我做了一個自定義，TextBox這樣我就可以讓它有邊框，這很好用......問題是我想設置PasswordChar為*，但不起作用這是我的代碼：public  class TextBoxEx : TextBox{    // The TextBox    private TextBox textBox = new TextBox();    // Border color of the textbox    private Color borderColor = Color.Gray;    // Ctor    public TextBoxEx()    {        this.PasswordChar ='*';        this.Paint += new PaintEventHandler(TextBoxEx_Paint);        this.Resize += new EventHandler(TextBoxEx_Resize);        textBox.Multiline = true;        textBox.BorderStyle = BorderStyle.None;        this.Controls.Add(textBox);        this.UseSystemPasswordChar = true;        InvalidateSize();    }    // Exposed properties of the textbox    public override string Text    {        get { return textBox.Text; }        set { textBox.Text = value; }    }    // ... Expose other properties you need...    // The border color property    public Color BorderColor    {        get { return borderColor; }        set { borderColor = value; Invalidate(); }    }    // Expose the Click event for the texbox    public event EventHandler TextBoxClick    {        add { textBox.Click += value; }        remove { textBox.Click -= value; }    }    // ... Expose other events you need...    private void TextBoxEx_Resize(object sender, EventArgs e)    {        InvalidateSize();    }    private void TextBoxEx_Paint(object sender, PaintEventArgs e)    {        ControlPaint.DrawBorder(e.Graphics, this.ClientRectangle, borderColor, ButtonBorderStyle.Solid);    }    private void InvalidateSize()    {        textBox.Size = new Size(this.Width - 2, this.Height - 2);        textBox.Location = new Point(1, 1);    }}通常，當我嘗試默認設置自定義控件的屬性時，它不起作用，例如，如果我設置this.ReadOnly=true;這也行不通。所以問題不在于PasswordChar它本身。有人知道解決方案嗎？