DataView.RowFilter - 具有多个父关系的问题 [英] DataView.RowFilter – problem with more than one parent relation

问题描述

嗨

在文档
http://msdn.microsoft.com/en-us/library/system.data.datacolumn.expression.aspx
我读到我们可以使用前缀父或子从RowFilter属性引用到另一个表。

In documentation http://msdn.microsoft.com/en-us/library/system.data.datacolumn.expression.aspx I read that we can use prefix parent or child to refer from RowFilter property to another table.

我创建了一个简单的例子，但我对子关系有问题。

I created simple example but I have problem with child relation.

我有三张桌子：

I have three tables:

设备（id，deviceName，deviceTypeId），接口（id，deviceId，interfaceName）和DeviceType（id，
名称）

Devices (id, deviceName, deviceTypeId), Interfaces(id, deviceId, interfaceName), and DeviceType(id, name)

Interfaces.deviceId和Devices.meviceTypeId是关系和外键约束。

我的样本：

      DataSet1 ds = new DataSet1();

      ds.DeviceType.Rows.Add("1", "type1");
      ds.DeviceType.Rows.Add("2", "type2");

      ds.Devices.Rows.Add("1", "device1", "1");
      ds.Interfaces.Rows.Add("1", "1", "device1_interface1");
      ds.Interfaces.Rows.Add("2", "1", "device1_interface2");

      ds.Devices.Rows.Add("2", "device2", "2");
      ds.Interfaces.Rows.Add("3", "2", "device2_interface1");
      ds.Interfaces.Rows.Add("4", "2", "device2_interface2");

      ds.AcceptChanges();

      Console.WriteLine("PARENT RELATION");
      DataView viewIntefaces = new DataView(ds.Interfaces);
      viewIntefaces.RowFilter = "Parent(FK_Devices_Interfaces).deviceName = 'device1'";
      foreach (DataRowView rowView in viewIntefaces)
      {
        Console.WriteLine(rowView["interfaceName"]);
      }

      Console.WriteLine("PARENT x2 RELATION");

      //Here I get exception:
      viewIntefaces.RowFilter = "Parent(FK_Devices_Interfaces).Parent(DeviceType_Devices).name = 'type2'";
      foreach (DataRowView rowView in viewIntefaces)
      {
        Console.WriteLine(rowView["interfaceName"]);
      }

推荐答案

如果您想根据祖父母标准过滤孙子项目，那么a dataviewmanager可能更有用;

If you want to filter grandchildren items based on grandparent criteria, then a dataviewmanager might be more useful;

dataviewmanager是数据集，数据视图是数据表的内容。

a dataviewmanager is to a dataset, what a dataview is to a datatable.

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