Get property from attribute value

Question

Having this simple class:

public class Book
{
    [DataMember]
    [Column("Bok_Name")]
    [Author("AuthorName")]
    public string Name{ get; set; }

    [DataMember]
    [Column("Bok_Publisher")]
    public string Publisher{ get; set; }
}

How can i can get the PropertyInfo from a property knowing that the attribute type is Column and the value is Bok_Name. I has trying to do this with a linq query.

Answer 1

Using reflection and the .NET extension CustomAttributeExtensions.GetCustomAttribute{T} method, you can find the properties with the custom attribute. In this case, the custom attribute is from System.ComponentModel.DataAnnotations.Schema.ColumnAttribute.

var book = new Book { Name = "Jitterbug Perfume" };

PropertyInfo bokName = typeof(Book)
    .GetProperties(BindingFlags.Public | BindingFlags.Instance) // add other bindings if needed
    .FirstOrDefault(x => x.GetCustomAttribute<ColumnAttribute>() != null
       && x.GetCustomAttribute<ColumnAttribute>().Name.Equals("Bok_Name", StringComparison.OrdinalIgnoreCase));

// the above query only gets the first property with Column attribute equal to "Bok_Name"
// if there are more than one, then use a .Where clause instead of FirstOrDefault.
if (bokName != null)
{
    string name = bokName.GetValue(book).ToString();
    // do other stuff
}