将多个DataTable添加到指定的DataSet中，转换DataSet为XML，将DataTable转换XML

DataTable dt1 = null;--表一
DataTable dt2 = null;--表二
<div><span style="COLOR: #000000">            --给table 取名添加  </span></div>            DataSet ds = new DataSet();
dt1.TableName = "DT1";
ds.Tables.Add(dt1);
dt2.TableName = "DT2";
ds.Tables.Add(dt2);

//将DataSet转换为xml对象字符串
public static string ConvertDataSetToXML(DataSet ds)
{
MemoryStream stream = null;
XmlTextWriter writer = null;

try
{
stream = new MemoryStream();
//从stream装载到XmlTextReader
writer = new XmlTextWriter(stream, Encoding.Unicode);

//用WriteXml方法写入文件.
ds.WriteXml(writer);
int count = (int)stream.Length;
byte[] arr = new byte[count];
stream.Seek(0, SeekOrigin.Begin);
stream.Read(arr, 0, count);

UnicodeEncoding utf = new UnicodeEncoding();
return utf.GetString(arr).Trim();
}
catch (System.Exception ex)
{
throw ex;
}
finally
{
if (writer != null) writer.Close();
}
}

/// <summary>
/// DataTable转换XML方法
/// </summary>
/// <param name="dtData">DataTable to be converted.</param>
/// <returns>XML string format of the DataTable.</returns>
public static string ConvertDataTableToXML(DataTable dtData)
{
DataSet dsData = new DataSet();
StringBuilder sbSQL;
StringWriter swSQL;
string XMLformat;
try
{
sbSQL = new StringBuilder();
swSQL = new StringWriter(sbSQL);
dsData.Merge(dtData, true, MissingSchemaAction.AddWithKey);
dsData.Tables[0].TableName = "DataTable";
foreach (DataColumn col in dsData.Tables[0].Columns)
{
col.ColumnMapping = MappingType.Attribute;
}
dsData.WriteXml(swSQL, XmlWriteMode.WriteSchema);
XMLformat = sbSQL.ToString();
return XMLformat;
}
catch (Exception sysException)
{
throw sysException;
}
}