PropertyGrid: DropDown Editor

You may want to add a dropdown to your property grid. If you do then the below code is what you will need to create the editor.

Build the DropDown Editor

 public class DropDownEditor : System.Drawing.Design.UITypeEditor
{
      private IWindowsFormsEditorService es = null;
      public override UITypeEditorEditStyle GetEditStyle(System.ComponentModel.ITypeDescriptorContext context)
      {
            return UITypeEditorEditStyle.DropDown;
      }

      public override object EditValue(ITypeDescriptorContext context, IServiceProvider provider, object value)
      {
            if (provider != null)
            {
                  // This service is in charge of popping our ListBox.
                  es = ((IWindowsFormsEditorService)provider.GetService(typeof(IWindowsFormsEditorService)));

                  if (es != null && value is DropDownList)
                  {
                        dynamic property = (DropDownList)value;
                        var list = new ListBox();
                        list.Click += ListBox_Click;

                        if (property.Values != null)
                        {
                              foreach (object item in property.Values)
                              {
                                    var propertyInfo = item.GetType().GetProperty(property.DisplayMember);
                                    list.Items.Add(propertyInfo.GetValue(item, null));
                              }
                        }
                        // Drop the list control.
                        es.DropDownControl(list);

                        if (list.SelectedItem != null && list.SelectedIndices.Count == 1)
                        {
                              property.SelectedItem = list.SelectedItem;
                              value = property;
                        }
                  }
            }

            return value;
      }

      void ListBox_Click(object sender, EventArgs e)
      {
            if (es != null)
            {
                  es.CloseDropDown();
            }
      }
}