CurrentCellDirtyStateChanged在更改单元格之前和之后给我.为什么?

我正试图通过使用CurrentCellDirtyStateChanged事件来捕获数据网格视图中所做的更改。当用户更改数据网格视图中的单元格时，我会捕获"之前"图像并将其保存到List。问题是，不知怎么的，我的代码将before和after图像都添加到了我的列表中，所以我最终得到了两个条目。当我完成调试时，程序似乎正在执行我的方法的最后三条语句两次。我做错什么了吗？这是我的代码：

    private void dataGridView1_CurrentCellDirtyStateChanged(object sender, EventArgs e)
    {
        // Create a list to hold before changes.
        changeList = new List<ChangeLogObject>();
        var beforeChange = new ChangeLogObject
        {
            UserName = Environment.UserName,
            TimeChanged = DateTime.Now,
            State = "Before",
            Mode = "Lesson",
            Hive = this.ddlHive.Text,
            Project = this.ddlProjects.Text,
            Mission = this.ddlMissions.Text,
            Module = this.ddlModules.Text,
            Course = this.ddlCourses.Text,
            Frame = (int)this.dataGridView1.CurrentRow.Cells[1].Value,
            LayerTitle = (string)this.dataGridView1.CurrentRow.Cells[2].Value,
            LayerText = (string)this.dataGridView1.CurrentRow.Cells[3].Value,
            GraphicNumber = (string)this.dataGridView1.CurrentRow.Cells[4].Value,
            Height = (int)this.dataGridView1.CurrentRow.Cells[5].Value,
            Width = (int)this.dataGridView1.CurrentRow.Cells[6].Value,
            X = (int)this.dataGridView1.CurrentRow.Cells[7].Value,
            Y = (int)this.dataGridView1.CurrentRow.Cells[8].Value
        };
        this.dataGridView1.CommitEdit(DataGridViewDataErrorContexts.Commit);
        this.dataGridView1.EndEdit();
        this.changeList.Add(beforeChange);
    }