database - 如何在不知情的情况下使用对数据库所做的更改来更新 TClientDataSet？

Question

我有一个简单的 TClientDataSet 组件，用于填充一些数据感知组件。但是，如果我使用此数据集将数据插入我的数据库，我似乎无法找到将其同步回我的 TClientDataSet 组件的正确方法。

我如何实现这一目标？

Answer 1

TClientDataSet 组件有一个 Refresh 方法，它就是这样做的。不过，我花了一些时间在文档中找到了这一点。 :)

来自文档:

From DB.pas

procedure Refresh;

Re-fetches data from the database to update a dataset's view of data.

Call Refresh to ensure that an application has the latest data from a database. For example, when an application turns off filtering for a dataset, it should immediately call Refresh to display all records in the dataset, not just those that used to meet the filter condition.

Note: The Refresh method does not work for all TDataSet descendants. In particular, TQuery components do not support the Refresh method if the query is not "live". To refresh a static TQuery, close and reopen the dataset. TDataSet generates a BeforeRefresh event before refreshing the records and an AfterRefresh event afterwards.

Note: Most datasets try to maintain the current record position when you call refresh. However, this is not always possible. For example, the current record may have been deleted from the server by another user. Unidirectional datasets have no mechanism for locating the current record after a refresh, and always move back to the first record.

Warning: Unidirectional datasets refresh the data by closing and reopening the cursor. This can have unintended side effects if, for example, you have code in the BeforeClose, AfterClose, BeforeOpen, or AfterOpen event handlers.