DataRowVersion Enum

Definition

Popisuje verzi DataRow.Describes the version of a DataRow.

public enum class DataRowVersion
public enum DataRowVersion
type DataRowVersion = 
Public Enum DataRowVersion
Inheritance
DataRowVersion

Fields

Current 512

Řádek obsahuje aktuální hodnoty.The row contains current values.

Default 1536

Výchozí verze DataRowState.The default version of DataRowState. V případě DataRowState hodnoty Added, Modified nebo Deletedje výchozí verze Current.For a DataRowState value of Added, Modified or Deleted, the default version is Current. U DataRowState hodnoty Detachedje verze Proposed.For a DataRowState value of Detached, the version is Proposed.

Original 256

Řádek obsahuje původní hodnoty.The row contains its original values.

Proposed 1024

Řádek obsahuje navrhovanou hodnotu.The row contains a proposed value.

Examples

Následující příklad zkontroluje DataRowVersion DataRow před vyvoláním metody AcceptChanges.The following example checks the DataRowVersion of a DataRow before invoking the AcceptChanges method.

private static void CheckVersionBeforeAccept()
{
    //Run a function to create a DataTable with one column.
    DataTable dataTable = MakeTable();

    DataRow dataRow = dataTable.NewRow();
    dataRow["FirstName"] = "Marcy";
    dataTable.Rows.Add(dataRow);

    dataRow.BeginEdit();
    // Edit data but keep the same value.
    dataRow[0] = "Marcy";
    // Uncomment the following line to add a new value.
    // dataRow(0) = "Richard"
    Console.WriteLine(string.Format("FirstName {0}", dataRow[0]));

    // Compare the proposed version with the current.
    if (dataRow.HasVersion(DataRowVersion.Proposed)) {
        if (object.ReferenceEquals(dataRow[0, DataRowVersion.Current], dataRow[0, DataRowVersion.Proposed])) {
            Console.WriteLine("The original and the proposed are the same.");
            dataRow.CancelEdit();
        } else {
            dataRow.AcceptChanges();
            Console.WriteLine("The original and the proposed are different.");
        }
    }
}

private static DataTable MakeTable()
{
    // Make a simple table with one column.
    DataTable dt = new DataTable("dataTable");
    DataColumn firstName = new DataColumn("FirstName", Type.GetType("System.String"));
    dt.Columns.Add(firstName);
    return dt;
}
Private Sub CheckVersionBeforeAccept()
    'Run a function to create a DataTable with one column.
    Dim dataTable As DataTable = MakeTable()

    Dim dataRow As DataRow = dataTable.NewRow()
    dataRow("FirstName") = "Marcy"
    dataTable.Rows.Add(dataRow)

    dataRow.BeginEdit()
    ' Edit data but keep the same value.
    dataRow(0) = "Marcy"
    ' Uncomment the following line to add a new value.
    ' dataRow(0) = "Richard"
    Console.WriteLine(String.Format("FirstName {0}", dataRow(0)))

    ' Compare the proposed version with the current.
    If dataRow.HasVersion(DataRowVersion.Proposed) Then
        If dataRow(0, DataRowVersion.Current) Is dataRow(0, DataRowVersion.Proposed) Then
            Console.WriteLine("The original and the proposed are the same.")
            dataRow.CancelEdit()
        Else
            dataRow.AcceptChanges()
            Console.WriteLine("The original and the proposed are different.")
        End If
    End If
End Sub

Private Function MakeTable() As DataTable
    ' Make a simple table with one column.
    Dim dt As New DataTable("dataTable")
    Dim firstName As New DataColumn("FirstName", _
       Type.GetType("System.String"))
    dt.Columns.Add(firstName)
    Return dt
End Function

Remarks

Hodnoty DataRowVersion se používají při načítání hodnoty nalezené v DataRow pomocí Item[] nebo GetChildRows objektu DataRow.The DataRowVersion values are used when retrieving the value found in a DataRow using Item[] or the GetChildRows of the DataRow object.

DataRowVersion informuje o tom, jaká verze DataRow existuje.The DataRowVersion informs you what version of a DataRow exists. Verze se mění v následujících případech:Versions change under the following circumstances:

  • Po volání metody BeginEdit DataRow objektu, pokud změníte hodnotu, budou hodnoty Current a Proposed k dispozici.After calling the DataRow object's BeginEdit method, if you change the value, the Current and Proposed values become available.

  • Po volání metody CancelEdit objektu DataRow se hodnota Proposed odstraní.After calling the DataRow object's CancelEdit method, the Proposed value is deleted.

  • Po volání metody EndEdit objektu DataRow se navrhovaná hodnota zobrazí jako hodnota Current.After calling the DataRow object's EndEdit method, the Proposed value becomes the Current value.

  • Po volání metody AcceptChanges objektu DataRow se hodnota Original bude shodovat s hodnotou Current.After calling the DataRow object's AcceptChanges method, the Original value becomes identical to the Current value.

  • Po volání metody AcceptChanges objektu DataTable se hodnota Original bude shodovat s hodnotou Current.After calling the DataTable object's AcceptChanges method, the Original value becomes identical to the Current value.

  • Po volání metody RejectChanges objektu DataRow je hodnota Proposed zahozena a verze se bude Current.After calling the DataRow object's RejectChanges method, the Proposed value is discarded, and the version becomes Current.

Applies to

See also