如何强制DropDownList样式ComboBox仅在用户单击下拉按钮时打开？

In C# .NET 2.0, I have a WinForms ComboBox with ComboBoxStyle DropDownList. However, the drop down appears whenever the user clicks anywhere on the combo box. Instead, I'd like to have it only open when the user explicitly clicks on the drop down button. When the user clicks on the rest of the combo box, I'd like to just assign it the keyboard focus so he or she can use some keyboard commands on the selected item. What's the best way to do this?In C# .NET 2.0, I have a WinForms ComboBox with