datagridview 不允许用户删除行

我有一个绑定到数据表的 datagridview。这些列不是自动生成的，我是在代码中创建的。我希望我的用户能够添加和删除行，因此我有AllowUserToAddRows = true，AllowUserToDeleteRows = true。

问题是：当他们选择一行并按 DEL 时，信息将被行单元格的默认值替换。行并没有消失。

这是什么行为（为什么/发生了什么），我该如何解决它？

这是我的网格创建代码：

    private void resetDowntimeGrid()
    {
        downtimeEntries = new DataTable();

        downtimeEntries.Columns.Add("Category", typeof(int));
        downtimeEntries.Columns.Add("HoursDown");
        downtimeEntries.Columns.Add("Reason");

        //deptDowntimeCategories.Select("", "ListOrder ASC");

        gridDowntime.Columns.Clear();

        DataGridViewComboBoxColumn cboCategory = new DataGridViewComboBoxColumn();
        {
            cboCategory.HeaderText = "Category";
            cboCategory.DataSource = deptDowntimeCategories;
            cboCategory.DisplayMember = "Name";
            cboCategory.ValueMember = "CategoryID";
            cboCategory.DataPropertyName = "Category";
            cboCategory.Width = Convert.ToInt16(gridDowntime.Width * 0.20);
            cboCategory.DisplayStyle = DataGridViewComboBoxDisplayStyle.ComboBox;
            cboCategory.AutoComplete = true;

            gridDowntime.Columns.Add(cboCategory);
        }

        DataGridViewTextBoxColumn txtDowntime = new DataGridViewTextBoxColumn();
        txtDowntime.HeaderText = "HoursDown";
        txtDowntime.DataPropertyName = "HoursDown";
        txtDowntime.Width = Convert.ToInt16(gridDowntime.Width * 0.15);
        gridDowntime.Columns.Add(txtDowntime);

        DataGridViewTextBoxColumn txtReason = new DataGridViewTextBoxColumn();
        txtReason.HeaderText = "Reason";
        txtReason.DataPropertyName = "Reason";
        txtReason.Width = Convert.ToInt16(gridDowntime.Width * 0.60);
        gridDowntime.Columns.Add(txtReason);

        gridDowntime.DataSource = downtimeEntries;

        lblStatus.Text = "Downtime grid reset.";
    }

我创建了一个空的winform，然后将网格代码放入其中。不同之处在于我的方式DataGridView.EditMode放。我有它= EditOnEnter，但是如果我设置它，删除效果会很好= EditOnKeystroke.