Unfortunately, this is not imporssible, as Group control does not support overflow style child management. You have two options (maybe more):
- Create your custom group box and implement the "row overflow" logic yourself;
- You might embed a child TableLayoutPanel or ListBox in your group box, and add child items there;
for the TableLayoutPanel option, you might try below snippet to see if it matches your requriment:
TableLayoutPanel Table = new TableLayoutPanel();
Table.AutoSize = true;
Table.RowCount = 4;
Table.AutoSizeMode = System.Windows.Forms.AutoSizeMode.GrowAndShrink;
Table.GrowStyle = System.Windows.Forms.TableLayoutPanelGrowStyle.AddCols;
this.Controls.Add(Table);
for the listbox, you can try this RadioListBox, and also set:
listBox1.MultiColumn = true;
And also you need adjust the listbox height so that exactly 4 rows are there.
If WPF is an option, this will be trivial as you can do this with XAML, and implementation your own ItemTemplate is just a breeze.