Generic string to enum conversion

Question

Hi

Suppose enum:

public enum SysLogsAppTypes { None, MonitorService, MonitorTool };

and here is a function to convert from the ToString() representation back to enum:

private SysLogsAppTypes Str2SysLogsAppTypes(string str)  
{  
    try  
    {  
        SysLogsAppTypes res = (SysLogsAppTypes)Enum
                                       .Parse(typeof(SysLogsAppTypes), str);  
        if (!Enum.IsDefined(typeof(SysLogsAppTypes), res)) 
            return SysLogsAppTypes.None;  
        return res;  
    }  
    catch  
    {  
    return SysLogsAppTypes.None;  
    }  
}  

Is there a way to make this Generic ??

I tried:

private T Str2enum<T>(string str)   
{  
    try  
    {  
        T res = (T)Enum.Parse(typeof(T), str);  
        if (!Enum.IsDefined(typeof(T), res)) return T.None;  
        return res;  
    }  
    catch  
    {  
        return T.None;  
    }  
}  

but I get: 'T' is a 'type parameter', which is not valid in the given context
where there is T.None

Any help ? Thanks
Micha

Answer 1

I think the default keyword is what you need:

private T Str2enum<T>(string str) where T : struct
{   
    try   
    {   
        T res = (T)Enum.Parse(typeof(T), str);   
        if (!Enum.IsDefined(typeof(T), res)) return default(T);   
        return res;   
    }   
    catch   
    {   
        return default(T);   
    }   
}   

Answer 2

Not the way you are trying it, but I use the method below to do this:

 public static bool EnumTryParse<E>(string enumVal, out E resOut) 
        where E : struct
 {
      var enumValFxd = enumVal.Replace(' ', '_');
      if (Enum.IsDefined(typeof(E), enumValFxd))
      {
          resOut = (E)Enum.Parse(typeof(E), 
             enumValFxd, true);
          return true;
      }
      // ----------------------------------------
      foreach (var value in
          Enum.GetNames(typeof (E)).Where(value => 
              value.Equals(enumValFxd, 
              StringComparison.OrdinalIgnoreCase)))
      {
          resOut = (E)Enum.Parse(typeof(E), value);
          return true;
      }
      resOut = default(E);
      return false;
 }

No exceptions thrown here ...