在已有数据后为 DataTable 设置自动编号 [英] Set autonumber for DataTable after it already has data

问题描述

我有以下代码将自动编号列添加到 DataTable:

I have the following code to add an autonumber column to a DataTable:

public void AddAutoIncrementColumn(DataTable dt)
{
   DataColumn column = new DataColumn();
   column.DataType = System.Type.GetType("System.Int32");
   column.AutoIncrement = true;
   column.AutoIncrementSeed = 0;
   column.AutoIncrementStep = 1;
   dt.Columns.Add(column);
}

但是，对于表中已经存在的所有行，此值将为空；似乎只有在添加此列后添加的新行才会触发 AutoIncrement.有没有办法为已经存在的行设置自动编号值?

However, this value will be blank for all rows that are already in the table; it seems that the AutoIncrement is only triggered for new rows that are added after this column has been added. Is there a way to set autonumber values for the rows that already exist?

推荐答案

我认为当行已经在表中时不可能触发 AutoIncrement 功能.但是您可以轻松地手动更新表格:

I don't think that it's possible to trigger the AutoIncrement functionality when the rows are already in the table. But you could update the table manually easily:

public void AddAutoIncrementColumn(DataTable dt)
{
    DataColumn column = new DataColumn();
    column.DataType = System.Type.GetType("System.Int32");
    column.AutoIncrement = true;
    column.AutoIncrementSeed = 0;
    column.AutoIncrementStep = 1;
    dt.Columns.Add(column);
    int index = -1;
    foreach (DataRow row in dt.Rows)
    {
        row.SetField(column, ++index);
    }
}

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