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我正在尝试编辑DataTable填充NpgsqlDataAdapter.在调用Fill()方法之后,我只有一行DataTable.然后我只更改了一列的值,并尝试更新如下.

然后我收到这个错误:

发生了DBConcurrencyException

我的代码是:

NpgsqlDataAdapter getAllData = new NpgsqlDataAdapter("SELECT sn,
code,product, unitprice, quantity, InvoiceNo, Date FROM stocktable WHERE Code='" + product + "'
 ORDER BY EDate ASC", DatabaseConnectionpg);
DataTable ds1 = new DataTable();
ds1.Clear();
getAllData.Fill(ds1);

if (ds1.Rows.Count > 0)
{
    ds1.Rows[0]["Quantity"] = qty;// calculated value
}
ds1 = ds1.GetChanges();

NpgsqlCommandBuilder cb = new NpgsqlCommandBuilder(getAllData);
//getAllData.RowUpdating += (sender2, e2) => { e2.Command.Parameters.Clear(); };
//cb.SetAllValues = false;
getAllData.DeleteCommand = cb.GetDeleteCommand();
getAllData.InsertCommand = cb.GetInsertCommand();
getAllData.UpdateCommand …