DataTableReader 建構函式

定義

命名空間:

System.Data

組件:

System.Data.Common.dll

初始化 DataTableReader 類別的新執行個體。

多載

DataTableReader(DataTable)	使用所提供之 DataTableReader 的資料，初始化 DataTable 類別的新執行個體。
DataTableReader(DataTable[])	使用 DataTableReader 物件所提供的陣列，初始化 DataTable 類別的新執行個體。

DataTableReader(DataTable)

來源:

DataTableReader.cs

使用所提供之 DataTableReader 的資料，初始化 DataTable 類別的新執行個體。

public:
 DataTableReader(System::Data::DataTable ^ dataTable);

public DataTableReader (System.Data.DataTable dataTable);

new System.Data.DataTableReader : System.Data.DataTable -> System.Data.DataTableReader

Public Sub New (dataTable As DataTable)

參數

dataTable

DataTable

DataTable，新的 DataTableReader 從中取得其結果集。

DataTableReader(DataTable[])

來源:

DataTableReader.cs

使用 DataTableReader 物件所提供的陣列，初始化 DataTable 類別的新執行個體。

public:
 DataTableReader(cli::array <System::Data::DataTable ^> ^ dataTables);

public DataTableReader (System.Data.DataTable[] dataTables);

new System.Data.DataTableReader : System.Data.DataTable[] -> System.Data.DataTableReader

Public Sub New (dataTables As DataTable())

參數

dataTables

DataTable[]

DataTable 物件的陣列，該物件可以為新的 DataTableReader 物件提供結果。

範例

在下列範例中，TestConstructor 方法會建立兩 DataTable 個實例。 為了示範 類別的DataTableReader這個建構函式，此範例會根據包含兩DataTables個的陣列建立新的 DataTableReader ，並執行簡單的作業，將前幾個數據行的內容列印到控制台視窗。 若要測試此應用程式，請建立新的控制台應用程式，並將範例程式代碼貼到新建立的檔案中。

private static void TestConstructor()
{
    // Create two data adapters, one for each of the two
    // DataTables to be filled.
    DataTable customerDataTable = GetCustomers();
    DataTable productDataTable = GetProducts();

    // Create the new DataTableReader.
    using (DataTableReader reader = new DataTableReader(
               new DataTable[] { customerDataTable, productDataTable }))
    {
        // Print the contents of each of the result sets.
        do
        {
            PrintColumns(reader);
        } while (reader.NextResult());
    }

    Console.WriteLine("Press Enter to finish.");
    Console.ReadLine();
}

private static DataTable GetCustomers()
{
    // Create sample Customers table, in order
    // to demonstrate the behavior of the DataTableReader.
    DataTable table = new DataTable();

    // Create two columns, ID and Name.
    DataColumn idColumn = table.Columns.Add("ID", typeof(int));
    table.Columns.Add("Name", typeof(string ));

    // Set the ID column as the primary key column.
    table.PrimaryKey = new DataColumn[] { idColumn };

    table.Rows.Add(new object[] { 1, "Mary" });
    table.Rows.Add(new object[] { 2, "Andy" });
    table.Rows.Add(new object[] { 3, "Peter" });
    table.Rows.Add(new object[] { 4, "Russ" });
    return table;
}

private static DataTable GetProducts()
{
    // Create sample Products table, in order
    // to demonstrate the behavior of the DataTableReader.
    DataTable table = new DataTable();

    // Create two columns, ID and Name.
    DataColumn idColumn = table.Columns.Add("ID", typeof(int));
    table.Columns.Add("Name", typeof(string ));

    // Set the ID column as the primary key column.
    table.PrimaryKey = new DataColumn[] { idColumn };

    table.Rows.Add(new object[] { 1, "Wireless Network Card" });
    table.Rows.Add(new object[] { 2, "Hard Drive" });
    table.Rows.Add(new object[] { 3, "Monitor" });
    table.Rows.Add(new object[] { 4, "CPU" });
    return table;
}

private static void PrintColumns(DataTableReader reader)
{
    // Loop through all the rows in the DataTableReader
    while (reader.Read())
    {
        for (int i = 0; i < reader.FieldCount; i++)
        {
            Console.Write(reader[i] + " ");
        }
        Console.WriteLine();
    }
}

Private Sub TestConstructor()
   ' Create two data adapters, one for each of the two
   ' DataTables to be filled.
   Dim customerDataTable As DataTable = GetCustomers()
   Dim productDataTable As DataTable = GetProducts()

   ' Create the new DataTableReader.
   Using reader As New DataTableReader( _
      New DataTable() {customerDataTable, productDataTable})

      ' Print the contents of each of the result sets.
      Do
         PrintColumns(reader)
      Loop While reader.NextResult()
   End Using

   Console.WriteLine("Press Enter to finish.")
   Console.ReadLine()

End Sub

Private Function GetCustomers() As DataTable
   ' Create sample Customers table, in order
   ' to demonstrate the behavior of the DataTableReader.
   Dim table As New DataTable

   ' Create two columns, ID and Name.
   Dim idColumn As DataColumn = table.Columns.Add("ID", _
     GetType(Integer))
   table.Columns.Add("Name", GetType(String))

   ' Set the ID column as the primary key column.
   table.PrimaryKey = New DataColumn() {idColumn}

   table.Rows.Add(New Object() {1, "Mary"})
   table.Rows.Add(New Object() {2, "Andy"})
   table.Rows.Add(New Object() {3, "Peter"})
   table.Rows.Add(New Object() {4, "Russ"})
   Return table
End Function

Private Function GetProducts() As DataTable
   ' Create sample Products table, in order
   ' to demonstrate the behavior of the DataTableReader.
   Dim table As New DataTable

   ' Create two columns, ID and Name.
   Dim idColumn As DataColumn = table.Columns.Add("ID", _
     GetType(Integer))
   table.Columns.Add("Name", GetType(String))

   ' Set the ID column as the primary key column.
   table.PrimaryKey = New DataColumn() {idColumn}

   table.Rows.Add(New Object() {1, "Wireless Network Card"})
   table.Rows.Add(New Object() {2, "Hard Drive"})
   table.Rows.Add(New Object() {3, "Monitor"})
   table.Rows.Add(New Object() {4, "CPU"})
   Return table
End Function

Private Sub PrintColumns( _
   ByVal reader As DataTableReader)

   ' Loop through all the rows in the DataTableReader.
   Do While reader.Read()
      For i As Integer = 0 To reader.FieldCount - 1
         Console.Write(reader(i).ToString() & " ")
      Next
      Console.WriteLine()
   Loop
End Sub

[主控台] 視窗會顯示下列結果：

1 Mary  
2 Andy  
3 Peter  
4 Russ  
1 Wireless Network Card  
2 Hard Drive  
3 Monitor  
4 CPU  

備註

如果您必須根據特定 DataSet內的所有或數據表子集建立 DataTableReader ，請呼叫 DataSet的 CreateDataReader 方法。 如果您想要根據不相關的實例群組DataTable建立新的DataTableReader實例，請使用這個建構函式。 如果其來源內的DataSet排序DataTables不符合您的需求，您也可以利用這個建構函式來重新排列 內的 DataTableReader排序。