如何检测，如果表单字段已经改变，而无需使用隐藏域 [英] How to detect if form field has changed without using hidden field

问题描述

我使用ASP.NET MVC 3，并有必要，如果表单字段已经在服务器端更改检测。我知道使用的技巧与隐藏字段，但我不知道是否有一种方法只需使用API​​？

I am using ASP.NET MVC 3 and have a need to detect if the form field has been changed on the server side. I know about using tricks with hidden fields, but I was wondering if there is a way to do it by just using the API?

基本上，我有编辑屏幕为我的模型和领域之一是一个可选的ID可以被指定。如果指定了场，我必须确保它是唯一的（没有其他的模式有它）。因此，编辑控制器上，我要运行验证，但只有在该领域已被更改。

Basically, I have edit screen for my model and one of the fields is an optional id that can be specified. If the field is specified, I have to insure it is unique (no other model has it). So on the edit controller, I want to run the validation but only if that field has been changed.

请注意，我并​​不需要知道previous值与新的价值，只是如果字段值已经改变了。

Please note, I don't need to know previous value vs. new value, just if the field value has changed.

推荐答案

您必须保留旧值的副本某处，并做比较。你可以将其存储在您的视图模型。

You will have to keep a copy of the old value somewhere, and do the comparison. You may store it in your View Model.

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