使用 DbDataAdapter 修改資料

發行項
03/04/2024

CreateDataAdapter 物件的 DbProviderFactory 方法可提供 DbDataAdapter 物件，而它是建立 Factory 時指定之基礎資料提供者的強型別 (Strongly Typed) 物件。然後，您可以使用 DbCommandBuilder 來建立命令，以便針對資料來源插入、更新和刪除 DataSet 的資料。

使用 DbDataAdapter 擷取資料

這則範例將示範如何根據提供者名稱和連接字串 (Connection String) 來建立強型別 DbDataAdapter。此程式碼會使用 CreateConnection 的 DbProviderFactory 方法來建立 DbConnection。接著，此程式碼會使用 CreateCommand 方法來建立 DbCommand，以便透過設定其 CommandText 和 Connection 屬性來選取資料。最後，此程式碼會使用 DbDataAdapter 方法來建立 CreateDataAdapter 物件並設定其 SelectCommand 屬性。 Fill 的 DbDataAdapter 方法會將資料載入 DataTable 中。

static void CreateDataAdapter(string providerName, string connectionString)
{
    try
    {
        // Create the DbProviderFactory and DbConnection.
        DbProviderFactory factory =
            DbProviderFactories.GetFactory(providerName);

        DbConnection connection = factory.CreateConnection();
        connection.ConnectionString = connectionString;

        using (connection)
        {
            // Define the query.
            const string queryString =
                "SELECT CategoryName FROM Categories";

            // Create the DbCommand.
            DbCommand command = factory.CreateCommand();
            command.CommandText = queryString;
            command.Connection = connection;

            // Create the DbDataAdapter.
            DbDataAdapter adapter = factory.CreateDataAdapter();
            adapter.SelectCommand = command;

            // Fill the DataTable.
            DataTable table = new();
            adapter.Fill(table);

            //  Display each row and column value.
            foreach (DataRow row in table.Rows)
            {
                foreach (DataColumn column in table.Columns)
                {
                    Console.WriteLine(row[column]);
                }
            }
        }
    }
    catch (Exception ex)
    {
        Console.WriteLine(ex.Message);
    }
}

Shared Sub CreateDataAdapter(ByVal providerName As String, _
    ByVal connectionString As String)

    ' Create the DbProviderFactory and DbConnection.
    Try
        Dim factory As DbProviderFactory = _
           DbProviderFactories.GetFactory(providerName)

        Dim connection As DbConnection = _
            factory.CreateConnection()
        connection.ConnectionString = connectionString
        Using connection

            ' Define the query.
            Dim queryString As String = _
              "SELECT CategoryName FROM Categories"

            'Create the DbCommand.
            Dim command As DbCommand = _
                factory.CreateCommand()
            command.CommandText = queryString
            command.Connection = connection

            ' Create the DbDataAdapter.
            Dim adapter As DbDataAdapter = _
                factory.CreateDataAdapter()
            adapter.SelectCommand = command

            ' Fill the DataTable
            Dim table As New DataTable
            adapter.Fill(table)

            'Display each row and column value.
            Dim row As DataRow
            Dim column As DataColumn
            For Each row In table.Rows
                For Each column In table.Columns
                    Console.WriteLine(row(column))
                Next
            Next
        End Using

    Catch ex As Exception
        Console.WriteLine(ex.Message)
    End Try
End Sub