我需要创建WinForms项目下的组件。NET库版本6.0。但是，当我创建项目和ControlLibrary时，Visual Studio窗体设计器并不使用ControlLibrary中的ControlDesigners，即使我正确地将设计器绑定到组件。

[Designer(typeof(MyControlDesigner))]
  [ToolboxItem(true)]
  public class MyControl : Control 
  {

    protected override void OnPaint(PaintEventArgs e)
    {
      e.Graphics.FillRectangle(SystemBrushes.Info, new Rectangle(0, 0, Width, Height));
      e.Graphics.DrawString("MyControl", Font, SystemBrushes.InfoText, new PointF(0, 0));
    }
  }

我已经创建了一些ActionList，但它们在设计时没有显示在组件中。

namespace WinFormsControlLibrary1
{
  internal class MyControlDesigner : ControlDesigner
  {
    private DesignerActionListCollection actionLists;

    public override DesignerActionListCollection ActionLists
    {
      get
      {
        if (actionLists == null)
        {
          actionLists = new DesignerActionListCollection();
          actionLists.Add(new DataAxisGridActionList(Component));
          actionLists.AddRange(base.ActionLists);
        }
        return actionLists;
      }
    }
  }

  public class DataAxisGridActionList : DesignerActionList
  {

    public DataAxisGridActionList(IComponent component) : base(component)
    {
    }

    public override DesignerActionItemCollection GetSortedActionItems()
    {
      DesignerActionItemCollection items = new DesignerActionItemCollection();
      items.Add(new DesignerActionMethodItem(this, "Action1", " Action 1", true));
      items.Add(new DesignerActionMethodItem(this, "Action2", "Action 2", true));
      return items;
    }

    public void Action1()
    {
      MessageBox.Show("Action 1");
    }

    public void Action2()
    {
      MessageBox.Show("Action 2");
    }
  }

}

为了测试，我在.NET Framework 4.7.2下创建了一个类似的项目和库，设计器在那里正常工作。

我还附上一个链接到演示项目。
https://github.com/dmitrybv/WinForms-Net5-Designers
https://github.com/dmitrybv/WinForms-Net-Framework-4.7.2-Designers