如何将层次结构数据从数据库加载到树形视图中 [英] How do I load hierarchical data from a database into a tree view

问题描述

我有一个包含数据的数据库表，需要将字段加载到TTreeView对象中.

I have a database table with data and need to load the fields into a TTreeView object.

该行:

ItemTree.Items.AddChild(nil, CurrentField_Text);

简单地在顶层添加一个节点.

simply adds a node to the top level.

如何指定要插入的点?

请注意，在遍历表中的数据时，我可以(例如)插入3个顶级项，然后第4个元素实际上是节点2的子元素.

Please note that while looping through the data from the table, I may (for example) insert 3 top level items and then the 4th element is actually the child of node 2.

我该如何指定?

推荐答案

这是直接从我的程序中提取的一些代码，该程序将查询中获取的值插入到树形视图中.

This is some code lifted directly from a program of mine which inserts values taken from a query into a treeview.

 tv.items.clear;
 with qCustTree do  // this is the query which 'feeds' the treeview
  try
   close;
   params[0].asinteger:= qCustWithCallsID.asinteger;
   open;
   tv.items.BeginUpdate;
  while not eof do
   begin
    father:= fieldbyname ('father').asinteger;
    if father = 0
     then node:= nil
     else node:= FindANode (father);
    lastnode:= tv.Items.AddChildObject (node, fieldbyname ('curdate').asstring,
                                        pointer (fieldbyname ('id').asinteger));
    next
   end;
  finally
   tv.items.endupdate;
   tv.fullexpand;
   tv.Selected:= tv.Items[0];
   tvchange (nil, tv.Selected);
  end;

如果返回的元组的父亲"字段为0，则在树上打开一个新的父节点，否则打开一个新的子节点.

If the 'father' field of the returned tuple is 0, then a new parent node is opened on the tree, otherwise a new child node is opened.

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