Get raw value of property attribute using Reflection-CodePudding

I need to mark some properties as passwords so that they could be automatically screened. I found a standard attribute for that:

[PasswordPropertyText]
public string ThePassword { get; set; }

Following method checks if the attribute is there:

private static bool _isPassword(PropertyInfo p)
{
    PasswordPropertyTextAttribute passProp = (PasswordPropertyTextAttribute)p.GetCustomAttribute(typeof(PasswordPropertyTextAttribute));
    return (passProp != null); // Additional condition should go here
}

Now I would like to have my own logic here:

[PasswordPropertyText] should result in true.
[PasswordPropertyText(true)] should result in true.
[PasswordPropertyText(false)] should result in false.

but the default value of PasswordPropertyTextAttribute.Password is false when the argument is omitted.

Is there any way to get the raw attribute value?

CodePudding user response：

What you're describing cannot be done using reflection.

Reflection is not looking at the code as it was written: it is looking at the model that results from that code. Since the default constructor for PasswordPropertyTextAttribute passes a false value to another constructor, the model that it produces is indistinguishable from using [PasswordPropertyText(false)].

If you want different behavior from the built-in attribute, I'd recommend creating your own attribute that has the behavior you're looking for instead.

CodePudding user response：

Since attribute constructor information are stored as metadata as well you can get the required information by calling the GetCustomAttributesData method. Have a look at this simple example:

class Program
{
    [PasswordPropertyText]
    public string Password1 { get; set; }

    [PasswordPropertyText(true)]
    public string Password2 { get; set; }

    [PasswordPropertyText(false)]
    public string Password3 { get; set; }

    static void Main(string[] args)
    {
        var props = typeof(Program).GetProperties();
        foreach(var prop in props)
        {
            var attributeData = prop.GetCustomAttributesData().First(x => x.AttributeType == typeof(PasswordPropertyTextAttribute));
            Console.WriteLine($"{prop.Name}: {(attributeData.ConstructorArguments.Cast<CustomAttributeTypedArgument?>().FirstOrDefault()?.Value ?? true)}");
        }
        Console.ReadLine();
    }
}

Output:

Password1: True
Password2: True
Password3: False