Notes

To ensure that the location and date-time are unique when creating a new event, you can add validation checks before adding the event to the `Events` collection. Here's a modified version of your code:

```csharp
[HttpPost("create")]
public ActionResult CreateEvent([FromBody] Event ev)
{
if (ev == null)
{
return BadRequest("Invalid data");
}

// Check if an event with the same location and date-time already exists
if (Events.Any(e => e.Location == ev.Location && e.DateTime == ev.DateTime))
{
return BadRequest("An event with the same location and date-time already exists");
}

Events.Add(ev);
return Ok($"Event {ev.Name} created successfully!");
}
```

Certainly! If you want to use the event name instead of the event ID for edit and delete operations, you can modify the code accordingly. Here's an updated version:

```csharp
[HttpPost("create")]
public ActionResult CreateEvent([FromBody] Event ev)
{
if (ev == null)
{
return BadRequest("Invalid data");
}

// Check if an event with the same location and date-time already exists
if (Events.Any(e => e.Location == ev.Location && e.DateTime == ev.DateTime))
{
return BadRequest("An event with the same location and date-time already exists");
}

Events.Add(ev);
return Ok($"Event {ev.Name} created successfully!");
}

[HttpPut("edit/{eventName}")]
public ActionResult EditEvent(string eventName, [FromBody] Event updatedEvent)
{
var existingEvent = Events.FirstOrDefault(e => e.Name == eventName);

if (existingEvent == null)
{
return NotFound($"Event with name {eventName} not found");
}

// Check if the updated location and date-time conflict with other events
if (Events.Any(e => e.Name != eventName && e.Location == updatedEvent.Location && e.DateTime == updatedEvent.DateTime))
{
return BadRequest("Another event with the same location and date-time already exists");
}

// Update the existing event
existingEvent.Name = updatedEvent.Name;
existingEvent.Location = updatedEvent.Location;
existingEvent.DateTime = updatedEvent.DateTime;

return Ok($"Event {eventName} updated successfully!");
}

[HttpDelete("delete/{eventName}")]
public ActionResult DeleteEvent(string eventName)
{
var eventToRemove = Events.FirstOrDefault(e => e.Name == eventName);

if (eventToRemove == null)
{
return NotFound($"Event with name {eventName} not found");
}

Events.Remove(eventToRemove);
return Ok($"Event {eventName} deleted successfully!");
}
```

Now, the `EditEvent` and `DeleteEvent` methods use the event name as the identifier instead of the event ID. Adjustments have been made to the method parameters and how the events are located in the collection.

This modification uses the `Any` method to check if there's already an event in the `Events` collection with the same location and date-time as the new event. If a match is found, it returns a BadRequest response indicating that an event with the same details already exists. Otherwise, it adds the new event to the collection.