Dim tab As DataTable = myDB.GetTab("select * from Vrecords") Dim tmptab As New DataTable Dim tmpRow As DataRow tmptab.Columns.Add(New DataColumn("myHour", GetType(Integer))) tmptab.Columns.Add(New DataColumn("myCount", GetType(Long))) For i As Integer = 1 To 24 tmpRow = tmptab.NewRow tmpRow(0) = i Dim tmpFtrow As DataRow() = tab.Select("vhour=" & i) tmpRow(1) = tmpFtrow.Length Total += tmpFtrow.Length tmptab.Rows.Add(tmpRow) Next Datagrid1.DataSource = tmptab Datagrid1.DataBind()
Dim tmptab As New DataTable
Dim tmpRow As DataRow tmptab.Columns.Add(New DataColumn("myHour", GetType(Integer)))
tmptab.Columns.Add(New DataColumn("myCount", GetType(Long)))
For i As Integer = 1 To 24
tmpRow = tmptab.NewRow
tmpRow(0) = i
Dim tmpFtrow As DataRow() = tab.Select("vhour=" & i)
tmpRow(1) = tmpFtrow.Length
Total += tmpFtrow.Length
tmptab.Rows.Add(tmpRow)
Next Datagrid1.DataSource = tmptab
Datagrid1.DataBind()
DataSet中的表呀,恩----是直接选择的原表的所有列,不是部分列呀。
DataView 类
DataTable.Select 方法
R = DataTable.Select("a1=1 and a2 = 2")
http://www.microsoft.com/china/MSDN/library/data/dataAccess/ADONETEXP.mspx