对 CreateParams 有效使用按位运算符，是不良行为吗？

Question

我正在为 ProgressBar 控件编写一个包装器（不是真正的包装器，而是正确实现 Vista 功能）。这是我的代码：

    /// <summary>
    /// Encapsulates the information needed when creating a control
    /// </summary>
    protected override CreateParams CreateParams {
        [SecurityPermission(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.UnmanagedCode)]
        get {
            CreateParams cp = base.CreateParams;
            if (SmoothReverse) {
                // Add using bitwise OR
                cp.Style = cp.Style | PBS_SMOOTHREVERSE;
            }
            else {
                // Remove using bitwise XOR
                cp.Style = cp.Style ^ PBS_SMOOTHREVERSE;
            }
            if (Vertical) {
                // Add using bitwise OR
                cp.Style = cp.Style | PBS_VERTICAL;
            }
            else {
                // Remove using bitwise XOR
                cp.Style = cp.Style ^ PBS_VERTICAL;
            }
            return cp;
        }
    }

    private bool m_SmoothReverse = false;
    /// <summary>
    /// Gets or sets a System.Boolean value indicating whether the SmoothReverse style is used
    /// </summary>
    [Category("Behavior")]
    [DefaultValue(false)]
    [Description("Gets or sets a System.Boolean value indicating whether the SmoothReverse style is used")]
    public bool SmoothReverse {
        get {
            return m_SmoothReverse;
        }
        set {
            m_SmoothReverse = value;
        }
    }

    private bool m_Vertical = false;
    /// <summary>
    /// Gets or sets a System.Boolean value indicating whether the progress bar will be rendered vertically
    /// </summary>
    [Category("Behavior")]
    [DefaultValue(false)]
    [Description("Gets or sets a System.Boolean value indicating whether the progress bar will be rendered vertically")]
    public bool Vertical {
        get {
            return m_Vertical;
        }
        set {
            m_Vertical = value;
        }
    }

但问题是，当您将控件放在表单上时，它会以垂直形式开始，并带有 PBS_SMOOTH。所以我的问题是，在使用按位运算在 CreateParams.Style 上设置值之前，我应该做哪些额外的检查，或者我的按位运算（或事实上我的代码）是否正确？

感谢 Jon Skeet 的更新 能够完全修复此问题并正常工作，并通过应用 UpdateStyles() 来强制新样式根据属性中的需要 apply()，该控件现在按预期工作并经过改进:)

    /// <summary>
    /// Encapsulates the information needed when creating a control
    /// </summary>
    protected override CreateParams CreateParams {
        [SecurityPermission(SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.UnmanagedCode)]
        get {
            CreateParams cp = base.CreateParams;
            if (SmoothReverse) {
                cp.Style |= PBS_SMOOTHREVERSE;
            }
            else {
                cp.Style &= ~PBS_SMOOTHREVERSE;
            }
            if (Vertical) {
                cp.Style |= PBS_VERTICAL;
            }
            else {
                cp.Style &= ~PBS_VERTICAL;
            }
            return cp;
        }
    }

    private bool m_SmoothReverse = false;
    /// <summary>
    /// Gets or sets a System.Boolean value indicating whether the SmoothReverse style is used
    /// </summary>
    [Category("Behavior")]
    [DefaultValue(false)]
    [Description("Gets or sets a System.Boolean value indicating whether the SmoothReverse style is used")]
    public bool SmoothReverse {
        get {
            return m_SmoothReverse;
        }
        set {
            m_SmoothReverse = value;
            UpdateStyles();
        }
    }

    private bool m_Vertical = false;
    /// <summary>
    /// Gets or sets a System.Boolean value indicating whether the progress bar will be rendered vertically
    /// </summary>
    [Category("Behavior")]
    [DefaultValue(false)]
    [Description("Gets or sets a System.Boolean value indicating whether the progress bar will be rendered vertically")]
    public bool Vertical {
        get {
            return m_Vertical;
        }
        set {
            m_Vertical = value;
            UpdateStyles();
        }
    }

Answer 1

| 操作是正确的（尽管我会使用 |=），而 ^ 则不然。

这：

cp.Style = cp.Style ^ PBS_SMOOTHREVERSE;

只会反转已经存在的内容。你想要的：

cp.Style &= ~PBS_SMOOTHREVERSE;

这就是说，“用一个掩码来掩码该值，该掩码设置了除了 PBS_SMOOTHREVERSE 之外的所有位”。