Boolean change when clicking the left mouse button (not working)

Question

I want to change a boolean when I click the left mouse button, but it doesn't work as expected. I use this method:

if (m.LeftButton == ButtonState.Released && m_Old.LeftButton == ButtonState.Pressed)
{
   if (second)
   {
      second = false; // Boolean changes
   } else
   {
      second = true; // Boolean changes
   }
}

I need a way to tell the code that I only want one change. When I click the left mousebutton, the second boolean changes constantly. The reason for this is that the code keeps executing until m_Old (the old mousestate) is updated. (m & m_Old must be different for this code to run)

An example (when I click the left mouse button once| these are the results for the second boolean):

My mouse update code:

// Mouse stuff
oldMouse = mouse;
mouse = Mouse.GetState();

Answer 1

Ah I think I understand the problem now. It's not really clear from the code you've posted what the problem is but I think it might have something to do with second being declared in the local scope.

I tested the code below and I believe it's working as you'd expect. I've renamed some of the variables to hopefully make it a little more understandable. It wasn't really clear from the question if second is a member variable but I believe it needs to be to maintain state across refreshes.

private MouseState _previousMouseState;
private bool _second;

protected override void Update(GameTime gameTime)
{
    var mouseState = Mouse.GetState();

    if(mouseState.LeftButton == ButtonState.Released && _previousMouseState.LeftButton == ButtonState.Pressed)
    {
        _second = !_second;
    }

    _previousMouseState = mouseState;

    base.Update(gameTime);
}

Since you're essentially just flipping a flag the if statement in the middle can be reduced to one line. Either way should work though.