如何将列表中的项目添加到GenericMenu (编辑器窗口)，并且只能选择一个

GenericMenu menu = new GenericMenu();

foreach (string project in projectList)
{
    menu.AddItem(new GUIContent(project), false, OnMenuItemSelected, project);
}

Rect menuRect = new Rect(Event.current.mousePosition.x, Event.current.mousePosition.y, 0, 0);

menu.DropDown(menuRect);

using UnityEditor;
using UnityEngine;
using System.Collections.Generic;

public class MyEditorWindow : EditorWindow
{
    private List<string> projectList = new List<string>() { "Project 1", "Project 2", "Project 3" };

    [MenuItem("Window/My Editor Window")]
    public static void ShowWindow()
    {
        EditorWindow.GetWindow(typeof(MyEditorWindow));
    }

    private void OnGUI()
    {
        if (GUILayout.Button("Show Menu"))
        {
            ShowMenu();
        }
    }

    private void ShowMenu()
    {
        GenericMenu menu = new GenericMenu();

        foreach (string project in projectList)
        {
            menu.AddItem(new GUIContent(project), false, OnMenuItemSelected, project);
        }

        Rect menuRect = new Rect(Event.current.mousePosition.x, Event.current.mousePosition.y, 0, 0);
        menu.DropDown(menuRect);
    }

    private void OnMenuItemSelected(object project)
    {
        string selectedProject = (string)project;
        Debug.Log("Selected project: " + selectedProject);
    }
}