Question

I have a list of objects that I want to filter by an integer parameter

List<testObject> objectList = new List<testObject>();  // populate objectList with testObjects  objectList.FindAll(GroupLevel0);  private static bool GroupLevel0(testObject item) { return item._groupLevel == 0; }  private class testObject {      public string _FieldSQL = null;      public int _groupLevel; } 

What I’m looking to do is to make GroupLevel0 take in an integer as a parameter instead of hardcoding to 0. I’m working in .NET 2.0 so lambda expressions are a no-go. Is it even possible to pass a parameter into a predicate?

Thank you,

Answer 1

If you’re stuck with C# 2.0, use an anonymous method – just a slightly clunkier lambda expression (ignoring expression trees):

List<testObject> objectList = new List<testObject>(); int desiredGroupLevel = 10;  objectList.FindAll(delegate (testObject item) {     return item._groupLevel == desiredGroupLevel; }); 

Or you could still use a method call to start with:

List<testObject> objectList = new List<testObject>(); int desiredGroupLevel = 10;  objectList.FindAll(CheckGroupLevel(desiredGroupLevel));  ...  public Predicate<testItem> CheckGroupLevel(int level) {     return delegate (testItem item)     {         return item._groupLevel == level;     }; } 

If you’re using Visual Studio 2008 but targeting .NET 2.0, however, you can still use a lambda expression. It’s just a compiler trick which requires no framework support (again, ignoring expression trees).