問題:我正在將System.Data.DataTable導出到XML。 到目前爲止,它工作正常。 但我想擁有屬性中的所有數據,這也很好。 但現在我的問題,如果在一列中,所有行都是NULL,沒有寫入空屬性。 因此,如果我將XML讀回數據表,它缺少這一列...如何將所有列作爲屬性將DataTable導出到Xml?
如何強制寫入所有列,即使它們是空的?
(數據類型不necessarely字符串)
public void ExportTable(string strDirectory, DataTable dtt)
{
using (System.Data.DataSet ds = new System.Data.DataSet()) {
string strTable = dtt.TableName;
ds.Tables.Add(dtt);
ds.DataSetName = strTable;
// Move data to attributes
foreach (DataTable dt in ds.Tables) {
foreach (DataColumn dc in dt.Columns) {
dc.ColumnMapping = MappingType.Attribute;
}
}
System.Xml.XmlWriterSettings settings = new System.Xml.XmlWriterSettings();
settings.Indent = true;
//settings.Encoding = System.Text.Encoding.GetEncoding("ISO-8859-1")
settings.Encoding = System.Text.Encoding.UTF8;
settings.CloseOutput = true;
settings.CheckCharacters = true;
settings.NewLineChars = "\r\n";
// vbCr & vbLf
// Write as UTF-8 with indentation
using (System.Xml.XmlWriter w = System.Xml.XmlWriter.Create(System.IO.Path.Combine(strDirectory, strTable + ".xml"), settings)) {
// Strip out timezone
foreach (DataTable dt in ds.Tables) {
foreach (DataColumn dc in dt.Columns) {
if (object.ReferenceEquals(dc.DataType, typeof(DateTime))) {
dc.DateTimeMode = DataSetDateTime.Unspecified;
}
}
}
ds.Tables[0].WriteXml(w, XmlWriteMode.IgnoreSchema);
w.Flush();
w.Close();
}
// w
}
// ds
}
// ExportTable
VB.NET原:
Public Sub ExportTable(strDirectory As String, dtt As DataTable)
Using ds As New System.Data.DataSet()
Dim strTable As String = dtt.TableName
ds.Tables.Add(dtt)
ds.DataSetName = strTable
' Move data to attributes
For Each dt As DataTable In ds.Tables
For Each dc As DataColumn In dt.Columns
dc.ColumnMapping = MappingType.Attribute
Next dc
Next dt
Dim settings As New System.Xml.XmlWriterSettings()
settings.Indent = True
'settings.Encoding = System.Text.Encoding.GetEncoding("ISO-8859-1")
settings.Encoding = System.Text.Encoding.UTF8
settings.CloseOutput = True
settings.CheckCharacters = True
settings.NewLineChars = vbCrLf ' vbCr & vbLf
' Write as UTF-8 with indentation
Using w As System.Xml.XmlWriter = System.Xml.XmlWriter.Create(System.IO.Path.Combine(strDirectory, strTable & ".xml"), settings)
' Strip out timezone
For Each dt As DataTable In ds.Tables
For Each dc As DataColumn In dt.Columns
If dc.DataType Is GetType(DateTime) Then
dc.DateTimeMode = DataSetDateTime.Unspecified
End If
Next dc
Next dt
ds.Tables(0).WriteXml(w, XmlWriteMode.IgnoreSchema)
w.Flush()
w.Close()
End Using ' w
End Using ' ds
End Sub ' ExportTable
使用XmlWriteMode.WriteSchema。在包含模式的情況下,它不會爲null值添加屬性。 – JamieSee 2012-04-19 15:58:24
@JamieSee:沒有模式會更好,因爲結果應該易於在任何編程語言中讀取,而不僅僅是.NET。 – 2012-04-19 16:12:25