public void RefreshMementoMenus()
{
// Should update undo / redo menus in form's menu strip
try
{
IMForm child = (IMForm)ActiveMdiChild;
MementoManager manager = child.GetMementoManager();
if (manager.hasUndo())
{
undoMenuItem.Enabled = true;
undoMenuItem.Text = "Undo " + manager.GetUndoDesc();
}
else
{
undoMenuItem.Enabled = false;
undoMenuItem.Text = "Undo";
}
if (manager.hasRedo())
{
redoMenuItem.Enabled = true;
redoMenuItem.Text = "Redo " + manager.GetRedoDesc();
}
else
{
redoMenuItem.Enabled = false;
redoMenuItem.Text = "Redo";
}
}
catch (NullReferenceException)
{
// No active child yet; menus should be disabled
undoMenuItem.Enabled = false;
undoMenuItem.Text = "Undo";
redoMenuItem.Enabled = false;
redoMenuItem.Text = "Redo";
}
catch (InvalidCastException)
{
// Active Mdi Child is not an IMForm; disable menus
undoMenuItem.Enabled = false;
undoMenuItem.Text = "Undo";
redoMenuItem.Enabled = false;
redoMenuItem.Text = "Redo";
}
}
private void redoMenuItem_Click(object sender, EventArgs e)
{
try
{
IMForm child = (IMForm)ActiveMdiChild;
MementoManager manager = child.GetMementoManager();
manager.Redo();
child.RefreshValues();
}
catch (NullReferenceException)
{
// There is no child form yet
}
catch (InvalidCastException)
{
// Mdi child is not an IMForm
}
}