C＃列表，Foreach和类型

Question

I was wondering if there is a version of foreach that checks only for a specific type and returns it.

For example consider this class tree:

org.clixel.ClxBasic -> org.clixel.ClxObject -> org.clixel.ClxSprite -> WindowsGame1.test

Then consider this code

public List<ClxBasic> objects = new List<ClxBasic>();

foreach(GroupTester tester in objects)
{
    tester.GroupTesterOnlyProperty = true;
}

tester.GroupTesterOnlyProperty is a property created in GroupTester. Is there some way to make something like this work, like an overload of foreach, or another snippet that might help me? I want to make it easy for a programmer to sort through the lists grabbing only what type they need.

Answer 1

You can use the OfType<T> extension method for IEnumerable<T> objects.

Your loop could then look like this:

foreach(GroupTester tester in objects.OfType<GroupTester>())
{
    tester.GroupTesterOnlyProperty = true;
}

Note: This assumes that GroupTester inherits from ClxBasic .

Answer 2

foreach(GroupTester tester in objects.OfType<GroupTester>())
{
    tester.GroupTesterOnlyProperty = true;
}

As suggested by @ThePower (and then deleted), you could iterate over all objects and check the type explicitly:

foreach(var tester in objects)
{
    if (tester is GroupTester)
    {
       (tester as GroupTester).GroupTesterOnlyProperty = true;
    }
}