datagridview的文本将消失

我在项目中使用telerik控件（数据网格视图）。但当我想在数据网格中添加新行时，前几行的文本（bindingSourceService.DataSource=dtservice，bindingSourceUnit.DataSource=dtunit）会消失。我的datagridview有3个组合框列。怎么了？请帮帮我。

我的代码：

public void FactorLoad(object sender, EventArgs e)
        {
            try
            {
                var cb = new CategoriBll();
               DataTable dtcategori = cb.GetAllDataCategori();
               bindingSourceCategouri.DataSource = dtcategori;
            }
            catch (Exception ex)
            {
               ExceptionkeeperBll.LogFileWrite(ex);
            }
}
   private void DataGridViewFactorCellValueChanged(object sender, GridViewCellEventArgs e)
        {
            try
            {
                var row = DataGridViewFactor.CurrentRow;
                if ((row != null) && (row.Cells[0].IsCurrent))
                {
                    var categoryId = Convert.ToInt32(DataGridViewFactor.CurrentRow.Cells[0].Value);
                    var sb = new CategoriOptionBll();
                    DataTable dtservice = sb.ServiceGetById(categoryId);
                    bindingSourceService.DataSource = dtservice;
                }
                if ((row != null) && (row.Cells[1].IsCurrent))
                {
                    var serviceId = Convert.ToInt32(DataGridViewFactor.CurrentRow.Cells[1].Value);
                    var cbi = new CostBll();
                    var dtunit = cbi.CostById(serviceId);
                    bindingSourceUnit.DataSource = dtunit;
                }
            }
            catch (Exception ex)
            {
                ExceptionkeeperBll.LogFileWrite(ex);
            }
        }
        private void DataGridViewFactorCellEditorInitialized(object sender, GridViewCellEventArgs e)
        {
            try
            {
                var row = DataGridViewFactor.CurrentRow;
                if ((row != null) && (row.Cells[0].IsCurrent))
                {
                    var categoryId = Convert.ToInt32(DataGridViewFactor.CurrentRow.Cells[0].Value);
                    var sb = new CategoriOptionBll();
                    DataTable dtservice = sb.ServiceGetById(categoryId);
                    bindingSourceService.DataSource = dtservice;
                }
                if ((row != null) && (row.Cells[1].IsCurrent))
                {
                    var serviceId = Convert.ToInt32(DataGridViewFactor.CurrentRow.Cells[1].Value);
                    var cbi = new CostBll();
                    var dtunit = cbi.CostById(serviceId);
                    bindingSourceUnit.DataSource = dtunit;
                }
            }
            catch (Exception ex)
            {
                ExceptionkeeperBll.LogFileWrite(ex);
            }
        }