How to change a specific datagridview column format

I have a datagridview which displays my records in currency format. I set the DefaultCellStyle property permanently for the format BUT I have a particular column which I wanna display it values as an Integer.

The column i wanna change and what it displays:

    [AreaCode]
     15,00 €
     25,00 €
     60,00 €

My expectation:

[AreaCode]
   15
   25
   60

And here is my code which isn't working:

private void dgv1_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
    {
  var columnname = "AreaCode";
   if (e.ColumnIndex == dgv1.Columns[columnname].Index)
        {
            //Get the datagridview cell
   DataGridViewCell cell = dgv1.Rows[e.RowIndex].Cells[e.ColumnIndex];
            if (cell != null)
            {
  this.dgv1.Columns["AreaCode"].DefaultCellStyle.Format = "D4";
            }

        }

    }

Thnx in advance