DataTable.ReadXmlSchema Method

Reference

Definition

Namespace:: System.Data

Assembly:: System.Data.Common.dll

Assembly:: System.Data.dll

Assembly:: netstandard.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Reads an XML schema into the DataTable.

Overloads

ReadXmlSchema(XmlReader)	Reads an XML schema into the DataTable using the specified XmlReader.
ReadXmlSchema(String)	Reads an XML schema into the DataTable from the specified file.
ReadXmlSchema(TextReader)	Reads an XML schema into the DataTable using the specified TextReader.
ReadXmlSchema(Stream)	Reads an XML schema into the DataTable using the specified stream.

Remarks

Use the ReadXmlSchema method to create the schema for a DataTable. The schema includes table, relation, and constraint definitions.

To write a schema to an XML document, use the WriteXmlSchema method.

The XML schema is interpreted according to the XSD standard.

The ReadXmlSchema method is generally invoked before invoking the ReadXml method which is used to fill the DataTable.

ReadXmlSchema(XmlReader)

Source:: DataTable.cs

Source:: DataTable.cs

Source:: DataTable.cs

Reads an XML schema into the DataTable using the specified XmlReader.

public:
 void ReadXmlSchema(System::Xml::XmlReader ^ reader);

public void ReadXmlSchema (System.Xml.XmlReader? reader);

public void ReadXmlSchema (System.Xml.XmlReader reader);

member this.ReadXmlSchema : System.Xml.XmlReader -> unit

Public Sub ReadXmlSchema (reader As XmlReader)

Parameters

reader: XmlReader

The XmlReader used to read the schema information.

Examples

The following console application creates a new DataTable, and writes the schema for that table to a MemoryStream. Then, the example creates a new DataTable and reads its schema from the saved XML schema, using a XmlTextReader (which inherits from XmlReader) as its source.

private static void DemonstrateReadWriteXMLSchemaWithReader()
{
    DataTable table = CreateTestTable("XmlDemo");
    PrintSchema(table, "Original table");

    // Write the schema to XML in a memory stream.
    System.IO.MemoryStream xmlStream =
        new System.IO.MemoryStream();
    table.WriteXmlSchema(xmlStream);

    // Rewind the memory stream.
    xmlStream.Position = 0;

    DataTable newTable = new DataTable();
    System.Xml.XmlTextReader reader =
        new System.Xml.XmlTextReader(xmlStream);
    newTable.ReadXmlSchema(reader);

    // Print out values in the table.
    PrintSchema(newTable, "New table");
}

private static DataTable CreateTestTable(string tableName)
{
    // Create a test DataTable with two columns and a few rows.
    DataTable table = new DataTable(tableName);
    DataColumn column = new DataColumn("id", typeof(System.Int32));
    column.AutoIncrement = true;
    table.Columns.Add(column);

    column = new DataColumn("item", typeof(System.String));
    table.Columns.Add(column);

    // Add ten rows.
    DataRow row;
    for (int i = 0; i <= 9; i++)
    {
        row = table.NewRow();
        row["item"] = "item " + i;
        table.Rows.Add(row);
    }

    table.AcceptChanges();
    return table;
}

private static void PrintSchema(DataTable table, string label)
{
    // Display the schema of the supplied DataTable:
    Console.WriteLine(label);
    foreach (DataColumn column in table.Columns)
    {
        Console.WriteLine("\t{0}: {1}", column.ColumnName,
            column.DataType.Name);
    }
    Console.WriteLine();
}

Private Sub DemonstrateReadWriteXMLSchemaWithReader()
  Dim table As DataTable = CreateTestTable("XmlDemo")
  PrintSchema(table, "Original table")

  ' Write the schema to XML in a memory stream.
  Dim xmlStream As New System.IO.MemoryStream()
  table.WriteXmlSchema(xmlStream)

  ' Rewind the memory stream.
  xmlStream.Position = 0

  Dim newTable As New DataTable
  Dim reader As New System.Xml.XmlTextReader(xmlStream)
  newTable.ReadXmlSchema(reader)

  ' Print out values in the table.
  PrintSchema(newTable, "New Table")
End Sub

Private Function CreateTestTable(ByVal tableName As String) _
      As DataTable
  ' Create a test DataTable with two columns and a few rows.
  Dim table As New DataTable(tableName)
  Dim column As New DataColumn("id", GetType(System.Int32))
  column.AutoIncrement = True
  table.Columns.Add(column)

  column = New DataColumn("item", GetType(System.String))
  table.Columns.Add(column)

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

  table.AcceptChanges()
  Return table
End Function

Private Sub PrintSchema(ByVal table As DataTable, _
      ByVal label As String)
  ' Display the schema of the supplied DataTable:
  Console.WriteLine(label)
  For Each column As DataColumn In table.Columns
    Console.WriteLine("{0}{1}: {2}", ControlChars.Tab, _
      column.ColumnName, column.DataType.Name)
  Next column
End Sub

Remarks

Use the ReadXmlSchema method to create the schema for a DataTable. The schema includes table, relation, and constraint definitions.

To write a schema to an XML document, use the WriteXmlSchema method.

The XML schema is interpreted according to the XSD standard.

Data corruption can occur if the msdata:DataType and the xs:type types do not match. No exception will be thrown.

The ReadXmlSchema method is generally invoked before invoking the ReadXml method which is used to fill the DataTable.

Note

The way to create a nested relation using XML schema is to have implicit nested elements. Additionally, the nested relation could be re-wired, to use explicit column names. It is mandatory for elements to be implicitly nested for the corresponding DataTables to participate in a nested relation.

Applies to

ReadXmlSchema(String)

Source:: DataTable.cs

Source:: DataTable.cs

Source:: DataTable.cs

Reads an XML schema into the DataTable from the specified file.

public:
 void ReadXmlSchema(System::String ^ fileName);

public void ReadXmlSchema (string fileName);

member this.ReadXmlSchema : string -> unit

Public Sub ReadXmlSchema (fileName As String)

Parameters

fileName: String

The name of the file from which to read the schema information.

Examples

The following console application creates a new DataTable, and writes the schema for that table to a file. Then, the example creates a new DataTable and reads its schema from the saved XML schema, using the file as its source.

private static void DemonstrateReadWriteXMLSchemaWithFile()
{
    DataTable table = CreateTestTable("XmlDemo");
    PrintSchema(table, "Original table");

    // Write the schema to XML in a file.
    string xmlFile = "C:\\SchemaDemo.xml";
    table.WriteXmlSchema(xmlFile);

    DataTable newTable = new DataTable();
    newTable.ReadXmlSchema(xmlFile);

    // Print out values in the table.
    PrintSchema(newTable, "New table");
}

private static DataTable CreateTestTable(string tableName)
{
    // Create a test DataTable with two columns and a few rows.
    DataTable table = new DataTable(tableName);
    DataColumn column = new DataColumn("id", typeof(System.Int32));
    column.AutoIncrement = true;
    table.Columns.Add(column);

    column = new DataColumn("item", typeof(System.String));
    table.Columns.Add(column);

    // Add ten rows.
    DataRow row;
    for (int i = 0; i <= 9; i++)
    {
        row = table.NewRow();
        row["item"] = "item " + i;
        table.Rows.Add(row);
    }

    table.AcceptChanges();
    return table;
}

private static void PrintSchema(DataTable table, string label)
{
    // Display the schema of the supplied DataTable:
    Console.WriteLine(label);
    foreach (DataColumn column in table.Columns)
    {
        Console.WriteLine("\t{0}: {1}", column.ColumnName,
            column.DataType.Name);
    }
    Console.WriteLine();
}

Private Sub DemonstrateReadWriteXMLSchemaWithFile()
  Dim table As DataTable = CreateTestTable("XmlDemo")
  PrintSchema(table, "Original table")

  Dim xmlFile As String = "SchemaDemo.xml"

  ' Write the schema to XML.
  table.WriteXmlSchema(xmlFile)

  Dim newTable As New DataTable
  newTable.ReadXmlSchema(xmlFile)

  ' Print out values in the table.
  PrintSchema(newTable, "New Table")
End Sub

Private Function CreateTestTable(ByVal tableName As String) _
      As DataTable
  ' Create a test DataTable with two columns and a few rows.
  Dim table As New DataTable(tableName)
  Dim column As New DataColumn("id", GetType(System.Int32))
  column.AutoIncrement = True
  table.Columns.Add(column)

  column = New DataColumn("item", GetType(System.String))
  table.Columns.Add(column)

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

  table.AcceptChanges()
  Return table
End Function

Private Sub PrintSchema(ByVal table As DataTable, _
      ByVal label As String)
  ' Display the schema of the supplied DataTable:
  Console.WriteLine(label)
  For Each column As DataColumn In table.Columns
    Console.WriteLine("{0}{1}: {2}", ControlChars.Tab, _
      column.ColumnName, column.DataType.Name)
  Next column
End Sub

Remarks

Use the ReadXmlSchema method to create the schema for a DataTable. The schema includes table, relation, and constraint definitions.

To write a schema to an XML document, use the WriteXmlSchema method.

The XML schema is interpreted according to the XSD standard.

Data corruption can occur if the msdata:DataType and the xs:type types do not match. No exception will be thrown.

The ReadXmlSchema method is generally invoked before invoking the ReadXml method which is used to fill the DataTable.

To create a nested relation using XML schema, use implicit nested elements. You can also reconfigure the nested relation to use explicit column names. Elements must be implicitly nested in order for the corresponding DataTables to participate in a nested relation.

Applies to

ReadXmlSchema(TextReader)

Source:: DataTable.cs

Source:: DataTable.cs

Source:: DataTable.cs

Reads an XML schema into the DataTable using the specified TextReader.

public:
 void ReadXmlSchema(System::IO::TextReader ^ reader);

public void ReadXmlSchema (System.IO.TextReader? reader);

public void ReadXmlSchema (System.IO.TextReader reader);

member this.ReadXmlSchema : System.IO.TextReader -> unit

Public Sub ReadXmlSchema (reader As TextReader)

Parameters

reader: TextReader

The TextReader used to read the schema information.

Examples

The following console application creates a new DataTable, and writes the schema for that table to a MemoryStream. Then, the example creates a new DataTable and reads its schema from the saved XML schema, using a StreamReader (which inherits from TextReader) as its source.

private static void DemonstrateReadWriteXMLSchemaWithReader()
{
    DataTable table = CreateTestTable("XmlDemo");
    PrintSchema(table, "Original table");

    // Write the schema to XML in a memory stream.
    System.IO.MemoryStream xmlStream = new System.IO.MemoryStream();
    table.WriteXmlSchema(xmlStream);

    // Rewind the memory stream.
    xmlStream.Position = 0;

    DataTable newTable = new DataTable();
    System.IO.StreamReader reader =
        new System.IO.StreamReader(xmlStream);
    newTable.ReadXmlSchema(reader);

    // Print out values in the table.
    PrintSchema(newTable, "New table");
}

private static DataTable CreateTestTable(string tableName)
{
    // Create a test DataTable with two columns and a few rows.
    DataTable table = new DataTable(tableName);
    DataColumn column = new DataColumn("id", typeof(System.Int32));
    column.AutoIncrement = true;
    table.Columns.Add(column);

    column = new DataColumn("item", typeof(System.String));
    table.Columns.Add(column);

    // Add ten rows.
    DataRow row;
    for (int i = 0; i <= 9; i++)
    {
        row = table.NewRow();
        row["item"] = "item " + i;
        table.Rows.Add(row);
    }

    table.AcceptChanges();
    return table;
}

private static void PrintSchema(DataTable table, string label)
{
    // Display the schema of the supplied DataTable:
    Console.WriteLine(label);
    foreach (DataColumn column in table.Columns)
    {
        Console.WriteLine("\t{0}: {1}",
            column.ColumnName, column.DataType.Name);
    }
    Console.WriteLine();
}

Private Sub DemonstrateReadWriteXMLSchemaWithReader()
  Dim table As DataTable = CreateTestTable("XmlDemo")
  PrintSchema(table, "Original table")

  ' Write the schema to XML in a memory stream.
  Dim xmlStream As New System.IO.MemoryStream()
  table.WriteXmlSchema(xmlStream)

  ' Rewind the memory stream.
  xmlStream.Position = 0

  Dim newTable As New DataTable
  Dim reader As New System.IO.StreamReader(xmlStream)
  newTable.ReadXmlSchema(reader)

  ' Print out values in the table.
  PrintSchema(newTable, "New Table")
End Sub

Private Function CreateTestTable(ByVal tableName As String) _
  As DataTable

  ' Create a test DataTable with two columns and a few rows.
  Dim table As New DataTable(tableName)
  Dim column As New DataColumn("id", GetType(System.Int32))
  column.AutoIncrement = True
  table.Columns.Add(column)

  column = New DataColumn("item", GetType(System.String))
  table.Columns.Add(column)

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

  table.AcceptChanges()
  Return table
End Function

Private Sub PrintSchema(ByVal table As DataTable, _
  ByVal label As String)

  ' Display the schema of the supplied DataTable:
  Console.WriteLine(label)
  For Each column As DataColumn In table.Columns
    Console.WriteLine("{0}{1}: {2}", ControlChars.Tab, _
      column.ColumnName, column.DataType.Name)
  Next column
End Sub

Remarks

Use the ReadXmlSchema method to create the schema for a DataTable. The schema includes table, relation, and constraint definitions.

To write a schema to an XML document, use the WriteXmlSchema method.

The XML schema is interpreted according to the XSD standard.

Data corruption can occur if the msdata:DataType and the xs:type types do not match. No exception will be thrown.

The ReadXmlSchema method is generally invoked before invoking the ReadXml method which is used to fill the DataTable.

Applies to

ReadXmlSchema(Stream)

Source:: DataTable.cs

Source:: DataTable.cs

Source:: DataTable.cs

Reads an XML schema into the DataTable using the specified stream.

public:
 void ReadXmlSchema(System::IO::Stream ^ stream);

public void ReadXmlSchema (System.IO.Stream? stream);

public void ReadXmlSchema (System.IO.Stream stream);

member this.ReadXmlSchema : System.IO.Stream -> unit

Public Sub ReadXmlSchema (stream As Stream)

Parameters

stream: Stream

The stream used to read the schema.

Examples

private static void DemonstrateReadWriteXMLSchemaWithStream()
{
    DataTable table = CreateTestTable("XmlDemo");
    PrintSchema(table, "Original table");

    // Write the schema to XML in a memory stream.
    System.IO.MemoryStream xmlStream = new System.IO.MemoryStream();
    table.WriteXmlSchema(xmlStream);

    // Rewind the memory stream.
    xmlStream.Position = 0;

    DataTable newTable = new DataTable();
    newTable.ReadXmlSchema(xmlStream);

    // Print out values in the table.
    PrintSchema(newTable, "New table");
}

private static DataTable CreateTestTable(string tableName)
{
    // Create a test DataTable with two columns and a few rows.
    DataTable table = new DataTable(tableName);
    DataColumn column = new DataColumn("id", typeof(System.Int32));
    column.AutoIncrement = true;
    table.Columns.Add(column);

    column = new DataColumn("item", typeof(System.String));
    table.Columns.Add(column);

    // Add ten rows.
    DataRow row;
    for (int i = 0; i <= 9; i++)
    {
        row = table.NewRow();
        row["item"] = "item " + i;
        table.Rows.Add(row);
    }

    table.AcceptChanges();
    return table;
}

private static void PrintSchema(DataTable table, string label)
{
    // Display the schema of the supplied DataTable:
    Console.WriteLine(label);
    foreach (DataColumn column in table.Columns)
    {
        Console.WriteLine("\t{0}: {1}", column.ColumnName,
            column.DataType.Name);
    }
    Console.WriteLine();
}

Private Sub DemonstrateReadWriteXMLSchemaWithStream()
  Dim table As DataTable = CreateTestTable("XmlDemo")
  PrintSchema(table, "Original table")

  ' Write the schema to XML in a memory stream.
  Dim xmlStream As New System.IO.MemoryStream()
  table.WriteXmlSchema(xmlStream)

  ' Rewind the memory stream.
  xmlStream.Position = 0

  Dim newTable As New DataTable
  newTable.ReadXmlSchema(xmlStream)

  ' Print out values in the table.
  PrintSchema(newTable, "New Table")
End Sub

Private Function CreateTestTable(ByVal tableName As String) _
  As DataTable

  ' Create a test DataTable with two columns and a few rows.
  Dim table As New DataTable(tableName)
  Dim column As New DataColumn("id", GetType(System.Int32))
  column.AutoIncrement = True
  table.Columns.Add(column)

  column = New DataColumn("item", GetType(System.String))
  table.Columns.Add(column)

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

  table.AcceptChanges()
  Return table
End Function

Private Sub PrintSchema(ByVal table As DataTable, _
  ByVal label As String)

  ' Display the schema of the supplied DataTable:
  Console.WriteLine(label)
  For Each column As DataColumn In table.Columns
    Console.WriteLine("{0}{1}: {2}", ControlChars.Tab, _
      column.ColumnName, column.DataType.Name)
  Next column
End Sub

Remarks

Use the ReadXmlSchema method to create the schema for a DataTable. The schema includes table, relation, and constraint definitions.

To write a schema to an XML document, use the WriteXmlSchema method.

The XML schema is interpreted according to the XSD standard.

Data corruption can occur if the msdata:DataType and the xs:type types do not match. No exception will be thrown.

The ReadXmlSchema method is generally invoked before invoking the ReadXml method which is used to fill the DataTable.

To create a nested relation using XML schema, use implicit nested elements. You can also configure the nested relation to use explicit column names. Elements must be implicitly nested in order for the corresponding DataTables to participate in a nested relation.

Applies to

Megosztás a következőn keresztül:

DataTable.ReadXmlSchema Method

Definition

Overloads

Remarks

ReadXmlSchema(XmlReader)

Parameters

Examples

Remarks

See also

Applies to

ReadXmlSchema(String)

Parameters

Examples

Remarks

See also

Applies to

ReadXmlSchema(TextReader)

Parameters

Examples

Remarks

See also

Applies to

ReadXmlSchema(Stream)

Parameters

Examples

Remarks

See also

Applies to

További források