MegaMind MegaMind - 2 months ago 23
C# Question

Query a collection using PropertyInfo object in LINQ

I have a method with a signature like this

void RefreshMethod<T>(IEnumerbale<T> lst, string propertyName) where T:class
{
Type type = typeof(T);
PropertyInfo property = type.GetProperties().Single(u => u.Name == primaryKeyProperty);
//query goes here
}


Now i want to query that collection for getting all the values whose


propertyName < 0


In a simple scenario it would be as easy as this

lst.where(u=>u.ID<0)


But here i don't have that ID property but have corresponding "PropertyInfo" object.

How should i acheive this.

kindly guide

Answer

You can lookup the property-value using property.GetValue(anObjectOfTypeT, null).

So something like:

var refreshedList =  lst.Where(l => ((int)(property.GetValue(l, null)) < 0).ToList();

This assumes the property will always be of type int though.