DataView.RowStateFilter DataView.RowStateFilter DataView.RowStateFilter DataView.RowStateFilter Property

Definizione

Ottiene o imposta il filtro di stato della riga usato nell'oggetto DataView.Gets or sets the row state filter used in the DataView.

public:
 property System::Data::DataViewRowState RowStateFilter { System::Data::DataViewRowState get(); void set(System::Data::DataViewRowState value); };
[System.Data.DataSysDescription("DataViewRowStateFilterDescr")]
public System.Data.DataViewRowState RowStateFilter { get; set; }
member this.RowStateFilter : System.Data.DataViewRowState with get, set
Public Property RowStateFilter As DataViewRowState

Valore della proprietà

Esempi

Nell'esempio seguente viene creato DataTable un oggetto con una singola colonna, quindi vengono modificati i dati e RowStateFilter viene impostato DataView il valore di per visualizzare set di righe diversi, DataViewRowStatea seconda dell'oggetto.The following example creates a DataTable with a single column, and then changes the data and sets the RowStateFilter of the DataView to display different row sets, depending on the DataViewRowState.

static private void DemonstrateRowState()
{
    // Create a DataTable with one column.
    DataTable dataTable = new DataTable("dataTable");
    DataColumn dataColumn = new DataColumn("dataColumn");
    dataTable.Columns.Add(dataColumn);

    // Add ten rows.
    DataRow dataRow;
    for (int i = 0; i < 10; i++)
    {
        dataRow = dataTable.NewRow();
        dataRow["dataColumn"] = "item " + i;
        dataTable.Rows.Add(dataRow);
    }
    dataTable.AcceptChanges();

    // Create a DataView with the table.
    DataView dataView = new DataView(dataTable);

    // Change one row's value:
    dataTable.Rows[1]["dataColumn"] = "Hello";

    // Add one row:
    dataRow = dataTable.NewRow();
    dataRow["dataColumn"] = "World";
    dataTable.Rows.Add(dataRow);

    // Set the RowStateFilter to display only added and modified rows.
    dataView.RowStateFilter = DataViewRowState.Added
        | DataViewRowState.ModifiedCurrent;

    // Print those rows. Output = "Hello" "World";
    PrintView(dataView, "ModifiedCurrent and Added");

    // Set filter to display on originals of modified rows.
    dataView.RowStateFilter = DataViewRowState.ModifiedOriginal;
    PrintView(dataView, "ModifiedOriginal");

    // Delete three rows.
    dataTable.Rows[1].Delete();
    dataTable.Rows[2].Delete();
    dataTable.Rows[3].Delete();

    // Set the RowStateFilter to display only Added and modified rows.
    dataView.RowStateFilter = DataViewRowState.Deleted;
    PrintView(dataView, "Deleted");

    //Set filter to display only current.
    dataView.RowStateFilter = DataViewRowState.CurrentRows;
    PrintView(dataView, "Current");

    // Set filter to display only unchanged rows.
    dataView.RowStateFilter = DataViewRowState.Unchanged;
    PrintView(dataView, "Unchanged");

    // Set filter to display only original rows.
    dataView.RowStateFilter = DataViewRowState.OriginalRows;
    PrintView(dataView, "OriginalRows");
}


static private void PrintView(DataView dataView, string label)
{
    Console.WriteLine("\n" + label);
    for (int i = 0; i < dataView.Count; i++)
    {
        Console.WriteLine(dataView[i]["dataColumn"]);
    }
}
Private Sub DemonstrateRowState()
    Dim i As Integer

    ' Create a DataTable with one column.
    Dim dataTable As New DataTable("dataTable")
    Dim dataColumn As New DataColumn("dataColumn")
    dataTable.Columns.Add(dataColumn)

    ' Add ten rows.
    Dim dataRow As DataRow
    For i = 0 To 9
        dataRow = dataTable.NewRow()
        dataRow("dataColumn") = "item " + i.ToString()
        dataTable.Rows.Add(dataRow)
    Next i
    dataTable.AcceptChanges()

    ' Create a DataView with the table.
    Dim dataView As New DataView(dataTable)

    ' Change one row's value:
    dataTable.Rows(1)("dataColumn") = "Hello"

    ' Add one row:
    dataRow = dataTable.NewRow()
    dataRow("dataColumn") = "World"
    dataTable.Rows.Add(dataRow)

    ' Set the RowStateFilter to display only Added and modified rows.
    dataView.RowStateFilter = _
    DataViewRowState.Added Or DataViewRowState.ModifiedCurrent

    ' Print those rows. Output = "Hello" "World";
    PrintView(dataView, "ModifiedCurrent and Added")

    ' Set filter to display on originals of modified rows.
    dataView.RowStateFilter = DataViewRowState.ModifiedOriginal
    PrintView(dataView, "ModifiedOriginal")

    ' Delete three rows.
    dataTable.Rows(1).Delete()
    dataTable.Rows(2).Delete()
    dataTable.Rows(3).Delete()

    ' Set the RowStateFilter to display only Added and modified rows.
    dataView.RowStateFilter = DataViewRowState.Deleted
    PrintView(dataView, "Deleted")

    'Set filter to display only current.
    dataView.RowStateFilter = DataViewRowState.CurrentRows
    PrintView(dataView, "Current")

    ' Set filter to display only unchanged rows.
    dataView.RowStateFilter = DataViewRowState.Unchanged
    PrintView(dataView, "Unchanged")

    ' Set filter to display only original rows.
    dataView.RowStateFilter = DataViewRowState.OriginalRows
    PrintView(dataView, "OriginalRows")
End Sub

Private Sub PrintView(ByVal dataView As DataView, ByVal label As String)
    Console.WriteLine(ControlChars.Cr + label)
    Dim i As Integer
    For i = 0 To dataView.Count - 1
        Console.WriteLine(dataView(i)("dataColumn"))
    Next i
End Sub

Commenti

Solo le righe che sono state eliminate tramite Delete il metodo avranno RowStateFilter il valore impostato su Deleted.Only rows that have been deleted by using the Delete method will have their RowStateFilter value set to Deleted. Per le righe aggiunte utilizzando AddNew il metodo, la proprietà viene impostata su Added.Those rows added using the AddNew method will similarly have the property set to Added.

Nota

L'utilizzo Remove del metodo DataRowCollection della classe non significa che una riga verrà contrassegnata come Deleted.Using the Remove method of the DataRowCollection class does not mean that a row will be marked as Deleted. Usare invece Delete il metodo per assicurarsi che tali righe possano essere visualizzate DataViewin.Use the Delete method instead to make sure that such rows can be viewed in the DataView.

Le nuove righe saranno visibili anche quando l' RowStateFilter oggetto è impostato ModifiedCurrent su CurrentRowso.New rows will also be visible when the RowStateFilter is set to ModifiedCurrent or CurrentRows.

Le righe eliminate saranno visibili anche quando RowStateFilter l'oggetto è ModifiedOriginal impostato OriginalRowssu e.Deleted rows will also be visible when the RowStateFilter is set to ModifiedOriginal and OriginalRows.

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