DataTable.CreateDataReader 方法
重要
部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。
傳回對應於這個 DataTableReader 之中資料的 DataTable。
public:
System::Data::DataTableReader ^ CreateDataReader();C#
public System.Data.DataTableReader CreateDataReader ();member this.CreateDataReader : unit -> System.Data.DataTableReaderPublic Function CreateDataReader () As DataTableReaderDataTableReader，其中包含一個結果集，對應於來源 DataTable 執行個體。
下列的主控台應用程式會建立 DataTable 執行個體 (Instance)。 此範例接著會將填滿的 DataTable 傳遞至呼叫 CreateDataReader 方法的程序，而這個方法將逐一查看包含在 DataTableReader 內的結果。
C#
static void Main()
{
TestCreateDataReader(GetCustomers());
Console.WriteLine("Press any key to continue.");
Console.ReadKey();
}
private static void TestCreateDataReader(DataTable dt)
{
// Given a DataTable, retrieve a DataTableReader
// allowing access to all the tables' data:
using (DataTableReader reader = dt.CreateDataReader())
{
do
{
if (!reader.HasRows)
{
Console.WriteLine("Empty DataTableReader");
}
else
{
PrintColumns(reader);
}
Console.WriteLine("========================");
} while (reader.NextResult());
}
}
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 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();
}
}
Sub Main()
TestCreateDataReader(GetCustomers())
Console.WriteLine("Press any key to continue.")
Console.ReadKey()
End Sub
Private Sub TestCreateDataReader(ByVal dt As DataTable)
' Given a DataTable, retrieve a DataTableReader
' allowing access to all the tables's data:
Using reader As DataTableReader = dt.CreateDataReader()
Do
If Not reader.HasRows Then
Console.WriteLine("Empty DataTableReader")
Else
PrintColumns(reader)
End If
Console.WriteLine("========================")
Loop While reader.NextResult()
End Using
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 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
此範例會在主控台視窗中顯示以下輸出：
1 Mary
2 Andy
3 Peter
4 Russ
| 產品 | 版本 |
|---|---|
| .NET | Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9 |
| .NET Framework | 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1 |
| .NET Standard | 2.0, 2.1 |
