.net - 如何检测滚动条是否位于 Richtextbox 的末尾 (vb.net)

Question

我的问题是:如何检测滚动条是否位于 Richtextbox 的末尾？

编辑:当我说最后时，我的意思是完全滚动到底部，而不是其他地方。

Answer 1

查看 GetScrollRange和 GetScrollPos API...

Private Const SBS_HORZ = 0
Private Const SBS_VERT = 1

<DllImport("user32.dll")> _
Public Function GetScrollRange(ByVal hWnd As IntPtr, ByVal nBar As Integer, _
                               ByRef lpMinPos As Integer, _
                               ByRef lpMaxPos As Integer) As Boolean
End Function

<DllImport("user32.dll")> _
Public Function GetScrollPos(ByVal hWnd As Integer, _
                             ByVal nBar As Integer) As Integer
End Function

// ...

Dim scrollMin as Integer = 0
Dim scrollMax as Integer = 0

If(GetScrollRange(rtb.Handle, SBS_VERT, scrollMin, scrollMax) Then
   Dim pos as Integer = GetScrollPos(rtb.Handle, SBS_VERT)

   // Detect if they're at the bottom
EndIf

注释:

要确定滚动条是否可见，请调用 GetWindowLong并检查 WS_VSCROLL

要确定 slider 可以达到的最大值，请调用 GetScrollInfo ;我认为最大值是

scrollMax - largeChange + 1