("System.Int32"))
    idColumn.AutoIncrement = True

    Dim itemColumn As New DataColumn("item")
    table.Columns.Add(idColumn)
    table.Columns.Add(itemColumn)
    originalDataSet.Tables.Add(table)

    ' Add ten rows.
    Dim newRow As DataRow
    Dim i As Integer
    For i = 0 To 9
        newRow = table.NewRow()
        newRow("item") = "item " & i.ToString()
        table.Rows.Add(newRow)
    Next i
    originalDataSet.AcceptChanges()

    ' Print out values of each table in the DataSet 
    ' using the function defined below.
    PrintValues(originalDataSet, "Original DataSet")

    ' Write the schema and data to XML file with FileStream.
    Dim xmlFilename As String = "XmlDocument.xml"
    Dim streamWrite As New System.IO.FileStream _
       (xmlFilename, System.IO.FileMode.Create)

    ' Use WriteXml to write the XML document.
    originalDataSet.WriteXml(streamWrite)

    ' Close the FileStream.
    streamWrite.Close()
     
    ' Dispose of the original DataSet.
    originalDataSet.Dispose()
    ' Create a new DataSet.
    Dim newDataSet As New DataSet("New DataSet")
       
    ' Read the XML document back in. 
    ' Create new FileStream to read schema with.
    Dim streamRead As New System.IO.FileStream _
       (xmlFilename, System.IO.FileMode.Open)
     
    newDataSet.ReadXml(streamRead)
    ' Print out values of each table in the DataSet  
    ' using the function defined below.
    PrintValues(newDataSet, "New DataSet")
End Sub
   
Private Sub PrintValues(dataSet As DataSet, label As String)
    Console.WriteLine(ControlChars.Cr & label)
    Dim table As DataTable
    Dim row As DataRow
    Dim column As DataColumn
    For Each table In  dataSet.Tables
        Console.WriteLine("TableName: " & table.TableName)         
        For Each row In  table.Rows             
            For Each column In  table.Columns
                Console.Write(ControlChars.Tab & " " & _
                   row(column).ToString())
            Next column
            Console.WriteLine()
        Next row
    Next table
End Sub

注解

备注

如果正在读取或写入到实现IDynamicMetaObjectProvider的DataRow列类型且不实现IXmlSerializable，则会引发一InvalidOperationException个。

如果未指定任何内联架构，则根据 XML 文档的结构，根据需要通过推理扩展关系结构。如果无法通过推理扩展架构以公开所有数据，则会引发异常。

备注

<xsd:schema id="MyDataSet"   
   elementFormDefault="qualified"   
   targetNamespace="http://www.tempuri.org/MyDataSet.xsd"   
   xmlns="http://www.tempuri.org/MyDataSet.xsd"   
   xmlns:xsd="http://www.w3.org/2001/XMLSchema"   
   xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">  
</xsd:schema>

从类继承的 TextReader 类包括 StreamReader 和 StringReader 类。

备注

另请参阅

在 ADO.NET 中使用数据集

适用于

ReadXml(Stream)

使用指定的 Stream 将 XML 架构和数据读入 DataSet。

public:
 System::Data::XmlReadMode ReadXml(System::IO::Stream ^ stream);

public System.Data.XmlReadMode ReadXml (System.IO.Stream? stream);

public System.Data.XmlReadMode ReadXml (System.IO.Stream stream);

member this.ReadXml : System.IO.Stream -> System.Data.XmlReadMode

Public Function ReadXml (stream As Stream) As XmlReadMode

参数

stream: Stream

从 Stream 派生的对象。

XmlReadMode

用于读取数据的 XmlReadMode。

示例

private void DemonstrateReadWriteXMLDocumentWithFileStream()
{
    // Create a DataSet with one table and two columns.
    DataSet originalDataSet = new DataSet("dataSet");
    DataTable table = new DataTable("table");
    DataColumn idColumn = new DataColumn("id",
        Type.GetType("System.Int32"));
    idColumn.AutoIncrement= true;

    DataColumn itemColumn = new DataColumn("item");
    table.Columns.Add(idColumn);
    table.Columns.Add(itemColumn);
    originalDataSet.Tables.Add(table);
    // Add ten rows.

    DataRow newRow;
    for(int i = 0; i < 10; i++)
    {
        newRow = table.NewRow();
        newRow["item"]= "item " + i;
        table.Rows.Add(newRow);
    }
    originalDataSet.AcceptChanges();

    // Print out values of each table in the DataSet
    // using the function defined below.
    PrintValues(originalDataSet, "Original DataSet");

    // Write the schema and data to XML file with FileStream.
    string xmlFilename = "XmlDocument.xml";
    System.IO.FileStream streamWrite = new System.IO.FileStream
        (xmlFilename, System.IO.FileMode.Create);

    // Use WriteXml to write the XML document.
    originalDataSet.WriteXml(streamWrite);

    // Close the FileStream.
    streamWrite.Close();

    // Dispose of the original DataSet.
    originalDataSet.Dispose();
    // Create a new DataSet.
    DataSet newDataSet = new DataSet("New DataSet");

    // Read the XML document back in.
    // Create new FileStream to read schema with.
    System.IO.FileStream streamRead = new System.IO.FileStream
        (xmlFilename,System.IO.FileMode.Open);
    newDataSet.ReadXml(streamRead);

    // Print out values of each table in the DataSet
    // using the function defined below.
    PrintValues(newDataSet,"New DataSet");
}

private void PrintValues(DataSet dataSet, string label)
{
    Console.WriteLine("\n" + label);
    foreach(DataTable table in dataSet.Tables)
    {
        Console.WriteLine("TableName: " + table.TableName);
        foreach(DataRow row in table.Rows)
        {
            foreach(DataColumn column in table.Columns)
            {
                Console.Write("\table " + row[column] );
            }
            Console.WriteLine();
        }
    }
}

Private Sub DemonstrateReadWriteXMLDocumentWithFileStream()
    ' Create a DataSet with one table and two columns.
    Dim originalDataSet As New DataSet("dataSet")
    Dim table As New DataTable("table")
    Dim idColumn As New DataColumn("id", _
       Type.GetType("System.Int32"))
    idColumn.AutoIncrement = True

    Dim itemColumn As New DataColumn("item")
    table.Columns.Add(idColumn)
    table.Columns.Add(itemColumn)
    originalDataSet.Tables.Add(table)

    ' Add ten rows.
    Dim newRow As DataRow
    Dim i As Integer
    For i = 0 To 9
        newRow = table.NewRow()
        newRow("item") = "item " & i.ToString()
        table.Rows.Add(newRow)
    Next i
    originalDataSet.AcceptChanges()

    ' Print out values of each table in the DataSet 
    ' using the function defined below.
    PrintValues(originalDataSet, "Original DataSet")

    ' Write the schema and data to XML file with FileStream.
    Dim xmlFilename As String = "XmlDocument.xml"
    Dim streamWrite As New System.IO.FileStream _
       (xmlFilename, System.IO.FileMode.Create)

    ' Use WriteXml to write the XML document.
    originalDataSet.WriteXml(streamWrite)

    ' Close the FileStream.
    streamWrite.Close()
     
    ' Dispose of the original DataSet.
    originalDataSet.Dispose()
    ' Create a new DataSet.
    Dim newDataSet As New DataSet("New DataSet")
       
    ' Read the XML document back in. 
    ' Create new FileStream to read schema with.
    Dim streamRead As New System.IO.FileStream _
       (xmlFilename, System.IO.FileMode.Open)
     
    newDataSet.ReadXml(streamRead)
    ' Print out values of each table in the DataSet  
    ' using the function defined below.
    PrintValues(newDataSet, "New DataSet")
End Sub
   
Private Sub PrintValues(dataSet As DataSet, label As String)
    Console.WriteLine(ControlChars.Cr & label)
    Dim table As DataTable
    Dim row As DataRow
    Dim column As DataColumn
    For Each table In  dataSet.Tables
        Console.WriteLine("TableName: " & table.TableName)         
        For Each row In  table.Rows             
            For Each column In  table.Columns
                Console.Write(ControlChars.Tab & " " & _
                   row(column).ToString())
            Next column
            Console.WriteLine()
        Next row
    Next table
End Sub

注解

备注

如果正在读取或写入到实现IDynamicMetaObjectProvider的DataRow列类型且不实现IXmlSerializable，则会引发一InvalidOperationException个。

如果未指定任何内联架构，则根据 XML 文档的结构，根据需要通过推理扩展关系结构。如果无法通过推理扩展架构以公开所有数据，则会引发异常。

备注

<xsd:schema id="MyDataSet"   
   elementFormDefault="qualified"   
   targetNamespace="http://www.tempuri.org/MyDataSet.xsd"   
   xmlns="http://www.tempuri.org/MyDataSet.xsd"   
   xmlns:xsd="http://www.w3.org/2001/XMLSchema"   
   xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">  
</xsd:schema>

备注

另请参阅

适用于

ReadXml(XmlReader)

使用指定的 XmlReader 将 XML 架构和数据读入 DataSet。

public:
 System::Data::XmlReadMode ReadXml(System::Xml::XmlReader ^ reader);

public System.Data.XmlReadMode ReadXml (System.Xml.XmlReader? reader);

public System.Data.XmlReadMode ReadXml (System.Xml.XmlReader reader);

member this.ReadXml : System.Xml.XmlReader -> System.Data.XmlReadMode

Public Function ReadXml (reader As XmlReader) As XmlReadMode

参数

reader: XmlReader

从中读取的 XmlReader。

XmlReadMode

用于读取数据的 XmlReadMode。

示例

private void DemonstrateReadWriteXMLDocumentWithXMLReader()
{
    // Create a DataSet with one table and two columns.
    DataSet OriginalDataSet = new DataSet("dataSet");
    OriginalDataSet.Namespace= "NetFrameWork";
    DataTable table = new DataTable("table");
    DataColumn idColumn = new DataColumn("id",
        Type.GetType("System.Int32"));
    idColumn.AutoIncrement= true;

    DataColumn itemColumn = new DataColumn("item");
    table.Columns.Add(idColumn);
    table.Columns.Add(itemColumn);
    OriginalDataSet.Tables.Add(table);

    // Add ten rows.
    DataRow newRow;
    for(int i = 0; i < 10; i++)
    {
        newRow = table.NewRow();
        newRow["item"]= "item " + i;
        table.Rows.Add(newRow);
    }
    OriginalDataSet.AcceptChanges();

    // Print out values of each table in the DataSet
    // using the function defined below.
    PrintValues(OriginalDataSet, "Original DataSet");

    // Write the XML schema and data to file with FileStream.
    string xmlFilename = "XmlDocument.xml";

    // Create FileStream
    System.IO.FileStream fsWriteXml =
        new System.IO.FileStream
        (xmlFilename, System.IO.FileMode.Create);

    // Create an XmlTextWriter to write the file.
    System.Xml.XmlTextWriter xmlWriter =
        new System.Xml.XmlTextWriter
        (fsWriteXml, System.Text.Encoding.Unicode);

    // Use WriteXml to write the document.
    OriginalDataSet.WriteXml(xmlWriter, XmlWriteMode.WriteSchema);

    // Close the FileStream.
    fsWriteXml.Close();

    // Dispose of the original DataSet.
    OriginalDataSet.Dispose();

    // Create a new DataSet.
    DataSet newDataSet = new DataSet("New DataSet");

    // Read the XML document back in.
    // Create new FileStream to read schema with.
    System.IO.FileStream fsReadXml =
        new System.IO.FileStream
        (xmlFilename, System.IO.FileMode.Open);

    // Create an XmlTextReader to read the file.
    System.Xml.XmlTextReader xmlReader =
        new System.Xml.XmlTextReader(fsReadXml);

    // Read the XML document into the DataSet.
    newDataSet.ReadXml(xmlReader, XmlReadMode.ReadSchema);

    // Close the XmlTextReader
    xmlReader.Close();

    // Print out values of each table in the DataSet
    // fusing the unction defined below.
    PrintValues(newDataSet,"New DataSet");
}

private void PrintValues(DataSet dataSet, string label)
{
    Console.WriteLine("\n" + label);
    foreach(DataTable table in dataSet.Tables)
    {
        Console.WriteLine("TableName: " + table.TableName);
        foreach(DataRow row in table.Rows)
        {
            foreach(DataColumn column in table.Columns)
            {
                Console.Write("\t{0}({1})='{2}'", column.ColumnName, column.DataType.Name, row[column]);
            }
            Console.WriteLine();
        }
    }
}

Private Sub DemonstrateReadWriteXMLDocumentWithXMLReader()
    ' Create a DataSet with one table and two columns.
    Dim OriginalDataSet As New DataSet("dataSet")
    OriginalDataSet.Namespace = "NetFrameWork"
    Dim table As New DataTable("table")
    Dim idColumn As New DataColumn("id", _
        Type.GetType("System.Int32"))
    idColumn.AutoIncrement = True

    Dim itemColumn As New DataColumn("item")
    table.Columns.Add(idColumn)
    table.Columns.Add(itemColumn)
    OriginalDataSet.Tables.Add(table)

    ' Add ten rows.
    Dim newRow As DataRow
    Dim i As Integer
    For i = 0 To 9
        newRow = table.NewRow()
        newRow("item") = "item " & i.ToString()
        table.Rows.Add(newRow)
    Next i
    OriginalDataSet.AcceptChanges()

    ' Print out values of each table in the DataSet 
    ' using the function defined below.
    PrintValues(OriginalDataSet, "Original DataSet")

    ' Write the XML schema and data to file with FileStream.
    Dim xmlFilename As String = "XmlDocument.xml"

    ' Create FileStream    
    Dim fsWriteXml As New System.IO.FileStream _
        (xmlFilename, System.IO.FileMode.Create)

    ' Create an XmlTextWriter to write the file.
    Dim xmlWriter As New System.Xml.XmlTextWriter _
        (fsWriteXml, System.Text.Encoding.Unicode)

    ' Use WriteXml to write the document.
    OriginalDataSet.WriteXml(xmlWriter, XmlWriteMode.WriteSchema)

    ' Close the FileStream.
    fsWriteXml.Close()
        
    ' Dispose of the original DataSet.
    OriginalDataSet.Dispose()

    ' Create a new DataSet.
    Dim newDataSet As New DataSet("New DataSet")
        
    ' Read the XML document back in. 
    ' Create new FileStream to read schema with.
    Dim fsReadXml As New System.IO.FileStream _
        (xmlFilename, System.IO.FileMode.Open)

    ' Create an XmlTextReader to read the file.
    Dim xmlReader As New System.Xml.XmlTextReader(fsReadXml)

    ' Read the XML document into the DataSet.
    newDataSet.ReadXml(xmlReader, XmlReadMode.ReadSchema)

    ' Close the XmlTextReader
    xmlReader.Close()
        
    ' Print out values of each table in the DataSet using the 
    ' function defined below.
    PrintValues(newDataSet, "New DataSet")
End Sub
    
    
 Private Sub PrintValues(dataSet As DataSet, label As String)
     Console.WriteLine(ControlChars.Cr & label)
     Dim table As DataTable
     Dim row As DataRow
     Dim column As DataColumn
     For Each table In  dataSet.Tables
         Console.WriteLine("TableName: " & table.TableName)
         For Each row In  table.Rows
             For Each column In  table.Columns
                 Console.Write(ControlChars.Tab & "{0}({1})='{2}'", column.ColumnName, column.DataType.Name, row(column).ToString())

             Next column
             Console.WriteLine()
         Next row
     Next table
  End Sub

注解

备注

如果正在读取或写入到实现IDynamicMetaObjectProvider的DataRow列类型且不实现IXmlSerializable，则会引发一InvalidOperationException个。

如果未指定任何内联架构，则根据 XML 文档的结构，根据需要通过推理扩展关系结构。如果无法通过推理扩展架构以公开所有数据，则会引发异常。

备注

<xsd:schema id="MyDataSet"   
   elementFormDefault="qualified"   
   targetNamespace="http://www.tempuri.org/MyDataSet.xsd"   
   xmlns="http://www.tempuri.org/MyDataSet.xsd"   
   xmlns:xsd="http://www.w3.org/2001/XMLSchema"   
   xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">  
</xsd:schema>

System.Xml.XmlTextReader 从 XmlReader 继承。

备注

另请参阅

在 ADO.NET 中使用数据集

适用于

DataSet.ReadXml 方法

定义

重载

ReadXml(XmlReader, XmlReadMode)

参数

返回

注解

另请参阅

适用于

ReadXml(String, XmlReadMode)

参数

返回

例外

注解

另请参阅

适用于

ReadXml(Stream, XmlReadMode)

参数

返回

注解

另请参阅

适用于

ReadXml(TextReader, XmlReadMode)

参数

返回

注解

另请参阅

适用于

ReadXml(String)

参数

返回

例外

示例

注解

另请参阅

适用于

ReadXml(TextReader)

参数

返回

示例

注解

另请参阅

适用于

ReadXml(Stream)

参数

返回

示例

注解

另请参阅

适用于

ReadXml(XmlReader)

参数

返回

示例

注解

另请参阅

适用于

其他资源