DataTable.ReadXml 方法
定義
重要
部分資訊涉及發行前產品,在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊,不做任何明確或隱含的瑕疵擔保。
將 XML 結構與資料讀取到 DataTable.
多載
| 名稱 | Description |
|---|---|
| ReadXml(Stream) | |
| ReadXml(TextReader) |
利用指定的 DataTableXML 結構與資料讀取。TextReader |
| ReadXml(String) |
從指定的檔案讀取 XML 架構和資料。DataTable |
| ReadXml(XmlReader) |
備註
此 ReadXml 方法提供一種僅讀取資料,或同時讀取資料與結構的資料 DataTable ,從 XML 文件中讀取的方法,而該 ReadXmlSchema 方法僅讀取結構。 要同時讀取資料與結構,請使用包含參數的ReadXML超載,XmlReadMode並將其值設為 ReadSchema。
請注意,與WriteXml方法分別也是WriteXmlSchema同理。 若要撰寫 XML 資料,或同時撰寫結構與資料 DataTable,請使用該 WriteXml 方法。 如果只寫結構,就用這個 WriteXmlSchema 方法。
Note
InvalidOperationException若被讀取或寫DataRow入的欄位IDynamicMetaObjectProvider類型將被拋出,且未實作 IXmlSerializable。
ReadXml(Stream)
- 來源:
- DataTable.cs
- 來源:
- DataTable.cs
- 來源:
- DataTable.cs
- 來源:
- DataTable.cs
- 來源:
- DataTable.cs
public:
System::Data::XmlReadMode ReadXml(System::IO::Stream ^ stream);
[System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Members from serialized types may use dynamic code generation.")]
[System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members from serialized types may be trimmed if not referenced directly.")]
public System.Data.XmlReadMode ReadXml(System.IO.Stream? stream);
public System.Data.XmlReadMode ReadXml(System.IO.Stream? stream);
[System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members from serialized types may be trimmed if not referenced directly.")]
public System.Data.XmlReadMode ReadXml(System.IO.Stream? stream);
public System.Data.XmlReadMode ReadXml(System.IO.Stream stream);
[<System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Members from serialized types may use dynamic code generation.")>]
[<System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members from serialized types may be trimmed if not referenced directly.")>]
member this.ReadXml : System.IO.Stream -> System.Data.XmlReadMode
member this.ReadXml : System.IO.Stream -> System.Data.XmlReadMode
[<System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members from serialized types may be trimmed if not referenced directly.")>]
member this.ReadXml : System.IO.Stream -> System.Data.XmlReadMode
Public Function ReadXml (stream As Stream) As XmlReadMode
參數
傳回
他們 XmlReadMode 會讀取資料。
- 屬性
範例
以下範例會產生包含兩欄十列的 。DataTable 範例是透過 DataTable 呼叫 WriteXml 該方法,將結構和資料寫入記憶體串流。 範例中會建立第二個 DataTable ,並呼叫該 ReadXml 方法來填充結構與資料。
private static void DemonstrateReadWriteXMLDocumentWithStream()
{
DataTable table = CreateTestTable("XmlDemo");
PrintValues(table, "Original table");
// Write the schema and data to XML in a memory stream.
System.IO.MemoryStream xmlStream = new System.IO.MemoryStream();
table.WriteXml(xmlStream, XmlWriteMode.WriteSchema);
// Rewind the memory stream.
xmlStream.Position = 0;
DataTable newTable = new DataTable();
newTable.ReadXml(xmlStream);
// Print out values in the table.
PrintValues(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 PrintValues(DataTable table, string label)
{
// Display the contents of the supplied DataTable:
Console.WriteLine(label);
foreach (DataRow row in table.Rows)
{
foreach (DataColumn column in table.Columns)
{
Console.Write("\t{0}", row[column]);
}
Console.WriteLine();
}
}
Private Sub DemonstrateReadWriteXMLDocumentWithStream()
Dim table As DataTable = CreateTestTable("XmlDemo")
PrintValues(table, "Original table")
' Write the schema and data to XML in a memory stream.
Dim xmlStream As New System.IO.MemoryStream()
table.WriteXml(xmlStream, XmlWriteMode.WriteSchema)
' Rewind the memory stream.
xmlStream.Position = 0
Dim newTable As New DataTable
newTable.ReadXml(xmlStream)
' Print out values in the table.
PrintValues(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 PrintValues(ByVal table As DataTable, ByVal label As String)
' Display the contents of the supplied DataTable:
Console.WriteLine(label)
For Each row As DataRow In table.Rows
For Each column As DataColumn In table.Columns
Console.Write("{0}{1}", ControlChars.Tab, row(column))
Next column
Console.WriteLine()
Next row
End Sub
備註
電流 DataTable 及其後代會被載入來自所提供 Stream資料的 。 此方法的行為與該 DataSet.ReadXml 方法相同,不同之處在於資料僅載入目前資料表及其後代資料。
此 ReadXml 方法提供一種僅讀取資料,或同時讀取資料與結構的資料 DataTable ,從 XML 文件中讀取的方法,而該 ReadXmlSchema 方法僅讀取結構。
請注意,與WriteXml方法分別也是WriteXmlSchema同理。 若要撰寫 XML 資料,或同時撰寫結構與資料 DataTable,請使用該 WriteXml 方法。 如果只寫結構,就用這個 WriteXmlSchema 方法。
Note
InvalidOperationException若被讀取或寫DataRow入的欄位IDynamicMetaObjectProvider類型將被拋出,且未實作 IXmlSerializable。
若指定內聯結構,則在載入資料前,內行結構用於擴充現有關聯結構。 若存在衝突(例如同一資料表中同一欄位以不同資料型態定義),會提出例外。
若未指定內列結構,則根據 XML 文件的結構,透過推理擴展關聯結構。 若無法透過推理擴展結構以暴露所有資料,則會提出例外。
Note
當DataSet序列化 XML 中合法的 XML 字元如「_」逃逸時,也不會將 XML 元素與其對應DataColumnDataTable元素關聯。 本身 DataSet 只能逃逸 XML 元素名稱中的非法 XML 字元,因此只能消耗相同的資料。 當 XML 元素名稱中的法律字元被逃逸時,該元素在處理過程中會被忽略。
另請參閱
適用於
ReadXml(TextReader)
- 來源:
- DataTable.cs
- 來源:
- DataTable.cs
- 來源:
- DataTable.cs
- 來源:
- DataTable.cs
- 來源:
- DataTable.cs
利用指定的 DataTableXML 結構與資料讀取。TextReader
public:
System::Data::XmlReadMode ReadXml(System::IO::TextReader ^ reader);
[System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Members from serialized types may use dynamic code generation.")]
[System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members from serialized types may be trimmed if not referenced directly.")]
public System.Data.XmlReadMode ReadXml(System.IO.TextReader? reader);
public System.Data.XmlReadMode ReadXml(System.IO.TextReader? reader);
[System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members from serialized types may be trimmed if not referenced directly.")]
public System.Data.XmlReadMode ReadXml(System.IO.TextReader? reader);
public System.Data.XmlReadMode ReadXml(System.IO.TextReader reader);
[<System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Members from serialized types may use dynamic code generation.")>]
[<System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members from serialized types may be trimmed if not referenced directly.")>]
member this.ReadXml : System.IO.TextReader -> System.Data.XmlReadMode
member this.ReadXml : System.IO.TextReader -> System.Data.XmlReadMode
[<System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members from serialized types may be trimmed if not referenced directly.")>]
member this.ReadXml : System.IO.TextReader -> System.Data.XmlReadMode
Public Function ReadXml (reader As TextReader) As XmlReadMode
參數
- reader
- TextReader
TextReader那個會用來讀取資料。
傳回
他們 XmlReadMode 會讀取資料。
- 屬性
範例
以下範例會產生包含兩欄十列的 。DataTable 範例是透過 DataTable 呼叫 WriteXml 該方法,將結構和資料寫入記憶體串流。 範例中會建立第二個 DataTable ,並呼叫該 ReadXml 方法來填充結構與資料。
private static void DemonstrateReadWriteXMLDocumentWithReader()
{
DataTable table = CreateTestTable("XmlDemo");
PrintValues(table, "Original table");
// Write the schema and data to XML in a memory stream.
System.IO.MemoryStream xmlStream = new System.IO.MemoryStream();
table.WriteXml(xmlStream, XmlWriteMode.WriteSchema);
// Rewind the memory stream.
xmlStream.Position = 0;
System.IO.StreamReader reader =
new System.IO.StreamReader(xmlStream);
DataTable newTable = new DataTable();
newTable.ReadXml(reader);
// Print out values in the table.
PrintValues(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 PrintValues(DataTable table, string label)
{
Console.WriteLine(label);
foreach (DataRow row in table.Rows)
{
foreach (DataColumn column in table.Columns)
{
Console.Write("\t{0}", row[column]);
}
Console.WriteLine();
}
}
Private Sub DemonstrateReadWriteXMLDocumentWithReader()
Dim table As DataTable = CreateTestTable("XmlDemo")
PrintValues(table, "Original table")
' Write the schema and data to XML in a memory stream.
Dim xmlStream As New System.IO.MemoryStream()
table.WriteXml(xmlStream, XmlWriteMode.WriteSchema)
' Rewind the memory stream.
xmlStream.Position = 0
Dim reader As New System.IO.StreamReader(xmlStream)
Dim newTable As New DataTable
newTable.ReadXml(reader)
' Print out values in the table.
PrintValues(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 PrintValues(ByVal table As DataTable, _
ByVal label As String)
Console.WriteLine(label)
For Each row As DataRow In table.Rows
For Each column As DataColumn In table.Columns
Console.Write("{0}{1}", ControlChars.Tab, row(column))
Next column
Console.WriteLine()
Next row
End Sub
備註
電流 DataTable 及其後代會被載入來自所提供 TextReader資料的 。 此方法的行為與該 DataSet.ReadXml 方法相同,不同之處在於資料僅載入目前資料表及其後代資料。
此 ReadXml 方法提供一種僅讀取資料,或同時讀取資料與結構的資料 DataTable ,從 XML 文件中讀取的方法,而該 ReadXmlSchema 方法僅讀取結構。
請注意,與WriteXml方法分別也是WriteXmlSchema同理。 若要撰寫 XML 資料,或同時撰寫結構與資料 DataTable,請使用該 WriteXml 方法。 如果只寫結構,就用這個 WriteXmlSchema 方法。
Note
InvalidOperationException若被讀取或寫DataRow入的欄位IDynamicMetaObjectProvider類型將被拋出,且未實作 IXmlSerializable。
若指定內聯結構,則在載入資料前,內行結構用於擴充現有關聯結構。 若存在衝突(例如同一資料表中同一欄位以不同資料型態定義),會提出例外。
若未指定內列結構,則根據 XML 文件的結構,透過推理擴展關聯結構。 若無法透過推理擴展結構以暴露所有資料,則會提出例外。
Note
當DataSet序列化 XML 中合法的 XML 字元如「_」逃逸時,也不會將 XML 元素與其對應DataColumnDataTable元素關聯。 本身 DataSet 只能逃逸 XML 元素名稱中的非法 XML 字元,因此只能消耗相同的資料。 當 XML 元素名稱中的法律字元被逃逸時,該元素在處理過程中會被忽略。
另請參閱
適用於
ReadXml(String)
- 來源:
- DataTable.cs
- 來源:
- DataTable.cs
- 來源:
- DataTable.cs
- 來源:
- DataTable.cs
- 來源:
- DataTable.cs
從指定的檔案讀取 XML 架構和資料。DataTable
public:
System::Data::XmlReadMode ReadXml(System::String ^ fileName);
[System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Members from serialized types may use dynamic code generation.")]
[System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members from serialized types may be trimmed if not referenced directly.")]
public System.Data.XmlReadMode ReadXml(string fileName);
public System.Data.XmlReadMode ReadXml(string fileName);
[System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members from serialized types may be trimmed if not referenced directly.")]
public System.Data.XmlReadMode ReadXml(string fileName);
[<System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Members from serialized types may use dynamic code generation.")>]
[<System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members from serialized types may be trimmed if not referenced directly.")>]
member this.ReadXml : string -> System.Data.XmlReadMode
member this.ReadXml : string -> System.Data.XmlReadMode
[<System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members from serialized types may be trimmed if not referenced directly.")>]
member this.ReadXml : string -> System.Data.XmlReadMode
Public Function ReadXml (fileName As String) As XmlReadMode
參數
- fileName
- String
讀取資料的檔案名稱。
傳回
他們 XmlReadMode 會讀取資料。
- 屬性
範例
以下範例會產生包含兩欄十列的 。DataTable 範例中將 DataTable 結構和資料寫入磁碟。 範例中會建立第二個 DataTable ,並呼叫該 ReadXml 方法來填充結構與資料。
private static void DemonstrateReadWriteXMLDocumentWithString()
{
DataTable table = CreateTestTable("XmlDemo");
PrintValues(table, "Original table");
string fileName = "C:\\TestData.xml";
table.WriteXml(fileName, XmlWriteMode.WriteSchema);
DataTable newTable = new DataTable();
newTable.ReadXml(fileName);
// Print out values in the table.
PrintValues(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 PrintValues(DataTable table, string label)
{
Console.WriteLine(label);
foreach (DataRow row in table.Rows)
{
foreach (DataColumn column in table.Columns)
{
Console.Write("\t{0}", row[column]);
}
Console.WriteLine();
}
}
Private Sub DemonstrateReadWriteXMLDocumentWithString()
Dim table As DataTable = CreateTestTable("XmlDemo")
PrintValues(table, "Original table")
' Write the schema and data to XML in a file.
Dim fileName As String = "C:\TestData.xml"
table.WriteXml(fileName, XmlWriteMode.WriteSchema)
Dim newTable As New DataTable
newTable.ReadXml(fileName)
' Print out values in the table.
PrintValues(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 PrintValues(ByVal table As DataTable, _
ByVal label As String)
Console.WriteLine(label)
For Each row As DataRow In table.Rows
For Each column As DataColumn In table.Columns
Console.Write("{0}{1}", ControlChars.Tab, row(column))
Next column
Console.WriteLine()
Next row
End Sub
備註
當前 DataTable 檔案及其後代資料會載入所提供 String檔案中命名的檔案資料。 此方法的行為與該 DataSet.ReadXml 方法相同,不同之處在於資料僅載入目前資料表及其後代資料。
此 ReadXml 方法提供一種僅讀取資料,或同時讀取資料與結構的資料 DataTable ,從 XML 文件中讀取的方法,而該 ReadXmlSchema 方法僅讀取結構。
請注意,與WriteXml方法分別也是WriteXmlSchema同理。 若要撰寫 XML 資料,或同時撰寫結構與資料 DataTable,請使用該 WriteXml 方法。 如果只寫結構,就用這個 WriteXmlSchema 方法。
Note
InvalidOperationException若被讀取或寫DataRow入的欄位IDynamicMetaObjectProvider類型將被拋出,且未實作 IXmlSerializable。
若指定內聯結構,則在載入資料前,內行結構用於擴充現有關聯結構。 若存在衝突(例如同一資料表中同一欄位以不同資料型態定義),會提出例外。
若未指定內列結構,則根據 XML 文件的結構,透過推理擴展關聯結構。 若無法透過推理擴展結構以暴露所有資料,則會提出例外。
Note
當DataSet序列化 XML 中合法的 XML 字元如「_」逃逸時,也不會將 XML 元素與其對應DataColumnDataTable元素關聯。 本身 DataSet 只能逃逸 XML 元素名稱中的非法 XML 字元,因此只能消耗相同的資料。 當 XML 元素名稱中的法律字元被逃逸時,該元素在處理過程中會被忽略。
using System.Data;
public class A {
static void Main(string[] args) {
DataTable tabl = new DataTable("mytable");
tabl.Columns.Add(new DataColumn("id", typeof(int)));
for (int i = 0; i < 10; i++) {
DataRow row = tabl.NewRow();
row["id"] = i;
tabl.Rows.Add(row);
}
tabl.WriteXml("f.xml", XmlWriteMode.WriteSchema);
DataTable newt = new DataTable();
newt.ReadXml("f.xml");
}
}
另請參閱
適用於
ReadXml(XmlReader)
- 來源:
- DataTable.cs
- 來源:
- DataTable.cs
- 來源:
- DataTable.cs
- 來源:
- DataTable.cs
- 來源:
- DataTable.cs
public:
System::Data::XmlReadMode ReadXml(System::Xml::XmlReader ^ reader);
[System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Members from serialized types may use dynamic code generation.")]
[System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members from serialized types may be trimmed if not referenced directly.")]
public System.Data.XmlReadMode ReadXml(System.Xml.XmlReader? reader);
public System.Data.XmlReadMode ReadXml(System.Xml.XmlReader? reader);
[System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members from serialized types may be trimmed if not referenced directly.")]
public System.Data.XmlReadMode ReadXml(System.Xml.XmlReader? reader);
public System.Data.XmlReadMode ReadXml(System.Xml.XmlReader reader);
[<System.Diagnostics.CodeAnalysis.RequiresDynamicCode("Members from serialized types may use dynamic code generation.")>]
[<System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members from serialized types may be trimmed if not referenced directly.")>]
member this.ReadXml : System.Xml.XmlReader -> System.Data.XmlReadMode
member this.ReadXml : System.Xml.XmlReader -> System.Data.XmlReadMode
[<System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("Members from serialized types may be trimmed if not referenced directly.")>]
member this.ReadXml : System.Xml.XmlReader -> System.Data.XmlReadMode
Public Function ReadXml (reader As XmlReader) As XmlReadMode
參數
傳回
他們 XmlReadMode 會讀取資料。
- 屬性
範例
以下範例會產生包含兩欄十列的 。DataTable 範例將 DataTable 結構與資料寫入 XmlReader。 範例會建立第二個 DataTable ,並呼叫該 ReadXml 方法,將實例中的 XmlReader 結構和資料填入該方法。
private static void DemonstrateReadWriteXMLDocumentWithReader()
{
DataTable table = CreateTestTable("XmlDemo");
PrintValues(table, "Original table");
// Write the schema and data to XML in a memory stream.
System.IO.MemoryStream xmlStream = new System.IO.MemoryStream();
table.WriteXml(xmlStream, XmlWriteMode.WriteSchema);
// Rewind the memory stream.
xmlStream.Position = 0;
System.Xml.XmlTextReader reader =
new System.Xml.XmlTextReader(xmlStream);
DataTable newTable = new DataTable();
newTable.ReadXml(reader);
// Print out values in the table.
PrintValues(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 PrintValues(DataTable table, string label)
{
Console.WriteLine(label);
foreach (DataRow row in table.Rows)
{
foreach (DataColumn column in table.Columns)
{
Console.Write("\t{0}", row[column]);
}
Console.WriteLine();
}
}
Private Sub DemonstrateReadWriteXMLDocumentWithReader()
Dim table As DataTable = CreateTestTable("XmlDemo")
PrintValues(table, "Original table")
' Write the schema and data to XML in a memory stream.
Dim xmlStream As New System.IO.MemoryStream()
table.WriteXml(xmlStream, XmlWriteMode.WriteSchema)
' Rewind the memory stream.
xmlStream.Position = 0
Dim reader As New System.Xml.XmlTextReader(xmlStream)
Dim newTable As New DataTable
newTable.ReadXml(reader)
' Print out values in the table.
PrintValues(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 PrintValues(ByVal table As DataTable, _
ByVal label As String)
Console.WriteLine(label)
For Each row As DataRow In table.Rows
For Each column As DataColumn In table.Columns
Console.Write("{0}{1}", ControlChars.Tab, row(column))
Next column
Console.WriteLine()
Next row
End Sub
備註
當前 DataTable 檔案及其後代資料會載入所提供 XmlReader檔案中命名的檔案資料。 此方法的行為與該 ReadXml 方法相同,不同之處在於資料僅載入目前資料表及其後代資料。
此 ReadXml 方法提供一種僅讀取資料,或同時讀取資料與結構的資料 DataTable ,從 XML 文件中讀取的方法,而該 ReadXmlSchema 方法僅讀取結構。
請注意,與WriteXml方法分別也是WriteXmlSchema同理。 若要撰寫 XML 資料,或同時撰寫結構與資料 DataTable,請使用該 WriteXml 方法。 如果只寫結構,就用這個 WriteXmlSchema 方法。
Note
InvalidOperationException若被讀取或寫DataRow入的欄位IDynamicMetaObjectProvider類型將被拋出,且未實作 IXmlSerializable。
若指定內聯結構,則在載入資料前,內行結構用於擴充現有關聯結構。 若存在衝突(例如同一資料表中同一欄位以不同資料型態定義),會提出例外。
若未指定內列結構,則根據 XML 文件的結構,透過推理擴展關聯結構。 若無法透過推理擴展結構以暴露所有資料,則會提出例外。
Note
當DataSet序列化 XML 中合法的 XML 字元如「_」逃逸時,也不會將 XML 元素與其對應DataColumnDataTable元素關聯。 本身 DataSet 只能逃逸 XML 元素名稱中的非法 XML 字元,因此只能消耗相同的資料。 當 XML 元素名稱中的法律字元被逃逸時,該元素在處理過程中會被忽略。