List.Exists返回错误的值

Question

I was using a List to store all the devices retrieved using a third party library. I am using the Exist method to determine whether a device existing inside a list.

bool bDeviceFound = _devicesFound.Exists(delegate(RCDevice device)
    {
        bool retVal = false;
        if (device != null)
        {
            Regex regex = new Regex(@"Floor[\d]+\/mycamera[\d]+");
            if (regex.IsMatch(device.FullName))
                retVal = true;
        }
        return retVal;
    });

The problem is that delegate never returns true or the execution will never reaches to the code inside the delegate. Am I doing anything wrong here? I have verified the code inside the delegate and Regular expression returns true whenever a match is found.

device.FullName assumes the value "Floor1/mycamera1" to IsMatch to return true.

As suggested by LasseV.Karlsen in one of the comment below , I tried moving the delegate method into a seperate private static bool method and put a break point there. but execution never hit there. Thanks

Answer 1

My guess is the issue lies in this line:

if (regex.IsMatch(rc.FullName))

Why are you checking rc.FullName ? Shouldn't you be checking device.FullName instead since device is what's defined in the delegate?

As a side note, you ought to move the Regex definition outside of the Exists call for better performance. Currently it gets recompiled with each iteration of the loop.