You are creating a DataTable. You use the following code segment to create the DataTable. (Line numbers are included for reference only.) 01 Dim dt As New DataTable("Products") 02 dt.Columns.Add(New DataColumn("Price", _ GetType(Decimal))) 03 dt.Columns.Add(New DataColumn("Quantity", _ GetType(Int32))) 04 Dim dc As DataColumn = New DataColumn("Total", _ GetType(Decimal)) 05 dt.Columns.Add(dc) You need to ensure that the Total column is set to the value of the Price column multiplied by the Quantity column when new rows are added or changed. What should you do? ()
在关于DataSet和DataTable的以下描述中,选出正确的答案。()
dataTable是数据集myDataSet中的数据表对象,有10条记录。调用下列代码后,dataTable中还有几条记录?()
You are creating a DataTable. You use the following code segment to create the DataTable. (Line numbers are included for reference only.) 01 DataTable dt = new DataTable(“Products”); 02 dt.Columns.Add(new DataColumn(“Price”, typeof(decimal))); 03 dt.Columns.Add(new DataColumn(“Quantity”, typeof(Int32))); 04 DataColumn dc = new DataColumn(“Total”, typeof(decimal)); 05 dt.Columns.Add(dc); You need to ensure that the Total column is set to the value of the Price column multiplied by the Quantity column when new rows are added or changed. What should you do? ()
DataTable类的()方法可以用来查询过滤数据。
一个()对象包含一组DataTable对象和DataRelation对象,其中每个DataTable对象都有DataColumn、DataRow组成。
以下语句执行后myTable的名称是()。 Dim myTable as DataTable myTable=New System.Data.DataTable()
DataTable类的()方法可以用来查询过滤数据。
DataTable有三种集合:()、()和()。
在基于非连接的环境,在创建了DataTable的数据集之后,如果需要修改记录,可以通过修改DataTable的Rows集合中的DataRow对象来修改记录。其步骤如下: 1)定位需要修改的行 2)调用BeginEdit方法开始编辑 3)对相应列值进行修改 4)调用EndEdit确认编辑或者CancelEdit取消编辑 5)执行Update方法更新数据源 6)调用AcceptChange方法接受更改 下面的代码将DataGrid1的当前行数据修改为指定的值。请根据程序代码中的注释将程序补充完整。