How to increment the Auto Generated Id

Question

I'm pretty new to C#. I want to increment an int variable id by 1 and insert it into a datagridview. The problem is, it doesn't increment, it stays at 1.

Here's my code for adding the data to datagridview

class QuantityCtrl : Quantity
{
   private ManageSale _manageSale;

   public QuantityCtrl(ManageSale manageSale)
   {
        _manageSale = manageSale;
   }

   private void BtnOk_Click(object sender, EventArgs e)
   {
        _manageSale.dgvItemList.Rows.Add
        (
            GenerateId(),
            _manageSale.lblName.Text,
            _manageSale.lblPrice.Text,
            _manageQuantity.txtDiscount.Text,
            _manageQuantity.txtQuantity.Text,
            Total
        );
   }
}

Here's my code for incrementing

class Quantity
{
    public int OrderId = 1;

    public int GenerateId()
    {
        return OrderId++;
    }
}

Answer 1

I solved it thanks to Brendan. I hope it could be a referrence for some developers :) and If someone has a better way of incrementing you can answer it Thank you.

public static int OrderId = 1;

Answer 2

Another way of doing it would be creating a new class in a folder inside your solution which contains the list and the proprieties :

class IDS
{

    #region Proprieties
    public int Id { get; set; }
    #endregion

    #region Lists
    public List<IDS> _ids = new List<IDS>();
    #endregion
}

Now, you'll need to link the class to the main, for that, go in your main code and put at the top :

using SolutionName.Folder;

Next go to your button event and simply put this:

private void btnAutoGen_PreviewMouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
   int iId = 0;

   try
   {
       var req = (from value in _id
                  select value.Id).Max() + 1;
       iId = req;
   }
   catch (InvalidOperationException)
   {
       iId = 1;
   }

You now have a button that auto increment.