public bool Active
{
    get => active; //<---------there's a problem here-----
    set
    {
        if (active == false && value == true)
            Activate();
        else if (active == true && value == false)
            Suspend();

        active = value;
    }
}

CodePudding user response：

You don't have any variable declared called "active".

Declare one:

private bool active;

then

public bool Active
{
    get => active;
    set
    {
        if (active == false && value == true)
            Activate();
        else if (active == true && value == false)
            Suspend();

        active = value;
    }
}

To know more about c# properties read here.

CodePudding user response：

in C#4.0 you need write get{ return xxx; }

    bool active;
    public bool Active
    {
        get { return active; } //<---------there's a problem here----- 
        set
        {
            if (active == false && value == true)
                Activate();
            else if (active == true && value == false)
                Suspend();

            active = value;
        }
    }