每次添加新行时都应该调用 AcceptChanges() 吗?

问题描述

推荐

while (reader.Read())
{
    table.Rows.Add(
            new object[] { reader[0], reader[1], reader[2], reader[3] }
    );
    table.AcceptChanges();
}

或

while (reader.Read())
{
    table.Rows.Add(
            new object[] { reader[0], reader[1], reader[2], reader[3] }
    );
}
table.AcceptChanges();

注意 table.AcceptChanges 的放置位置.

Note where the table.AcceptChanges is placed.

编辑 1

这里是代码块:

protected void Page_Load(object sender, EventArgs e)
{
    IDataReader reader = cust.GetCustomerOrderSummary("99999");
    using (DataSet ds = new DataSet())
    {
        using (DataTable table =
                new DataTable { TableName = "OrderSummary" })
        {
            DataColumn idColumn = table.Columns.Add("number", typeof(int));
            table.Columns.Add("name", typeof(string));
            table.Columns.Add("quantity", typeof(int));
            table.Columns.Add("prev_quantity", typeof(int));
            table.PrimaryKey = new DataColumn[] { idColumn };
            while (reader.Read())
            {
                table.Rows.Add(
                  new object[]{ reader[0], reader[1], reader[2], reader[3] }
                );
                table.AcceptChanges();
            }
            ds.Tables.Add(table);
            rptCustomerOrder report =
                    new rptCustomerOrder { DataSource = ds };
            ReportViewer1.Report = report;
        }
    }
}

编辑 2
在阅读了 MSDN 文章 here 我决定根据以下语句(来自文章)将 AcceptChanges() 置于循环之外:

---

EDIT 2
After reading the MSDN article here I decided to place the AcceptChanges() outside the loop based on the following statement (from the article):

在 DataTable 级别调用 AcceptChanges 会导致调用每个 DataRow 的 AcceptChanges 方法.

推荐答案

添加新行后调用AcceptChanges实际上会变成你新添加的DataRow的DataRowState 从 Added 到 Unchanged.如果您继续使用它，您可能失去对新添加行的跟踪，并且在持久化时.ADO.NET 无法识别需要插入数据库的行.所以明智地选择这个选项，你甚至可能不需要它.

Calling AcceptChanges after adding new row will actually turn the DataRowState of your newly added DataRow from Added to Unchanged. If you go with it you might lose the tracking of your newly added rows and at the time of persistance. ADO.NET would not be able to identify the rows which needs to be inserted in the database. So choose this option wisely you might not even require it.

这篇关于每次添加新行时都应该调用 AcceptChanges() 吗?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！