"Delegate subtraction has unpredictable result" in ReSharper/C#?

Ok I got a different approach than others:

Here is simplified code:

public delegate void MyHandler (object sender);


MyHandler _myEvent;


public event MyHandler MyEvent
{
add
{
_myEvent += value;
DoSomethingElse();
}
remove
{
_myEvent -= value; // <-- ReSharper warning here
}
}

Firstly, I assumed few things before hand.

Person who is listing an event has smartphone(if it is a browser, I dont have to make these assumptions) with:

div.innerHTML = "You are at Latitude: " + latitude + ", Longitude: " + longitude;

1. GPS

2. HTML5 capability.

}

3. Javascript capability

How should I save the time stamps in the database?

Step 2. Give the (Long,Lat) as arguements to some of the (Lat,Long) to TimeZone api's like the Yahoo API (use Flag R to get the Latitude converted to Timezone) to get the users timezone.

Solution: Obviously UTC, I overlaid procedure below:

=> The users timezone is determined without user input ( I am using this because you cannot simply assume that user knows the timezone of place he lives in, I knew my timezone only after few months or something at the place :P, pretty dumb!)

The each Event table has Timezone, Event & so can also have CityName Then create another database table with classification based on CityNames. So here the user will have two columns

|---------------------------------------|
|_____NewYork________|______Sydney______|
|                    |                  |
|Event 1             |  Event 2         |
|____________________|__________________|

Step 1. Use the Geolocation of the user using the Geolocation API

    window.onload = getMyLocation;


function getMyLocation() {
if (navigator.geolocation) {
navigator.geolocation.getCurrentPosition(displayLocation);
} else {
alert("Oops, no geolocation support");
}
}


function displayLocation(position) {
var latitude = position.coords.latitude;
var longitude = position.coords.longitude;
var div = document.getElementById("location");
div.innerHTML = "You are at Latitude: " + latitude + ", Longitude: " + longitude;
}

For UI

Step 2. Give the (Long,Lat) as arguements to some of the (Lat,Long) to TimeZone api's like the Yahoo API (use Flag R to get the Latitude converted to Timezone) to get the users timezone.

=> use Google Calendar API or some of the Calendar API's

=> The users timezone is determined without user input ( I am using this because you cannot simply assume that user knows the timezone of place he lives in, I knew my timezone only after few months or something at the place :P, pretty dumb!)

The each Event table has Timezone, Event & so can also have CityName Then create another database table with classification based on CityNames. So here the user will have two columns

|---------------------------------------|
|_____NewYork________|______Sydney______|
|                    |                  |
|Event 1             |  Event 2         |
|____________________|__________________|

For UI

=> use Google Calendar API or some of the Calendar API's

Related Readings:

Related Readings:

1. Determine timezone from latitude/longitude without using web services like Geonames.org

2. Determine timezone from latitude/longitude without using web services like Geonames.org

3. Timezone lookup from latitude longitude

I know its just about showing some idea how to solve this problem. But see how accurate & light-weight it becomes on users when the Timezone is determined by using device APIs

Hope it helps!