VB.Net by API/System.Data/DataColumnMapping — различия между версиями

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Текущая версия на 12:49, 26 мая 2010

New DataColumnMapping

  

Imports System
Imports System.Xml
Imports System.Xml.Schema
Imports System.IO
Imports System.Data.OleDb
Imports System.Data.rumon
Imports System.Data

Public Class MainClass
    
    Shared Sub DoDataMappings(ByVal da As OleDbDataAdapter)
        Try
            " Define an array of column to map
            Dim dcmMappedColumns() As DataColumnMapping = { _
                      New DataColumnMapping("ID", "EmployeeID"), _
                      New DataColumnMapping("FirstName", "FirstName"), _
                      New DataColumnMapping("LastName", "LastName")}
            " Define the table containing the mapped columns
            Dim dtmUsers As New DataTableMapping("Table", "Employee", _
            dcmMappedColumns)
            " Activate the mapping mechanism
            da.TableMappings.Add(dtmUsers)
        Catch ex As Exception
            " An error occurred. Show the error message
            Console.WriteLine(ex.Message)
        End Try
    End Sub
    Shared Sub Main()
        Try
            " Define a connection object
            Dim dbConn As New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Password=;User ID=Admin;Data Source=Employee.mdb")
            " Create a data adapter to retrieve records from db
            Dim daUsers As New OleDbDataAdapter("SELECT ID, FirstName, LastName FROM Employee", dbConn)
            Dim dsUsers As New DataSet("Employee")
            DoDataMappings(daUsers)
            " Fill the dataset
            daUsers.Fill(dsUsers)
            " Go through the records and print them using the mapped names
            Dim r As DataRow
            For Each r In dsUsers.Tables("Employee").Rows
                Console.WriteLine("ID: {0}, FirstName: {1}, LastName: {2}", r("EmployeeID"), r("FirstName"), r("LastName"))
            Next
        Catch ex As Exception
            " An error occurred. Show the error message
            Console.WriteLine(ex.Message)
        End Try
    End Sub
End Class