Reflection (?) - Check for null or empty for each property/field in a class?

I have a simple class as such:

public class FilterParams
{
    public string MeetingId { get; set; }
    public int? ClientId { get; set; }
    public string CustNum { get; set; }
    public int AttendedAsFavor { get; set; }
    public int Rating { get; set; }
    public string Comments { get; set; }
    public int Delete { get; set; }
}

How d开发者_如何转开发o I check for each of the property in the class, if they are not null (int) or empty/null (for string), then I'll convert and add that property's value to a List<string>?

Thanks.

You can use LINQ to do that:

List<string> values
    = typeof(FilterParams).GetProperties()
                          .Select(prop => prop.GetValue(yourObject, null))
                          .Where(val => val != null)
                          .Select(val => val.ToString())
                          .Where(str => str.Length > 0)
                          .ToList();

Not the finest approach but roughly:

Assuming obj is the instance of your class:

Type type = typeof(FilterParams);


foreach(PropertyInfo pi in type.GetProperties())
{
  object value = pi.GetValue(obj, null);

  if(value != null && !string.IsNullOrEmpty(value.ToString()))
     // do something
}

If you don't have a lot of such classes and not too many properties, the simplest solution is probably to write an iterator block that checks and converts each property:

public class FilterParams
{
    // ...

    public IEnumerable<string> GetValues()
    {
        if (MeetingId != null) yield return MeetingId;
        if (ClientId.HasValue) yield return ClientId.Value.ToString();
        // ...
        if (Rating != 0)       yield return Rating.ToString();
        // ...
    }
}

Usage:

FilterParams filterParams = ...

List<string> values = filterParams.GetValues().ToList();

PropertyInfo[] properties = typeof(FilterParams).GetProperties();
foreach(PropertyInfo property in properties)
{
    object value = property.GetValue(SomeFilterParamsInstance, null);
    // preform checks on value and etc. here..
}

Here's an example:

foreach (PropertyInfo item in typeof(FilterParams).GetProperties()) {
    if (item != null && !String.IsNullOrEmpty(item.ToString()) {
        //add to list, etc
     } 
}

Do you really need a reflection? Implementing a property like bool IsNull is a case for you? You can encapsulate it in interface like INullableEntity and implement in each class that need such a functionality, obviously if there are a lot of classes perhaps you have to stick with reflection.