Remove C# attribute of a property dynamically

Question

I have a class with a set of properties As given below.

class ContactInfo
{
    [ReadOnly(true)]
    [Category(\"Contact Info\")]
    public string Mobile {          


        

Answer 1

I have to agree w/ Omu; you're really talking about two classes (view models) in this case, to support your two different views. Something like

CreateContactViewModel and EditContactViewModel

Answer 2

You can not remove the attribute at runtime, but you can use reflection to change the ReadOnly attribute's ReadOnly private backing field to False. Making it the equivalent of [ReadOnly(false)]

See this article for details:

http://codinglight.blogspot.com/2008/10/changing-attribute-parameters-at.html

Edit: fixed link

Answer 3

The CodingLight.com blog moved to blogspot (the above link is broken). See http://codinglight.blogspot.com/2008/10/changing-attribute-parameters-at.html.

Moreover, SysAdmin's followup did not mention the [RefreshProperties(RefreshProperties.All)] attribute that seems to be necessary for an actually-working solution.

Finally, I believe that even David Morton (author of the quoted article) missed one very important thing: if the class (ContactInfo, in SysAdmin's followup example) does not have at least one property with the [ReadOnly] attribute defined at compile time, then when the "isReadOnly" FieldInfo is set to true at runtime the result is that the whole class turns read-only.

Answer 4

I followed up the suggestion by Legenden. Here is what I came up with

class ContactInfo
{
        [ReadOnly(true)]
        [Category("Contact Info")]
        public string Mobile { get; set; }

        [Category("Contact Info")]
        public string Name{ get; set; }

        public void SetMobileEdit(bool allowEdit)
        {
             PropertyDescriptor descriptor =  TypeDescriptor.GetProperties(this.GetType())["Mobile"];

             ReadOnlyAttribute attrib = (ReadOnlyAttribute)descriptor.Attributes[typeof(ReadOnlyAttribute)];

             FieldInfo isReadOnly = attrib.GetType().GetField("isReadOnly", BindingFlags.NonPublic | BindingFlags.Instance);

             isReadOnly.SetValue(attrib, !allowEdit);
        }
}

Answer 5

it's not possible at the moment to remove attributes dinamycally (at runtime)

as a suggestion you can do 2 classes: one with the attributes and one without