将数据导出到
xml
，并从
xml
导入数据
xml
本质上是数据，是另外一种格式的数据。而
ADO.NET
就是用来处理数据的。所以经过
DataSet
能够很是方便的处理
xml
。下面这段程序对以下问题作出了解答：
？
生成的XML没有表之间的关系怎么办？
怎样把列数据做为子元素?(在利用数据集获得XML时)
怎样把列数据做为属性?(在利用数据集获得XML时)
怎样利用数据集造成XML文件?
怎样设置xml的namespace和prefix？
怎样控制控制文本的格式？
怎样把XML文件里的数据读入数据集?
怎样利用XML文件传递数据集架构?
怎样利用XML文件在不一样数据集之间传递更改？
using
System;
using
System.Data;
using
System.Data.OleDb;
using
General.ADONET;
using
General.ADONET.OLEDBClient;
using
System.IO;
using
System.Xml;
namespace
PlayXML
{
///<summary>
/// PlayXML 的摘要说明。
///</summary>
public class XMLPlayer
{
public XMLPlayer()
{
//
// TODO: 在此处添加构造函数逻辑
//
}
private Adapter adptEmp;
private Adapter adptDept;
private OleDbConnection conn;
private DataSet dsHR;
//初始化数据集
public voidInitDataSet()
{
string strConn = "Provider = Microsoft.Jet.OLEDB.4.0;";
strConn += "Data Source = E:\\everyday\\VS\\HELPREN\\hr.mdb;";
this.conn = new OleDbConnection(strConn);
dsHR = new DataSet();
this.adptEmp =
new Adapter(this.conn, dsHR, "employees");
this.adptDept =
new Adapter(this.conn, dsHR, "departments");
this.adptDept.Fill();
this.adptEmp.Fill();
DataTable dtDept = this.dsHR.Tables["departments"];
DataTable dtEmp = this.dsHR.Tables["employees"];
DataColumn colParent = dtDept.Columns["dept_id"];
DataColumn colChild = dtEmp.Columns["emp_department"];
dsHR.Relations.Add(
"departments_employees",
colParent, colChild);//关系
}
//怎样从DataSet获得xml？
public void GetXml()
{
Console.WriteLine(
this.dsHR.GetXml()//这个方法就是从DataSet获得xml
);
}
//生成的XML没有表之间的关系怎么办？
public void GetXmlWithRalation()
{
//指定DataRelation在DataSet中进行嵌套
//使xml序列化生成关系
this.dsHR.Relations["departments_employees"].Nested = true;
Console.WriteLine(
this.dsHR.GetXml()//这个方法就是从DataSet获得xml
);
}
//怎样把列数据做为子元素?(在利用数据集获得XML时)
public void GetSubElements()
{
DataTable dtEmp = this.dsHR.Tables["employees"];
foreach(DataColumn col in dtEmp.Columns)
{
//列的ColumnMapping属性设置为MappingType.Element就能够了
col.ColumnMapping = MappingType.Element;
}
DataTable dtDept = this.dsHR.Tables["departments"];
foreach(DataColumn col in dtDept.Columns)
{
//列的ColumnMapping属性设置为MappingType.Element就能够了
col.ColumnMapping = MappingType.Element;
}
this.dsHR.GetXml();
}
//怎样把列数据做为属性?(在利用数据集获得XML时)
public void GetAttributes()
{
DataTable dtEmp = this.dsHR.Tables["employees"];
foreach(DataColumn col in dtEmp.Columns)
{
//列的ColumnMapping属性设置为MappingType.Attribute就能够了
col.ColumnMapping = MappingType.Attribute;
}
DataTable dtDept = this.dsHR.Tables["departments"];
foreach(DataColumn col in dtDept.Columns)
{
//列的ColumnMapping属性设置为MappingType.Attribute就能够了
col.ColumnMapping = MappingType.Attribute;
}
this.dsHR.GetXml();
}
//怎样利用数据集造成XML文件?
public void WriteXml()
{
//怎样设置xml的namespace和prefix？
this.dsHR.Namespace = "ADONET";
this.dsHR.Prefix = "an";
this.dsHR.WriteXml("test.xml", XmlWriteMode.WriteSchema);
//怎样控制控制文本的格式？
StreamWriter sw = new StreamWriter("test2.xml");
XmlTextWriter xmlWriter = new XmlTextWriter(sw);
xmlWriter.Formatting = Formatting.Indented;
xmlWriter.Indentation = 10;
this.dsHR.WriteXml(xmlWriter);
xmlWriter.Close();
}
//怎样把XML文件里的数据读入数据集?
public void ReadXml()
{
DataSet dsNew = new DataSet();
dsNew.ReadXml("test.xml");
Console.WriteLine(dsNew.GetXml());
}
//怎样利用XML文件传递数据集架构?
public void TransmitSchema()
{
StreamWriter sw = new StreamWriter("test.xsd");
XmlTextWriter xmlWriter = new XmlTextWriter(sw);
this.dsHR.WriteXmlSchema(xmlWriter);
xmlWriter.Close();
DataSet dsNew = new DataSet();
dsNew.ReadXmlSchema("test.xsd");
foreach(DataTable dt in dsNew.Tables)
{
Console.WriteLine(dt.TableName);
foreach(DataColumn dc in dt.Columns)
{
Console.WriteLine(" " + dc.ColumnName);
}
}
}
//怎样利用XML文件在不一样数据集之间传递更改？
public void PlayDiffGram()
{
//为两个datatable设置主键
DataTable dtEmp = this.dsHR.Tables["employees"];
DataTable dtDept = this.dsHR.Tables["departments"];
dtEmp.PrimaryKey = new DataColumn[]
{dtEmp.Columns["emp_id"]};
dtDept.PrimaryKey = new DataColumn[]
{dtDept.Columns["dept_id"]};
//把数据集写到xml文件
StreamWriter sw = new StreamWriter("test.xml");
XmlTextWriter xmlWriter = new XmlTextWriter(sw);
this.dsHR.WriteXml(xmlWriter, XmlWriteMode.WriteSchema);
sw.Close();
//从xml文件读入数据到一个新的数据集里
DataSet dsNew = new DataSet();
dsNew.ReadXml("test.xml", XmlReadMode.ReadSchema);
dsNew.AcceptChanges();
//修改值
this.dsHR.Tables["employees"].Rows[0]["emp_name"] = "aaaaa";
dsNew.Tables["employees"].Rows[0]["emp_name"] = "ccccc";
//把新数据集里的数据输出到xml文件
Stream newStream = new MemoryStream() as Stream;
XmlTextWriter xmlNewWriter =
new XmlTextWriter(newStream, null);
xmlNewWriter.Formatting = Formatting.Indented;
dsNew.GetChanges().WriteXml(xmlNewWriter, XmlWriteMode.DiffGram);
//显示如今xml文件的内容
newStream.Position = 0;
StreamReader rdr = new StreamReader(newStream);
Console.WriteLine(rdr.ReadToEnd());
newStream.Position = 0;
//把如今的xml文件的内容读到原先的那个数据集
this.dsHR.ReadXml(newStream, XmlReadMode.DiffGram);
}
}
}
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