即使 IsRequired 为 true，为什么 ConfigurationValidator 也会验证 ConfigurationProperty 的默认值？

发布于 2024-09-24 08:41:26 字数 770 浏览 5 评论 0原文

假设我有一个如下所示的配置属性。请注意，没有默认值。

[ConfigurationProperty("x", IsRequired = true)]
[StringValidator(MinLength = 1)]
public string X
{
    get { return (string)this["x"]; }
    set { this["x"] = value; }
}

现在我像这样添加我的部分：

<mySection x="123" />

我会收到此错误：

属性“x”的值不是有效的。错误是：该字符串必须长度至少为 1 个字符。

如果我更改配置属性以包含如下所示的默认值，它就会起作用：

[ConfigurationProperty("x", DefaultValue="abc", IsRequired = true)]
[StringValidator(MinLength = 1)]
public string X
{
    get { return (string)this["x"]; }
    set { this["x"] = value; }
}

这意味着即使 IsRequired 为 true，验证器也会验证默认值。这还意味着我必须在所有属性上包含虚拟默认值才能通过验证，即使它们实际上不会被使用。

这只是糟糕的设计还是有这种行为的正当理由？

原文

Let's say I have a configuration property that looks like this. Note that there is no default value.

[ConfigurationProperty("x", IsRequired = true)]
[StringValidator(MinLength = 1)]
public string X
{
    get { return (string)this["x"]; }
    set { this["x"] = value; }
}

Now I add my section like this:

<mySection x="123" />

I'll get this error:

The value for the property 'x' is not
valid. The error is: The string must
be at least 1 characters long.

It works if I change the configuration property to include a default like this:

[ConfigurationProperty("x", DefaultValue="abc", IsRequired = true)]
[StringValidator(MinLength = 1)]
public string X
{
    get { return (string)this["x"]; }
    set { this["x"] = value; }
}

This implies that validator validates the default value even if IsRequired is true. It also means that I have to include a dummy default values on all my properties to pass validation even though they won't actually be used.

Is this just bad design or is there a valid reason for this behavior?

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橪书 2024-10-01 08:41:26

我以前也遇到过这个问题。这是有正当理由的，但我不记得细节了。

我不记得这是否有效，但您可以尝试在构造函数中声明属性，其中 null 是默认值。

public class CustomConfigurationSection : ConfigurationSection
{
    public CustomConfigurationSection()
    {
        Properties.Add(new ConfigurationProperty(
            "x",
            typeof(string),
            null,
            null,
            new StringValidator(1),
            ConfigurationPropertyOptions.IsRequired));
    }


    public string X
    {
        get { return (string)this["x"]; }
        set { this["x"] = value; }
    }
}

这与使用默认值和验证器有关，但正是需要默认值的地方。
http://msdn.microsoft .com/en-us/library/system.configuration.configurationproperty(VS.85).aspx#1

编辑

我刚刚尝试了前面的代码，它的效果符合我的预期。我之前的代码没有编译，因为我错过了构造函数属性，所以我已经修复了这个问题。

I have had this problem before. There was a valid reason for this but I cannot remember the details.

I cannot remember if this works but you can try declaring the property in the constructor where null is the default value.

public class CustomConfigurationSection : ConfigurationSection
{
    public CustomConfigurationSection()
    {
        Properties.Add(new ConfigurationProperty(
            "x",
            typeof(string),
            null,
            null,
            new StringValidator(1),
            ConfigurationPropertyOptions.IsRequired));
    }


    public string X
    {
        get { return (string)this["x"]; }
        set { this["x"] = value; }
    }
}

This is related to using default values and validators but is where a default value is wanted.
http://msdn.microsoft.com/en-us/library/system.configuration.configurationproperty(VS.85).aspx#1

EDIT

I have just tried out the previous code and it does as I expected. My previous code did not compile as I missed out a constructor property so I have fixed that.

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