因此,可以在没有p / invoke的情况下拦截和转发消息到任何控件.虽然这很隐蔽.

/// <summary>
/// This class implements a filter for the Windows.Forms message pump allowing a
/// specific message to be forwarded to the Control specified in the constructor.
/// Adding and removing of the filter is done automatically.
/// </summary>
public class MessageForwarder : NativeWindow,IMessageFilter
{
    #region Fields

    private Control _Control;
    private Control _PrevIoUsParent;
    private HashSet<int> _Messages;
    private bool _IsMouSEOverControl;

    #endregion // Fields

    #region Constructors

    public MessageForwarder(Control control,int message)
        : this(control,new int[] { message }) { }

    public MessageForwarder(Control control,IEnumerable<int> messages)
    {
        _Control = control;
        AssignHandle(control.Handle);
        _Messages = new HashSet<int>(messages);
        _PrevIoUsParent = control.Parent;
        _IsMouSEOverControl = false;

        control.ParentChanged += new EventHandler(control_ParentChanged);
        control.MouseEnter += new EventHandler(control_MouseEnter);
        control.MouseLeave += new EventHandler(control_MouseLeave);
        control.Leave += new EventHandler(control_Leave);

        if (control.Parent != null)
            Application.AddMessageFilter(this);
    }

    #endregion // Constructors

    #region IMessageFilter members

    public bool PreFilterMessage(ref Message m)
    {
        if (_Messages.Contains(m.Msg) && _Control.CanFocus && !_Control.Focused
            && _IsMouSEOverControl)
        {
            m.HWnd = _Control.Handle;
            WndProc(ref m);
            return true;
        }

        return false;
    }

    #endregion // IMessageFilter

    #region Event handlers

    void control_ParentChanged(object sender,EventArgs e)
    {
        if (_Control.Parent == null)
            Application.RemoveMessageFilter(this);
        else
        {
            if (_PrevIoUsParent == null)
                Application.AddMessageFilter(this);
        }
        _PrevIoUsParent = _Control.Parent;
    }

    void control_MouseEnter(object sender,EventArgs e)
    {
        _IsMouSEOverControl = true;
    }

    void control_MouseLeave(object sender,EventArgs e)
    {
        _IsMouSEOverControl = false;
    }

    void control_Leave(object sender,EventArgs e)
    {
        _IsMouSEOverControl = false;
    }

    #endregion // Event handlers
}