private void spalteEinfügenToolStripMenuItem_Click(object sender, EventArgs e) { if (sender is ToolStripItem menuItem) { if (menuItem.Owner is ContextMenuStrip owner) { if (owner.SourceControl is DataGridView dataGrid) { if (dataGrid.DataSource is DataTable dataTable) { var dialog = new AddColumnDialog(); if (dialog.ShowDialog() == DialogResult.OK) { _controller.AddColumn(dataTable, dialog.ColumnViewModel); } } } } } }