我使用ConfigurationManager.AppSettings [的myKey]读取从我的Windows应用程序在app.config文件中的值，但返回的值总是空，即使键存在，它有一个值，迪斯任何一个知道为什么呢？

I am using ConfigurationManager.AppSettings[myKey] to read a value from the app.config file in my windows application, but the value returned is always null, even though the key exists and it has a value, Deas any one know why?

感谢

推荐答案

一，也许更容易，另一种方法是使用一个设置文件。这种封装的创建和维护的App.config值的设计师GUI和产生code访问的值。

One, perhaps easier, alternative is to use a Settings file. This encapsulates the creation and maintenance of App.config values in a designer GUI and generates code for accessing the values.

要添加一个设置文件，右击VS中的项目，然后单击添加 - >新建项目，选择设置文件，并给它一个有意义的名称，例如： MainSettings.settings 。然后，您可以添加项目，例如富，指定其为应用程序或用户范围，定义它的类型和它分配一个值。在您的code，你可以通过简单的书面retreive值 MainSettings.Default.Foo 。

To add a Settings file, right click your project in VS and click 'Add -> New Item', select 'Settings file' and give it a meaningful name, e.g. MainSettings.settings. You can then add an item, e.g. Foo, specify whether it is application or user-wide, define it's type and a assign it a value. In your code you can retreive the value by simple writing MainSettings.Default.Foo.

编译后，您可以通过编辑配置文件更改该值。会出现设置如下： -

After compilation, you can change the value by editing the config file. The setting will appear as follows:-

<applicationSettings>
    <YourNamespace.MainSettings>
        <setting name="Foo" serializeAs="String">
            <value>Bar</value>
        </setting>
    </YourNamespace.MainSettings>
</applicationSettings>