我想滚动一个RichTextBox,以便插入符号大致位于RichTextBox的中间。
像RichTextBox.ScrollToCaret()之类的东西,除了我不想把插入符号放在最顶端。
我看到Winforms: Screen Location of Caret Position,当然也看到了Win32函数SetCaretPos()。但我不确定如何将SetCaretPos所需的x,y转换为richtextbox中的行。
答案 0 :(得分:6)
如果富文本框位于_rtb中,则可以获得可见行数:
public int NumberOfVisibleLines
{
get
{
int topIndex = _rtb.GetCharIndexFromPosition(new System.Drawing.Point(1, 1));
int bottomIndex = _rtb.GetCharIndexFromPosition(new System.Drawing.Point(1, _rtb.Height - 1));
int topLine = _rtb.GetLineFromCharIndex(topIndex);
int bottomLine = _rtb.GetLineFromCharIndex(bottomIndex);
int n = bottomLine - topLine + 1;
return n;
}
}
然后,如果要将插入符号滚动到富文本框顶部的1/3处,请执行以下操作:
int startLine = _rtb.GetLineFromCharIndex(ix);
int numVisibleLines = NumberOfVisibleLines;
// only scroll if the line to scroll-to, is larger than the
// the number of lines that can be displayed at once.
if (startLine > numVisibleLines)
{
int cix = _rtb.GetFirstCharIndexFromLine(startLine - numVisibleLines/3 +1);
_rtb.Select(cix, cix+1);
_rtb.ScrollToCaret();
}