错误显示listview1由于安全级别而无法访问
窗体控件在由窗体设计器添加时默认不是public。您 * 可以 * 将其设置为public，但通常不建议编辑设计器控制的代码。（因为它可能会被设计器的进一步更改覆盖。）
在MainWindow上创建public * 方法 * 以执行此操作。例如：

public void AddListViewItem(ListViewItem lvi)
{
    this.listView1.Items.Add(lvi);
}

然后，您可以从其他窗体的代码中调用该公共方法：

mainWindow.AddListViewItem(lvi);

当你准备好将游戏提升到一个新的水平时，你的代码可以通过保持每个窗体的UI控件私有化并使用属性和方法来访问窗体之间的值来改进。问题是，我们真的不想让AddGame窗体访问主窗体的列表视图。这里有一个简化设计的方法，只需三个简单的步骤。

创建一个类来表示游戏（它将成为ListViewItem）

public class Game
{
    public string? Play0Name { get; set; }
    public string? Players { get; set; }
    public string? Sequence1 { get; set; }
    public string? Sequence2 { get; set; }
    public string? Winner { get; set; }
    public string? Comments { get; set; }
    public DateTime GameDate { get; set; }
}

添加游戏

当你显示“添加游戏”对话框时，它的目的是填充游戏类。一旦用户提供了足够的信息，新游戏是有效的，然后启用[确定]按钮。

public partial class AddGameForm : Form
{
    public AddGameForm()
    {
        InitializeComponent();
        StartPosition = FormStartPosition.Manual;
        buttonOK.Enabled = false; // Will be enabled when all the texboxes have values
        buttonOK.Click += (sender, e) =>DialogResult = DialogResult.OK;
        // Make an array of the textboxes.
        _textboxes = 
            Controls
            .Cast<Control>()
            .Where(_ => _ is TextBox)
            .Cast<TextBox>()
            .ToArray();
        foreach (var textbox in _textboxes) textbox.TextChanged += onAnyTextChanged;
    }
    // Determine if the game is valid by looking through all the textboxes.
    private void onAnyTextChanged(object? sender, EventArgs e)
    {
        buttonOK.Enabled = !_textboxes.Any(_=>string.IsNullOrWhiteSpace(_.Text));
    }
    private TextBox[] _textboxes;
    // If this dialog returns [OK] then the main form 
    // can retrieve the valid game using this method.
    public Game GetGame()
    {
        Game game = new Game
        {
            Play0Name = textBoxPlay0Name.Text,
            Players = textBoxPlayers.Text,
            Sequence1 = textBoxSequence1.Text,
            Sequence2 = textBoxSequence2.Text, 
            Winner = textBoxWinner.Text, 
            Comments = textBoxComments.Text, 
        };
        return game;
    }
    // Position the form relative to the main form when shown.
    protected override void OnVisibleChanged(EventArgs e)
    {
        base.OnVisibleChanged(e);
        if(Visible && Owner != null) 
        {
            Location = new Point(
                x: Owner.Location.X + Owner.Width + 10,
                y: Owner.Location.Y);
        }
    }
}

检索有效游戏

如果AddGameForm返回DialogResult.OK，则意味着它保存了一个有效的游戏表单，您可以检索该表单并将其分配给ListView。

public partial class MainForm : Form
{
    public MainForm()
    {
        InitializeComponent();
        buttonAddGame.Click += onClickAddGame;
    }        
    private void onClickAddGame(object? sender, EventArgs e)
    {
        using (AddGameForm addGame = new AddGameForm())
        {
            if (DialogResult.OK.Equals(addGame.ShowDialog(this)))
            {
                Game game = addGame.GetGame();
                // Use the info given via textboxes and add them to items/subitems
                ListViewItem lvi = new ListViewItem(game.Play0Name);
                lvi.SubItems.Add(game.Players);
                lvi.SubItems.Add(game.Sequence1);
                lvi.SubItems.Add(game.Sequence2);
                lvi.SubItems.Add(game.Comments);
                lvi.SubItems.Add(game.Winner);
                lvi.SubItems.Add(game.GameDate.ToShortDateString());

                // Add the items to the list view.
                listView1.Items.Add(lvi);
            }
        }
    }
}