尝试这些链接 -

的A组合框与CheckedListBox作为下拉 [ ^ ]

复选框组合框扩展ComboBox类及其项 [ ^ ]

一个的OwnerDraw的组合框的CheckBox在下拉列表中 [ ^ ]

How to add checkbox to combobox in Windows Forms c#

Try these links -
A ComboBox with a CheckedListBox as a Dropdown[^]
CheckBox ComboBox Extending the ComboBox Class and Its Items[^]
An OwnerDraw ComboBox with CheckBoxes in the Drop-Down[^]