如何检测滚动条是否位于富文本框的末尾(vb.net) [英] How to detect if a scrollbar is or is not at the end of a richtextbox (vb.net)

问题描述

我的问题是:如何检测滚动条是否位于富文本框的末尾?

my question is as is:How to detect if a scrollbar is at or not at the end of a richtextbox?

当我说最后我的意思是完全滚动到底部，而不是其他任何地方.

edit: when I say at the end I mean completely scrolled to the bottom, not anywhere else.

推荐答案

查看 GetScrollRange 和 GetScrollPos API...

Check out the GetScrollRange and 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

注意事项:

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

To determine if the scrollbar is visible, call GetWindowLong and check for WS_VSCROLL

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

To determine the max value the slider can get to, call GetScrollInfo; I think the maximum value is

scrollMax - largeChange + 1

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