嵌套数据表

Question

我想将一个 DataTable 嵌套到另一个 DataTable 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>

我的代码：

DataTable dt = new DataTable();
DataTable dtsmtp = new DataTable();
DataTable dtimap = new DataTable();
dt.TableName = "Mail";
dtsmtp.TableName = "SMTP";
dtimap.TableName = "IMAP";
DataColumn dcsmtp1 = new DataColumn("Server");
DataColumn dcsmtp2 = new DataColumn("Port");
DataColumn dcsmtp3 = new DataColumn("Security");
DataColumn dcsmtp4 = new DataColumn("Authmethod");

DataColumn dcimap1 = new DataColumn("Server");
DataColumn dcimap2 = new DataColumn("Port");
DataColumn dcimap3 = new DataColumn("Security");
DataColumn dcimap4 = new DataColumn("Authmethod");

DataColumn dc1 = new DataColumn("Username");
DataColumn dc2 = new DataColumn("Password");
DataColumn dc3 = new DataColumn("Mailaddress");

dtsmtp.Columns.Add(dcsmtp1);
dtsmtp.Columns.Add(dcsmtp2);
dtsmtp.Columns.Add(dcsmtp3);
dtsmtp.Columns.Add(dcsmtp4);

dtimap.Columns.Add(dcimap1);
dtimap.Columns.Add(dcimap2);
dtimap.Columns.Add(dcimap3);
dtimap.Columns.Add(dcimap4);

dt.Columns.Add(dc1);
dt.Columns.Add(dc2);
dt.Columns.Add(dc3);

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

dt.Rows.Add(dtsmtp);
dt.Rows.Add(dtimap);

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

ds.Tables.Add(dt);

如果我做对了，将 tables "SMTP" 和 "IMAP" 添加到我的主 table "Mail" 中就足够了。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>

有人能给我指出正确的方向吗？非常感谢！

编辑： 对不起！首先，我应该提到我使用 WriteXml() 将其转换为 XML 格式。插入关系后，我得到：

<Mail>
  <Username>myusername</Username>
  <Password>mypassword</Password>
  <Mailaddress>me@myserver.de</Mailaddress>
  <smtp_id>Mail_SMTP</smtp_id>
  <imap_id>Mail_IMAP</imap_id>
</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>

所以，我们很接近，但还不够接近...

代码：

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);

Answer 1

如果数据表首先需要而不是xml生成，那么数据表的结构不应像这样。它们应该放入数据集中并添加关系。这确保了适当的组织。

对于 xml 生成，最好使用其他工具，例如 XDocument class。

Answer 2

您似乎正在尝试将 dtsmtp 和 dtimap 作为行添加到您的 dt 数据表中。要获得结构，我认为你需要将 smtp 和 imap columns 添加到你的 dt 数据表，然后添加 dtsmtp 和 dtimap 当您添加其他数据时...

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);

我不确定您用来将其转换为 XML 的方法，但这是您想要的排序结构。

Answer 3

尝试添加数据集中的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：Complete Solution

--SJ

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