DataSet.CreateDataReader Méthode
Définition
Important
Certaines informations portent sur la préversion du produit qui est susceptible d’être en grande partie modifiée avant sa publication. Microsoft exclut toute garantie, expresse ou implicite, concernant les informations fournies ici.
Retourne un DataTableReader avec un jeu de résultats par DataTable, dans la même séquence que les tables dans la collection Tables.
Surcharges
| CreateDataReader(DataTable[]) |
Retourne un DataTableReader avec un jeu de résultats par DataTable. |
| CreateDataReader() |
Retourne un DataTableReader avec un jeu de résultats par DataTable, dans la même séquence que les tables dans la collection Tables. |
Exemples
Cet exemple, une application Console, crée trois DataTable instances et ajoute chacune à un DataSet. L’exemple appelle la CreateDataReader méthode et affiche le contenu du retourné DataTableReader. Notez que l’ordre des jeux de résultats dans le DataTableReader est contrôlé par l’ordre des DataTable instances passées en tant que paramètres.
Notes
Cet exemple montre comment utiliser l’une des versions surchargées de CreateDataReader. Pour obtenir d’autres exemples qui peuvent être disponibles, consultez les rubriques de surcharge individuelles.
static DataTable customerTable;
static DataTable productTable;
static DataTable emptyTable;
static void Main()
{
DataSet dataSet = new DataSet();
// Add some DataTables to the DataSet, including
// an empty DataTable:
emptyTable = new DataTable();
productTable = GetProducts();
customerTable = GetCustomers();
dataSet.Tables.Add(customerTable);
dataSet.Tables.Add(emptyTable);
dataSet.Tables.Add(productTable);
TestCreateDataReader(dataSet);
Console.WriteLine("Press any key to continue.");
Console.ReadKey();
}
private static void TestCreateDataReader(DataSet dataSet)
{
// Given a DataSet, retrieve a DataTableReader
// allowing access to all the DataSet's data.
// Even though the dataset contains three DataTables,
// this code will only display the contents of two of them,
// because the code has limited the results to the
// DataTables stored in the tables array. Because this
// parameter is declared using the ParamArray keyword,
// you could also include a list of DataTable instances
// individually, as opposed to supplying an array of
// DataTables, as in this example:
using (DataTableReader reader =
dataSet.CreateDataReader(productTable, emptyTable))
{
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" });
table.AcceptChanges();
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" });
table.AcceptChanges();
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 emptyTable As DataTable
Private customerTable As DataTable
Private productTable As DataTable
Sub Main()
Dim dataSet As New DataSet
' Add some DataTables to the DataSet, including
' an empty DataTable:
emptyTable = New DataTable()
productTable = GetProducts()
customerTable = GetCustomers()
dataSet.Tables.Add(customerTable)
dataSet.Tables.Add(emptyTable)
dataSet.Tables.Add(productTable)
TestCreateDataReader(dataSet)
Console.WriteLine("Press any key to continue.")
Console.ReadKey()
End Sub
Private Sub TestCreateDataReader(ByVal dataSet As DataSet)
' Given a DataSet, retrieve a DataTableReader
' allowing access to all the DataSet's data.
' Even though the dataset contains three DataTables,
' this code will only display the contents of two of them,
' because the code has limited the results to the
' DataTables stored in the tables array. Because this
' parameter is declared using the ParamArray keyword,
' you could also include a list of DataTable instances
' individually, as opposed to supplying an array of
' DataTables, as in this example:
Using reader As DataTableReader = _
dataSet.CreateDataReader(productTable, emptyTable)
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"})
table.AcceptChanges()
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"})
table.AcceptChanges()
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
L’exemple montre comment afficher le code suivant dans la fenêtre Console :
Remarques
Afin de garantir l’ordre des jeux de résultats dans le retourné DataTableReader, si un DataTable dans le DataSet est vide, il sera représenté par un jeu de résultats vide dans le retourné DataTableReader.
CreateDataReader(DataTable[])
- Source:
- DataSet.cs
- Source:
- DataSet.cs
- Source:
- DataSet.cs
Retourne un DataTableReader avec un jeu de résultats par DataTable.
public:
System::Data::DataTableReader ^ CreateDataReader(... cli::array <System::Data::DataTable ^> ^ dataTables);public System.Data.DataTableReader CreateDataReader (params System.Data.DataTable[] dataTables);member this.CreateDataReader : System.Data.DataTable[] -> System.Data.DataTableReaderPublic Function CreateDataReader (ParamArray dataTables As DataTable()) As DataTableReaderParamètres
- dataTables
- DataTable[]
Tableau de DataTables qui fournit l'ordre des jeux de résultats à retourner dans le DataTableReader.
Retours
DataTableReader contenant un ou plusieurs jeux de résultats, correspondant aux instances de DataTable, contenues dans le DataSet source. Les jeux de résultats retournés sont dans l'ordre spécifié par le paramètre dataTables.
Exemples
Cet exemple, une application Console, crée trois DataTable instances et ajoute chacune à un DataSet. L’exemple appelle la CreateDataReader méthode et affiche le contenu du retourné DataTableReader. Notez que l’ordre des jeux de résultats dans le DataTableReader est contrôlé par l’ordre des DataTable instances passées en tant que paramètres. L’exemple montre comment afficher les résultats dans la fenêtre Console.
static DataTable customerTable;
static DataTable productTable;
static DataTable emptyTable;
static void Main()
{
DataSet dataSet = new DataSet();
// Add some DataTables to the DataSet, including
// an empty DataTable:
emptyTable = new DataTable();
productTable = GetProducts();
customerTable = GetCustomers();
dataSet.Tables.Add(customerTable);
dataSet.Tables.Add(emptyTable);
dataSet.Tables.Add(productTable);
TestCreateDataReader(dataSet);
Console.WriteLine("Press any key to continue.");
Console.ReadKey();
}
private static void TestCreateDataReader(DataSet dataSet)
{
// Given a DataSet, retrieve a DataTableReader
// allowing access to all the DataSet's data.
// Even though the dataset contains three DataTables,
// this code will only display the contents of two of them,
// because the code has limited the results to the
// DataTables stored in the tables array. Because this
// parameter is declared using the ParamArray keyword,
// you could also include a list of DataTable instances
// individually, as opposed to supplying an array of
// DataTables, as in this example:
using (DataTableReader reader =
dataSet.CreateDataReader(productTable, emptyTable))
{
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 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 emptyTable As DataTable
Private customerTable As DataTable
Private productTable As DataTable
Sub Main()
Dim dataSet As New DataSet
' Add some DataTables to the DataSet, including
' an empty DataTable:
emptyTable = New DataTable()
productTable = GetProducts()
customerTable = GetCustomers()
dataSet.Tables.Add(customerTable)
dataSet.Tables.Add(emptyTable)
dataSet.Tables.Add(productTable)
TestCreateDataReader(dataSet)
Console.WriteLine("Press any key to continue.")
Console.ReadKey()
End Sub
Private Sub TestCreateDataReader(ByVal dataSet As DataSet)
' Given a DataSet, retrieve a DataTableReader
' allowing access to all the DataSet's data.
' Even though the dataset contains three DataTables,
' this code will only display the contents of two of them,
' because the code has limited the results to the
' DataTables stored in the tables array. Because this
' parameter is declared using the ParamArray keyword,
' you could also include a list of DataTable instances
' individually, as opposed to supplying an array of
' DataTables, as in this example:
Using reader As DataTableReader = _
dataSet.CreateDataReader(productTable, emptyTable)
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 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
Remarques
Pour garantir que l’ordre des résultats est défini dans le retourné DataTableReader, si un DataTable dans le DataSet est vide, il est représenté par un jeu de résultats vide dans le retourné DataTableReader. Étant donné que cette version surchargée vous permet de fournir une liste d’instances DataTable en tant que paramètres, vous pouvez spécifier l’ordre dans lequel les jeux de résultats apparaissent dans le .DataTableReader
Voir aussi
S’applique à
CreateDataReader()
- Source:
- DataSet.cs
- Source:
- DataSet.cs
- Source:
- DataSet.cs
Retourne un DataTableReader avec un jeu de résultats par DataTable, dans la même séquence que les tables dans la collection Tables.
public:
System::Data::DataTableReader ^ CreateDataReader();public System.Data.DataTableReader CreateDataReader ();member this.CreateDataReader : unit -> System.Data.DataTableReaderPublic Function CreateDataReader () As DataTableReaderRetours
DataTableReader contenant un ou plusieurs jeux de résultats, correspondant aux instances de DataTable, contenues dans le DataSet source.
Exemples
L’exemple suivant crée trois DataTable instances et ajoute chacune à un DataSet. L’exemple passe ensuite le rempli DataSet à une procédure qui appelle la CreateDataReader méthode et continue à itérer à travers tous les jeux de résultats contenus dans .DataTableReader L’exemple montre comment afficher les résultats dans la fenêtre Console.
static void Main()
{
DataSet dataSet = new DataSet();
// Add some DataTables to the DataSet, including
// an empty DataTable:
dataSet.Tables.Add(GetCustomers());
dataSet.Tables.Add(new DataTable());
dataSet.Tables.Add(GetProducts());
TestCreateDataReader(dataSet);
Console.WriteLine("Press any key to continue.");
Console.ReadKey();
}
private static void TestCreateDataReader(DataSet dataSet)
{
// Given a DataSet, retrieve a DataTableReader
// allowing access to all the DataSet's data:
using (DataTableReader reader = dataSet.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 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();
}
}
Sub Main()
Dim dataSet As New DataSet
' Add some DataTables to the DataSet, including
' an empty DataTable:
dataSet.Tables.Add(GetCustomers())
dataSet.Tables.Add(New DataTable())
dataSet.Tables.Add(GetProducts())
TestCreateDataReader(dataSet)
Console.WriteLine("Press any key to continue.")
Console.ReadKey()
End Sub
Private Sub TestCreateDataReader(ByVal dataSet As DataSet)
' Given a DataSet, retrieve a DataTableReader
' allowing access to all the DataSet's data:
Using reader As DataTableReader = dataSet.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 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
Remarques
Afin de garantir l’ordre des jeux de résultats dans le retourné DataTableReader, si un DataTable dans est DataSet vide, il est représenté par un jeu de résultats vide dans le retourné DataTableReader.
Voir aussi
S’applique à
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