How to: Expand and Collapse Master Rows

• Jun 07, 2019
• 3 minutes to read

This sample shows you a few members that allow expanding and collapsing master rows. Keyboard presses are processed to allow the CTRL+* shortcut to toggle the currently focused master row’s state. There are also two buttons - one allowing expansion of all master rows, and another that collapses details for all but the focused row.

The following members are used in this example:

Member	Description
GridControl.CollapseMasterRow	Collapses the detail section for the specified row.
GridControl.ExpandMasterRow	Expands the specified master row and, optionally, shows the specified Detail.
GridControl.IsMasterRowExpanded	Determines the specified master row’s expanded state and, optionally, the specified Detail’s visibility.
GridControl.SetMasterRowExpanded	Changes the expanded state for a specified master row and, optionally, shows a specified Detail.

Note

A complete sample project is available at https://github.com/DevExpress-Examples/expanding-and-collapsing-master-rows-e4044.

MainWindow.xaml.vb

Private Sub TableView_KeyDown(ByVal sender As Object, ByVal e As KeyEventArgs)
    Dim view As TableView = TryCast(sender, TableView)

    ' Avoid key processing when focus is within detail views
    ' or when a groupo row is focused
    If Not view.IsFocusedView OrElse view.FocusedRowHandle < 0 Then
        Return
    End If

    ' Process CTRL+* key combination
    If e.Key = Key.Multiply AndAlso ((Keyboard.Modifiers And ModifierKeys.Control) = ModifierKeys.Control) Then
        Dim finalExpandedState As Boolean = Not view.Grid.IsMasterRowExpanded(view.FocusedRowHandle)
        view.Grid.SetMasterRowExpanded(view.FocusedRowHandle, finalExpandedState)
        e.Handled = True
    End If
End Sub
Private Sub buttonExpandAll_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
    For i As Integer = 0 To gridControl1.VisibleRowCount - 1
        Dim rowHandle = gridControl1.GetRowHandleByVisibleIndex(i)
        gridControl1.ExpandMasterRow(rowHandle)
    Next i
End Sub
Private Sub buttonCollapseAllButThis_Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
    If tableView1.FocusedRowHandle >= 0 Then
        gridControl1.ExpandMasterRow(tableView1.FocusedRowHandle)
    End If
    For i As Integer = 0 To gridControl1.VisibleRowCount - 1
        Dim rowHandle As Integer = gridControl1.GetRowHandleByVisibleIndex(i)
        If rowHandle <> tableView1.FocusedRowHandle Then
            gridControl1.CollapseMasterRow(rowHandle)
        End If
    Next i
End Sub

MainWindow.xaml.cs

private void TableView_KeyDown(object sender, KeyEventArgs e)
{
    TableView view = sender as TableView;

    // Avoid key processing when focus is within detail views
    // or when a groupo row is focused
    if (!view.IsFocusedView || view.FocusedRowHandle < 0)
        return;

    // Process CTRL+* key combination
    if (e.Key == Key.Multiply && ((Keyboard.Modifiers & ModifierKeys.Control) == ModifierKeys.Control))
    {
        bool finalExpandedState = !view.Grid.IsMasterRowExpanded(view.FocusedRowHandle);
        view.Grid.SetMasterRowExpanded(view.FocusedRowHandle, finalExpandedState);
        e.Handled = true;
    }
}
private void buttonExpandAll_Click(object sender, RoutedEventArgs e)
{
    for (int i = 0; i < gridControl1.VisibleRowCount; i++)
    {
        var rowHandle = gridControl1.GetRowHandleByVisibleIndex(i);
        gridControl1.ExpandMasterRow(rowHandle);
    }
}
private void buttonCollapseAllButThis_Click(object sender, RoutedEventArgs e)
{
    if (tableView1.FocusedRowHandle >= 0)
        gridControl1.ExpandMasterRow(tableView1.FocusedRowHandle);
    for (int i = 0; i < gridControl1.VisibleRowCount; i++)
    {
        int rowHandle = gridControl1.GetRowHandleByVisibleIndex(i);
        if (rowHandle != tableView1.FocusedRowHandle)
            gridControl1.CollapseMasterRow(rowHandle);
    }
}