Get Enum From item (string) and Type - Runtime

Question

User-450085702 posted

Hi,

I have an enum with not-so-friendly names, so wanted to use [Description("friendly name")] on few of the enum constants. For example, I have the below enum, when I show it to user they should be Created, Order Processing, Processed instead of Created, Processing, and Processed.

public enum OrderStatus {

     Created,

     [Description("Order Processing")]  Processing,

     Processed

}

I have written this extension method that can be invoked on enum constant to get the friendly name from Description attribute.

public static string GetDescription(this Enum enumValue)
{
     var type = enumValue.GetType();
     var memberInfo = type.GetMember(enumValue.ToString());
     if (memberInfo.Length > 0)
     {
          var attrs = memberInfo[0].GetCustomAttributes(typeof(DescriptionAttribute), false);
          if (attrs.Length > 0) return ((DescriptionAttribute)attrs[0]).Description;
     }
     return null;
}

This method works great if my call is made like this: OrderStatus.Processing.GetDescription(). But because I have tons of Enums that I render on form, I am using Reflection to make this call at runtime. Let's say I am rendering this as a dropdown on the form and the property looks like the following.

[Field(Type = FieldType.Select, EnumType = typeof(OrderStatus))]

public OrderStatus? OrderStatus  

To provide the options in the Order Status dropdown, I am currently using Enum.GetNames(fieldAttribute.EnumType) but this doesn't consider the Description Attribute. 

Question: How do I invoke .GetDescription extention method using EnumType and EnumName? I tried something like (fieldAttribute.EnumType)Enum.Parse(fieldAttribute.EnumType, EnumName).GetDescription() but type casting doesn't work this way.

Thank you in advance for looking into this and trying to help.

Regards,

Siva

Answer 1

User-939850651 posted

Hi, Hnqtxe1Hn@555

According to your codes, I found  the GetDescription method cannot be called directly because it has not completed the conversion.

I suggest you could try below codes and then it will work well.

Method GetDescription :

public static string GetDescription(this Enum enumValue)
        {
            var type = enumValue.GetType();
            var memberInfo = type.GetMember(enumValue.ToString());
            if (memberInfo.Length > 0)
            {
                Object[] attrs = memberInfo[0].GetCustomAttributes(typeof(DescriptionAttribute),false);
                if (attrs.Length > 0) {
                    return ((DescriptionAttribute)attrs[0]).Description;
                }
            }
            return null;
        }

OrderStatus.cs

public enum OrderStatus
    {
        Created,
        [Description("Order Processing")]
        Processing,
        Processed
    }

Test.cs :

static void Main(string[] args)
        {
            String Des = "Processing";
            String v = ((OrderStatus)Enum.Parse(typeof(OrderStatus),Des)).GetDescription();
            Console.WriteLine("Description is : "+ v);
        }

Result:

result picture

This should achieve what you want.

Hope this can help you.

Best regards,

Xudong Peng

Answer 2

User-450085702 posted

Hi Xudong,

Thank you very much for your response. 

Your code works perfectly fine, but in my case I don't know the Enum Type in compile time. So, I needed a generic way to convert the string to a type that will be decided in runtime.

Luckily I was able to find the solution. I have just converted the enum constant to generic type Enum so that the extension method can be called on it. Here is how it looks.

String v = (Enum.Parse(typeof(OrderStatus),Des) as Enum).GetDescription();

Regards,

Siva