将主键从一种形式传递到另一种形式 [英] passing primary key from one form to another

问题描述

我的项目有问题..



我有一个表单，我在datagridview中列出数据库中的所有客户。

Id是从数据库自动生成的。在这个带有d​​atagrid的表单中，我有一个用于更新记录的按钮，当用户按下此按钮时，第二个表单显示准备好更改记录的任何字段。到目前为止一直这么好



但是，在第二种形式我想保存更改，我需要Id，但我尝试过的任何ID都带有值0。 ..

Hi, I have a problem with a project..

I have one form where I list all the customers from database in a datagridview.
The Id is autogenerated from the database. At this form with the datagrid I have a button for updating a record,when users press this button the second form shows up ready to change any field of the record. So far so good

But, at the second form I want to save the changes and i need the Id, but anything I have tried the Id comes with value 0...

推荐答案

从本质上讲，这是关于表单协作的流行问题。最强大的解决方案是在表单类中实现适当的接口，并传递接口引用而不是引用Form的整个实例。有关更多详细信息，请参阅我以前的解决方案：如何以两种形式复制列表框之间的所有项目 [ ^ ]。



另请参阅此处的其他解决方案讨论。如果应用程序足够简单，解决方案就像在一个表单中声明一些 internal 属性并将对一个表单的实例的引用传递给另一个表单的实例一样简单形成。对于更复杂的项目，这种违反严格封装的样式和松散耦合可能会增加代码的意外复杂性并引发错误，因此封装良好的解决方案将是优惠。



另请参阅：

http://en.wikipedia.org/wiki/Accidental_complexity [ ^ ]，

http://en.wikipedia.org/wiki/Loose_coupling [ ^ ]。

-SA

In essence, this is the popular question about form collaboration. The most robust solution is implementation of an appropriate interface in form class and passing the interface reference instead of reference to a "whole instance" of a Form. Please see my past solution for more detail: How to copy all the items between listboxes in two forms[^].

Please also see other solutions in this discussion. If the application is simple enough, the solution could be as simple as declaring of some internal property in one form and passing a reference to the instance of one form to the instance of another form. For more complex projects, such violation of strictly encapsulated style and loose coupling could add up the the accidental complexity of the code and invite mistakes, so the well-encapsulated solution would be preferable.

Please see also:
http://en.wikipedia.org/wiki/Accidental_complexity[^],
http://en.wikipedia.org/wiki/Loose_coupling[^].

—SA

以第二种形式公开属性（用于自动ID）。

访问它第一个表单并将第二个表单中的值设置为true。

Expose a property (for auto id) in the second form.
Access it in the first form and set a value in the second form to true.

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