您可以使用以下方法,而不是使用 SendMessage 并将您的 DLL 标记为不安全GetScrollPos
and SetScrollPos
user32.dll 中的函数。
我已将代码包装到您的 MyTreeView 类中,因此它得到了很好的封装。
您只需要致电AddLinkedTreeView
像这样的方法:
treeView1.AddLinkedTreeView(treeView2);
这是 MyTreeView 类的源代码。
public partial class MyTreeView : TreeView
{
public MyTreeView() : base()
{
}
private List<MyTreeView> linkedTreeViews = new List<MyTreeView>();
/// <summary>
/// Links the specified tree view to this tree view. Whenever either treeview
/// scrolls, the other will scroll too.
/// </summary>
/// <param name="treeView">The TreeView to link.</param>
public void AddLinkedTreeView(MyTreeView treeView)
{
if (treeView == this)
throw new ArgumentException("Cannot link a TreeView to itself!", "treeView");
if (!linkedTreeViews.Contains(treeView))
{
//add the treeview to our list of linked treeviews
linkedTreeViews.Add(treeView);
//add this to the treeview's list of linked treeviews
treeView.AddLinkedTreeView(this);
//make sure the TreeView is linked to all of the other TreeViews that this TreeView is linked to
for (int i = 0; i < linkedTreeViews.Count; i++)
{
//get the linked treeview
var linkedTreeView = linkedTreeViews[i];
//link the treeviews together
if (linkedTreeView != treeView)
linkedTreeView.AddLinkedTreeView(treeView);
}
}
}
/// <summary>
/// Sets the destination's scroll positions to that of the source.
/// </summary>
/// <param name="source">The source of the scroll positions.</param>
/// <param name="dest">The destinations to set the scroll positions for.</param>
private void SetScrollPositions(MyTreeView source, MyTreeView dest)
{
//get the scroll positions of the source
int horizontal = User32.GetScrollPos(source.Handle, Orientation.Horizontal);
int vertical = User32.GetScrollPos(source.Handle, Orientation.Vertical);
//set the scroll positions of the destination
User32.SetScrollPos(dest.Handle, Orientation.Horizontal, horizontal, true);
User32.SetScrollPos(dest.Handle, Orientation.Vertical, vertical, true);
}
protected override void WndProc(ref Message m)
{
//process the message
base.WndProc(ref m);
//pass scroll messages onto any linked views
if (m.Msg == User32.WM_VSCROLL || m.Msg == User32.WM_MOUSEWHEEL)
{
foreach (var linkedTreeView in linkedTreeViews)
{
//set the scroll positions of the linked tree view
SetScrollPositions(this, linkedTreeView);
//copy the windows message
Message copy = new Message
{
HWnd = linkedTreeView.Handle,
LParam = m.LParam,
Msg = m.Msg,
Result = m.Result,
WParam = m.WParam
};
//pass the message onto the linked tree view
linkedTreeView.RecieveWndProc(ref copy);
}
}
}
/// <summary>
/// Recieves a WndProc message without passing it onto any linked treeviews. This is useful to avoid infinite loops.
/// </summary>
/// <param name="m">The windows message.</param>
private void RecieveWndProc(ref Message m)
{
base.WndProc(ref m);
}
/// <summary>
/// Imported functions from the User32.dll
/// </summary>
private class User32
{
public const int WM_VSCROLL = 0x115;
public const int WM_MOUSEWHEEL = 0x020A;
[DllImport("user32.dll", CharSet = CharSet.Auto)]
public static extern int GetScrollPos(IntPtr hWnd, System.Windows.Forms.Orientation nBar);
[DllImport("user32.dll")]
public static extern int SetScrollPos(IntPtr hWnd, System.Windows.Forms.Orientation nBar, int nPos, bool bRedraw);
}
}
Edit:按照 MinnesotaFat 的建议添加了 WM_MOUSEWHEEL 消息的转发。