DataRow.Delete Metoda

Definice

DataRowOdstraní.Deletes the DataRow.

public:
 void Delete();
public void Delete ();
member this.Delete : unit -> unit
Public Sub Delete ()

Výjimky

DataRow Již byl odstraněn.The DataRow has already been deleted.

Příklady

Následující příklad vytvoří jednoduchý DataTable se dvěma sloupci a deseti řádky.The following example creates a simple DataTable with two columns and ten rows. Po odstranění několika DataRow položek Delete s metodou je jeden z řádků neodstraněn vyvoláním RejectChanges.After deleting several DataRow items with the Delete method, one of the rows is undeleted by invoking RejectChanges.

private void DemonstrateDeleteRow()
{
    // Create a simple DataTable with two columns and ten rows.
    DataTable table = new DataTable("table");
    DataColumn idColumn = new DataColumn("id",
        Type.GetType("System.Int32"));
    idColumn.AutoIncrement=true;
    DataColumn itemColumn = new DataColumn("item", 
        Type.GetType("System.String"));
    table.Columns.Add(idColumn);
    table.Columns.Add(itemColumn);

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

    DataRowCollection itemColumns = table.Rows;
    itemColumns[0].Delete();
    itemColumns[2].Delete();
    itemColumns[3].Delete();
    itemColumns[5].Delete();
    Console.WriteLine(itemColumns[3].RowState.ToString());

    // Reject changes on one deletion.
    itemColumns[3].RejectChanges();

    // Change the value of the column so it stands out.
    itemColumns[3]["item"] = "Deleted, Undeleted, Edited";

    // Accept changes on others.
    table.AcceptChanges();

    // Print the remaining row values.
    foreach(DataRow row in table.Rows)
    {
        Console.WriteLine(row[0] + "\table" + row[1]);
    }
}
 Private Sub DemonstrateDeleteRow()
     ' Create a simple DataTable with two columns and ten rows.
     Dim table As New DataTable("table")
     Dim idColumn As New DataColumn("id", Type.GetType("System.Int32"))
     idColumn.AutoIncrement = True
     Dim itemColumn As New DataColumn("item", Type.GetType("System.String"))
     table.Columns.Add(idColumn)
     table.Columns.Add(itemColumn)

     ' Add ten rows.
     Dim newRow As DataRow
     
     Dim i As Integer
     For i = 0 To 9
         newRow = table.NewRow()
         newRow("item") = "Item " & i.ToString()
         table.Rows.Add(newRow)
     Next i
     table.AcceptChanges()

     Dim itemColumns As DataRowCollection = table.Rows
     itemColumns(0).Delete()
     itemColumns(2).Delete()
     itemColumns(3).Delete()
     itemColumns(5).Delete()
     Console.WriteLine(itemColumns(3).RowState.ToString())

     ' Reject changes on one deletion.
     itemColumns(3).RejectChanges()

     ' Change the value of the column so it stands out.
     itemColumns(3)("item") = "Deleted, Undeleted, Edited"

     ' Accept changes on others.
     table.AcceptChanges()

     ' Print the remaining row values.
     Dim row As DataRow
     For Each row In  table.Rows
         Console.WriteLine(row(0).ToString() & ControlChars.Tab _
            & row(1).ToString())
     Next row
End Sub

Poznámky

Pokud je řádek přidán, Detached dojde k jeho RowState a při volání AcceptChangesse z tabulky odebere řádek. RowStateIf the RowState of the row is Added, the RowState becomes Detached and the row is removed from the table when you call AcceptChanges.

Po použití RowStatemetodyv existujícímDataRowrozhraní se zobrazí. Delete DeletedThe RowState becomes Deleted after you use the Delete method on an existing DataRow. Zůstane Deleted , dokud nebudete volat AcceptChanges.It remains Deleted until you call AcceptChanges. V tuto chvíli DataRow se odebere z tabulky.At this time, the DataRow is removed from the table.

Deleteby neměl být volán ve smyčce foreach při iteraci DataRowCollection objektu.Delete should not be called in a foreach loop while iterating through a DataRowCollection object. Deleteupraví stav kolekce.Delete modifies the state of the collection.

Odstraněné řádky lze obnovit vyvoláním RejectChanges.A deleted row can be undeleted by invoking RejectChanges.

Poznámka

BeginEdit Metoda dočasně RowChanging pozastaví události, ale operace odstranění nikoli.The BeginEdit method temporarily suspends RowChanging events, but the delete operation does not.

Platí pro

Viz také