net9.0-windows10.0.22621 
namespace System.Windows.Forms
{
    [DesignerSerializer("System.Windows.Forms.Design.ToolStripMenuItemCodeDomSerializer, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a", "System.ComponentModel.Design.Serialization.CodeDomSerializer, System.Design, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a")]
    [ToolStripItemDesignerAvailability(ToolStripItemDesignerAvailability.MenuStrip | ToolStripItemDesignerAvailability.ContextMenuStrip)]
    public class ToolStripMenuItem : ToolStripDropDownItem
    {
        public event EventHandler? CheckStateChanged;
    }
}
.NET
5.06.07.08.09.0
.NET Core
3.03.1
.NET Framework
2.03.03.54.04.54.5.14.5.24.64.6.14.6.24.74.7.14.7.24.84.8.1
Information specific to net9.0
Platforms This API is only available when you target a specific platform:
Windows
7.08.010.0.1776310.0.1836210.0.1904110.0.2034810.0.2200010.0.22621
Information specific to net9.0-windows10.0.22621
Assembly

System.Windows.Forms , Version=9.0.0.0, PublicKeyToken=b77a5c561934e089

Referencing

Your project needs to set <UseWindowsForms>True</UseWindowsForms>.

Platform Restrictions

The event adder is only supported on the following platforms:

  • Windows >= 6.1

The event remover is only supported on the following platforms:

  • Windows >= 6.1
  • Built-in API
  • Package-provided API