DataGridView.SelectedColumns Proprietà

Definizione

Spazio dei nomi:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

Ottiene la raccolta di colonne selezionate dall'utente.

public:
 property System::Windows::Forms::DataGridViewSelectedColumnCollection ^ SelectedColumns { System::Windows::Forms::DataGridViewSelectedColumnCollection ^ get(); };

[System.ComponentModel.Browsable(false)]
public System.Windows.Forms.DataGridViewSelectedColumnCollection SelectedColumns { get; }

[<System.ComponentModel.Browsable(false)>]
member this.SelectedColumns : System.Windows.Forms.DataGridViewSelectedColumnCollection

Public ReadOnly Property SelectedColumns As DataGridViewSelectedColumnCollection

Valore della proprietà

DataGridViewSelectedColumnCollection

Oggetto DataGridViewSelectedColumnCollection che rappresenta le colonne selezionate dall'utente.

Attributi

BrowsableAttribute

Esempio

Nell'esempio di codice seguente viene illustrato come usare la SelectedColumns proprietà per ottenere la colonna selezionata in un ordinamento programmatico. In questo esempio questa proprietà viene usata nel Sort metodo per determinare la direzione dell'ordinamento.

private void sortButton_Click(object sender, System.EventArgs e)
{
    // Check which column is selected, otherwise set NewColumn to null.
    DataGridViewColumn newColumn =
        dataGridView1.Columns.GetColumnCount(
        DataGridViewElementStates.Selected) == 1 ?
        dataGridView1.SelectedColumns[0] : null;

    DataGridViewColumn oldColumn = dataGridView1.SortedColumn;
    ListSortDirection direction;

    // If oldColumn is null, then the DataGridView is not currently sorted.
    if (oldColumn != null)
    {
        // Sort the same column again, reversing the SortOrder.
        if (oldColumn == newColumn &&
            dataGridView1.SortOrder == SortOrder.Ascending)
        {
            direction = ListSortDirection.Descending;
        }
        else
        {
            // Sort a new column and remove the old SortGlyph.
            direction = ListSortDirection.Ascending;
            oldColumn.HeaderCell.SortGlyphDirection = SortOrder.None;
        }
    }
    else
    {
        direction = ListSortDirection.Ascending;
    }

    // If no column has been selected, display an error dialog  box.
    if (newColumn == null)
    {
        MessageBox.Show("Select a single column and try again.",
            "Error: Invalid Selection", MessageBoxButtons.OK,
            MessageBoxIcon.Error);
    }
    else
    {
        dataGridView1.Sort(newColumn, direction);
        newColumn.HeaderCell.SortGlyphDirection =
            direction == ListSortDirection.Ascending ?
            SortOrder.Ascending : SortOrder.Descending;
    }
}

Private Sub SortButton_Click(ByVal sender As Object, _
    ByVal e As EventArgs) Handles sortButton.Click

    ' Check which column is selected, otherwise set NewColumn to Nothing.
    Dim newColumn As DataGridViewColumn
    If dataGridView1.Columns.GetColumnCount(DataGridViewElementStates _
        .Selected) = 1 Then
        newColumn = dataGridView1.SelectedColumns(0)
    Else
        newColumn = Nothing
    End If

    Dim oldColumn As DataGridViewColumn = dataGridView1.SortedColumn
    Dim direction As ListSortDirection

    ' If oldColumn is null, then the DataGridView is not currently sorted.
    If oldColumn IsNot Nothing Then

        ' Sort the same column again, reversing the SortOrder.
        If oldColumn Is newColumn AndAlso dataGridView1.SortOrder = _
            SortOrder.Ascending Then
            direction = ListSortDirection.Descending
        Else

            ' Sort a new column and remove the old SortGlyph.
            direction = ListSortDirection.Ascending
            oldColumn.HeaderCell.SortGlyphDirection = SortOrder.None
        End If
    Else
        direction = ListSortDirection.Ascending
    End If


    ' If no column has been selected, display an error dialog  box.
    If newColumn Is Nothing Then
        MessageBox.Show("Select a single column and try again.", _
            "Error: Invalid Selection", MessageBoxButtons.OK, _
            MessageBoxIcon.Error)
    Else
        dataGridView1.Sort(newColumn, direction)
        If direction = ListSortDirection.Ascending Then
            newColumn.HeaderCell.SortGlyphDirection = SortOrder.Ascending
        Else
            newColumn.HeaderCell.SortGlyphDirection = SortOrder.Descending
        End If
    End If

End Sub

Commenti

La SelectionMode proprietà deve essere impostata su DataGridViewSelectionMode.FullColumnSelect o DataGridViewSelectionMode.ColumnHeaderSelect per la SelectedColumns proprietà da popolare con colonne selezionate.

Questa proprietà contiene uno snapshot di sola lettura della selezione al momento in cui viene fatto riferimento. Se si tiene premuta una copia di questa raccolta, può essere diversa dallo stato effettivo, successivo DataGridView in cui l'utente potrebbe aver modificato la selezione. Pertanto, non è consigliabile operare su una copia della raccolta.

Vedi anche

• Controllo DataGridView (Windows Form)