HOW TO:给DataTable添加一自增列至首列

Author:水如烟

 

示例

         Dim  db  As   New  LzmTW.Data.AccessOleDbDatabase( " G:/OfficeNorthwind.mdb " )

         Dim  cm  As  DbCommand  =  db.CreateCommand( " Employees " )
        cm.Connection.Open()
         Dim  table  As  DataTable  =  cm.ExecuteReader.GetSchemaTable
        cm.Connection.Dispose()
        cm.Dispose()


         Dim  nowTable  As  DataTable  =  TableHelper.AddAutoIncreaseColumn(table,  " NO " ,  1 )

代码:

Public   Class  TableHelper
     Sub   New ()
     End Sub

     Public   Shared   Function  AddAutoIncreaseColumn( ByVal  table  As  DataTable,  ByVal  columnName  As   String ,  Optional   ByVal  seed  As   Integer   =   0 ,  Optional   ByVal  [ step ]  As   Integer   =   1 )  As  DataTable
         Dim  autoIncreaseColumn  As   New  DataColumn(columnName,  GetType ( Integer ))
         With  autoIncreaseColumn
            .AutoIncrement  =   True
            .AutoIncrementSeed  =  seed
            .AutoIncrementStep  =  [ step ]
            .ReadOnly  =   True
         End   With

         Dim  tmpTable  As  DataTable  =  table.Clone

        tmpTable.PrimaryKey = Nothing

         Dim  result  As   New  DataTable(table.TableName)

        result.Columns.Add(autoIncreaseColumn)

         Dim  tmpCol  As  DataColumn
         For   Each  col  As  DataColumn  In  table.Columns
            tmpCol  =  tmpTable.Columns(col.ColumnName)
            tmpTable.Columns.Remove(tmpCol)
            result.Columns.Add(tmpCol)
         Next

        result.Merge(table)

         Return  result
     End Function
End Class