C# 嵌套数据表

我想将一个数据表嵌套到另一个数据表中，如下所示：

<Mail>
  <SMTP>
    <Server>smtp.myserver.de</Server>
      <Port>25</Port>
    <Security>STARTTLS</Security>
      <Authmethod>Login</Authmethod>
  </SMTP>
  <IMAP>
    <Server>imap.myserver.de</Server>
      <Port>993</Port>
      <Security>STARTTLS</Security>
      <Authmethod>Login</Authmethod>
  </IMAP>
  <Username>myusername</Username>
  <Password>mypassword</Password>
  <Mailaddress>me@myserver.de</Mailaddress>
</Mail>

如果我做对了，将SMTP和IMAP表添加到我的主表Mail就足够了。不幸的是，它不起作用，我只得到：

<Mail>
  <Username>SMTP</Username>
</Mail-Configuration>
<Mail-Configuration>
  <Username>IMAP</Username>
</Mail>
<Mail>
  <Username>myusername</Username>
  <Password>mypassword</Password>
  <Mailaddress>me@myserver.de</Mailaddress>
</Mail>

如果datatables不需要首先生成xml，那么datatables的结构就不应该如此。应该将它们放入数据集中并添加关系。这确保了适当的组织

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对于xml生成，最好使用其他工具，如。

看起来您正在尝试将dtsmtp和dtimap作为行添加到dt数据表中。要获得结构，我认为您需要将smtp和imap列添加到dt datatable中，然后在添加其他数据时添加dtsmtp和dtimap

dt.Columns.Add(dc1);
dt.Columns.Add(dc2);
dt.Columns.Add(dc3);
dt.Columns.Add("smtp", typeof(DataTable));
dt.Columns.Add("imap", typeof(DataTable));

dtsmtp.Rows.Add("smtp.myserver.de", "25", "STARTTLS", "Password");
dtimap.Rows.Add("imap.myserver.de", "993", "STARTTLS", "Password");

dt.Rows.Add("myusername", "mypassword", "me@myserver.de", dtsmtp, dtimap);

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我不确定要使用什么方法将其转换为XML，但这是您想要的结构。

尝试在数据集中添加所有表，并使用唯一标识列在表之间创建关系

//Create new unique column to maintain relationship between tables
DataColumn dtId = new DataColumn("Id"); //it act as primary key
dtId.ColumnMapping = MappingType.Hidden; //hide mapping column while generating xml

DataColumn dcimap_dtId = new DataColumn("Mail_Id"); // foreign key
dcimap_dtId.ColumnMapping = MappingType.Hidden;

DataColumn dcsmtp_dtId = new DataColumn("Mail_Id"); // foreign key
dcsmtp_id.ColumnMapping = MappingType.Hidden;

// add newly created columns into appropriate tables and position
...
//fill data rows as per data table column arrangement
dt.Rows.Add(1, "myusername", "mypassword", "me@myserver.de"); // 1 is primary key
dtsmtp.Rows.Add("smtp.myserver.de", "25", "STARTTLS", "Password", 1); // 1 is here act as foreign key
dtimap.Rows.Add("imap.myserver.de", "993", "STARTTLS", "Password", 1);

// add all tables inside the dataset
ds.Tables.Add(dt);
ds.Tables.Add(dtsmtp);
ds.Tables.Add(dtimap);

//create relationship between tables
DataRelation relation = new DataRelation("Mail_SMTP", dtId, dcsmtp_dtId, true);
relation.Nested = true;
ds.Relations.Add(relation);

DataRelation relation1 = new DataRelation("Mail_IMAP", dtId, dcimap_dtId, true);
relation1.Nested = true;
ds.Relations.Add(relation1);

//Write to file
ds.WriteXml("file.xml");

参考：

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-SJ

顺便说一句，这一切似乎有点糟糕。几乎可以肯定的是，有一种更好的方法可以在不嵌套数据表的情况下实现您的目标。正如您在上面的编辑中所看到的：我不知道如何正确地将关系添加到我的行中。我试过：dt.Rows.Addmyusername，mypassword，me@myserver.de关系，关系1；但是writeXML产生：。。。。。。。。。因此，SMTP&IMAP并没有像预期的那样嵌套到邮件中，您不需要将关系对象添加为表列；而是将关系对象添加到数据集。请参阅更新的代码片段，它将帮助您如何向datatable添加新行。如果你还面临问题，请告诉我嘿，忍者代码，太好了。最后，我设法将SMTP和IMAP嵌套到邮件中。不幸的是，writeXML打印出关系列。我得到：1。。。1.1如何隐藏关系列？需要将ColumnMapping类型值设置为hidden。请参阅更新解决方案。

ds.Tables.Add(dt);
ds.Tables.Add(dtimap);
ds.Tables.Add(dtsmtp);

DataRelation relation = new DataRelation("Mail_SMTP", dtsmtpId, dcsmtpdtId, true);
relation.Nested = true;
ds.Relations.Add(relation);

DataRelation relation1 = new DataRelation("Mail_IMAP", dtimapid, dcimapdtId, true);
relation1.Nested = true;
ds.Relations.Add(relation1);

dt.Rows.Add("myusername", "mypassword", "me@myserver.de", relation, relation1);

dt.Columns.Add(dc1);
dt.Columns.Add(dc2);
dt.Columns.Add(dc3);
dt.Columns.Add("smtp", typeof(DataTable));
dt.Columns.Add("imap", typeof(DataTable));

dtsmtp.Rows.Add("smtp.myserver.de", "25", "STARTTLS", "Password");
dtimap.Rows.Add("imap.myserver.de", "993", "STARTTLS", "Password");

dt.Rows.Add("myusername", "mypassword", "me@myserver.de", dtsmtp, dtimap);

//Create new unique column to maintain relationship between tables
DataColumn dtId = new DataColumn("Id"); //it act as primary key
dtId.ColumnMapping = MappingType.Hidden; //hide mapping column while generating xml

DataColumn dcimap_dtId = new DataColumn("Mail_Id"); // foreign key
dcimap_dtId.ColumnMapping = MappingType.Hidden;

DataColumn dcsmtp_dtId = new DataColumn("Mail_Id"); // foreign key
dcsmtp_id.ColumnMapping = MappingType.Hidden;

// add newly created columns into appropriate tables and position
...
//fill data rows as per data table column arrangement
dt.Rows.Add(1, "myusername", "mypassword", "me@myserver.de"); // 1 is primary key
dtsmtp.Rows.Add("smtp.myserver.de", "25", "STARTTLS", "Password", 1); // 1 is here act as foreign key
dtimap.Rows.Add("imap.myserver.de", "993", "STARTTLS", "Password", 1);

// add all tables inside the dataset
ds.Tables.Add(dt);
ds.Tables.Add(dtsmtp);
ds.Tables.Add(dtimap);

//create relationship between tables
DataRelation relation = new DataRelation("Mail_SMTP", dtId, dcsmtp_dtId, true);
relation.Nested = true;
ds.Relations.Add(relation);

DataRelation relation1 = new DataRelation("Mail_IMAP", dtId, dcimap_dtId, true);
relation1.Nested = true;
ds.Relations.Add(relation1);

//Write to file
ds.WriteXml("file.xml");