自学教程：C++ GetSelectionRange函数代码示例

bool SjColumnMixer::GetSelectionAnchor(long& colIndex__, long& rowIndex__){	SjCol* currCol;	// verify stored anchor	if( m_selAnchorColIndex != -1 )	{		currCol = GetMaskedCol(m_selAnchorColIndex);		if( currCol == NULL )		{			m_selAnchorColIndex = -1; // recalculate anchor - this is no error!		}		else		{			if(  m_selAnchorRowIndex<0 || m_selAnchorRowIndex>=currCol->m_rowCount			        || !currCol->m_rows[m_selAnchorRowIndex]->IsSelected() )			{				m_selAnchorColIndex = -1; // recalculate anchor - this is no error!			}			delete currCol;		}	}	// recalculate anchor if needed	if( m_selAnchorColIndex == -1 || GetSelectedUrlCount() == 1 )	{		GetSelectionRange(m_selAnchorColIndex, m_selAnchorRowIndex);	}	// done	colIndex__ = m_selAnchorColIndex;	rowIndex__ = m_selAnchorRowIndex;	return m_selAnchorColIndex!=-1;}

voidHTMLTextAreaElement::SetSelectionEnd(uint32_t aSelectionEnd, ErrorResult& aError){  if (mState.IsSelectionCached()) {    mState.GetSelectionProperties().mEnd = aSelectionEnd;    return;  }  nsAutoString direction;  nsresult rv = GetSelectionDirection(direction);  if (NS_FAILED(rv)) {    aError.Throw(rv);    return;  }  int32_t start, end;  rv = GetSelectionRange(&start, &end);  if (NS_FAILED(rv)) {    aError.Throw(rv);    return;  }  end = aSelectionEnd;  if (start > end) {    start = end;  }  rv = SetSelectionRange(start, end, direction);  if (NS_FAILED(rv)) {    aError.Throw(rv);  }}

voidHTMLTextAreaElement::SetSelectionEnd(const Nullable<uint32_t>& aSelectionEnd,                                     ErrorResult& aError){  int32_t selEnd = 0;  if (!aSelectionEnd.IsNull()) {    selEnd = aSelectionEnd.Value();  }  if (mState.IsSelectionCached()) {    mState.GetSelectionProperties().SetEnd(selEnd);    return;  }  nsAutoString direction;  nsresult rv = GetSelectionDirection(direction);  if (NS_FAILED(rv)) {    aError.Throw(rv);    return;  }  int32_t start, end;  rv = GetSelectionRange(&start, &end);  if (NS_FAILED(rv)) {    aError.Throw(rv);    return;  }  end = selEnd;  if (start > end) {    start = end;  }  rv = SetSelectionRange(start, end, direction);  if (NS_FAILED(rv)) {    aError.Throw(rv);  }}

NS_IMETHODIMPnsHTMLTextAreaElement::GetSelectionEnd(PRInt32 *aSelectionEnd){  NS_ENSURE_ARG_POINTER(aSelectionEnd);    PRInt32 selStart;  return GetSelectionRange(&selStart, aSelectionEnd);}

uint32_tHTMLTextAreaElement::GetSelectionEnd(ErrorResult& aError){  int32_t selStart, selEnd;  nsresult rv = GetSelectionRange(&selStart, &selEnd);  if (NS_FAILED(rv) && mState.IsSelectionCached()) {    return mState.GetSelectionProperties().mEnd;  }  if (NS_FAILED(rv)) {    aError.Throw(rv);  }  return selEnd;}

Nullable<uint32_t>HTMLTextAreaElement::GetSelectionStart(ErrorResult& aError){  int32_t selStart, selEnd;  nsresult rv = GetSelectionRange(&selStart, &selEnd);  if (NS_FAILED(rv) && mState.IsSelectionCached()) {    return Nullable<uint32_t>(mState.GetSelectionProperties().GetStart());  }  if (NS_FAILED(rv)) {    aError.Throw(rv);  }  return Nullable<uint32_t>(selStart);}

voidHTMLTextAreaElement::SetSelectionDirection(const nsAString& aDirection, ErrorResult& aError){  if (mState.IsSelectionCached()) {    nsITextControlFrame::SelectionDirection dir = nsITextControlFrame::eNone;    if (aDirection.EqualsLiteral("forward")) {      dir = nsITextControlFrame::eForward;    } else if (aDirection.EqualsLiteral("backward")) {      dir = nsITextControlFrame::eBackward;    }    mState.GetSelectionProperties().mDirection = dir;    return;  }  int32_t start, end;  nsresult rv = GetSelectionRange(&start, &end);  if (NS_SUCCEEDED(rv)) {    rv = SetSelectionRange(start, end, aDirection);  }  if (NS_FAILED(rv)) {    aError.Throw(rv);  }}

voidHTMLTextAreaElement::SetRangeText(const nsAString& aReplacement,                                  uint32_t aStart, uint32_t aEnd,                                  const SelectionMode& aSelectMode,                                  ErrorResult& aRv, int32_t aSelectionStart,                                  int32_t aSelectionEnd){  if (aStart > aEnd) {    aRv.Throw(NS_ERROR_DOM_INDEX_SIZE_ERR);    return;  }  nsAutoString value;  GetValueInternal(value, false);  uint32_t inputValueLength = value.Length();  if (aStart > inputValueLength) {    aStart = inputValueLength;  }  if (aEnd > inputValueLength) {    aEnd = inputValueLength;  }  if (aSelectionStart == -1 && aSelectionEnd == -1) {    aRv = GetSelectionRange(&aSelectionStart, &aSelectionEnd);    if (aRv.Failed()) {      if (mState.IsSelectionCached()) {        aSelectionStart = mState.GetSelectionProperties().mStart;        aSelectionEnd = mState.GetSelectionProperties().mEnd;        aRv = NS_OK;      }    }  }  if (aStart <= aEnd) {    value.Replace(aStart, aEnd - aStart, aReplacement);    SetValueInternal(value, false);  }  uint32_t newEnd = aStart + aReplacement.Length();  int32_t delta =  aReplacement.Length() - (aEnd - aStart);  switch (aSelectMode) {    case mozilla::dom::SelectionMode::Select:    {      aSelectionStart = aStart;      aSelectionEnd = newEnd;    }    break;    case mozilla::dom::SelectionMode::Start:    {      aSelectionStart = aSelectionEnd = aStart;    }    break;    case mozilla::dom::SelectionMode::End:    {      aSelectionStart = aSelectionEnd = newEnd;    }    break;    case mozilla::dom::SelectionMode::Preserve:    {      if ((uint32_t)aSelectionStart > aEnd) {        aSelectionStart += delta;      } else if ((uint32_t)aSelectionStart > aStart) {        aSelectionStart = aStart;      }      if ((uint32_t)aSelectionEnd > aEnd) {        aSelectionEnd += delta;      } else if ((uint32_t)aSelectionEnd > aStart) {        aSelectionEnd = newEnd;      }    }    break;  }  Optional<nsAString> direction;  SetSelectionRange(aSelectionStart, aSelectionEnd, direction, aRv);}

bool SjColumnMixer::SelectShifted(int keyPressed/*-1=up, +1=down*/, long& retScopeColIndex, long& retScopeRowIndex){	long    firstSelColIndex, firstSelRowIndex,	        lastSelColIndex, lastSelRowIndex;	bool    prevNextOk;	// get selection anchor and the first/last selected row	if( !GetSelectionAnchor(firstSelColIndex/*dummy*/, firstSelRowIndex/*dummy*/)	        || !GetSelectionRange(firstSelColIndex, firstSelRowIndex, &lastSelColIndex, &lastSelRowIndex) )	{		return FALSE; // no anchor, the caller should preform a "simple" selection	}	// calculate the new selection...	if( firstSelColIndex == lastSelColIndex && firstSelRowIndex == lastSelRowIndex )	{		if( keyPressed == -1 )		{			// ...initial selection from anchor to top			prevNextOk = PrevNextRow(firstSelColIndex, firstSelRowIndex, -1);			retScopeColIndex = firstSelColIndex;			retScopeRowIndex = firstSelRowIndex;		}		else		{			// ...initial selection from anchor to bottom			prevNextOk = PrevNextRow(lastSelColIndex, lastSelRowIndex, +1);			retScopeColIndex = lastSelColIndex;			retScopeRowIndex = lastSelRowIndex;		}	}	else if(  firstSelColIndex < m_selAnchorColIndex	          || (firstSelColIndex == m_selAnchorColIndex && firstSelRowIndex < m_selAnchorRowIndex) )	{		// ...selected stuff above the anchor...		prevNextOk = PrevNextRow(firstSelColIndex, firstSelRowIndex, keyPressed);		retScopeColIndex = firstSelColIndex;		retScopeRowIndex = firstSelRowIndex;	}	else	{		// ...select stuff below the anchor...		prevNextOk = PrevNextRow(lastSelColIndex, lastSelRowIndex, keyPressed);		retScopeColIndex = lastSelColIndex;		retScopeRowIndex = lastSelRowIndex;	}	if( prevNextOk )	{		// set the new selection		SetSelectionRange(firstSelColIndex, firstSelRowIndex, lastSelColIndex, lastSelRowIndex, TRUE);		// make sure, the anchor is always selected		SjCol* col = GetMaskedCol(m_selAnchorColIndex);		if( col )		{			if( m_selAnchorRowIndex >= 0 && m_selAnchorRowIndex < col->m_rowCount )			{				col->m_rows[m_selAnchorRowIndex]->Select(TRUE);			}			delete col;		}	}	return TRUE;}

Nullable<uint32_t> HTMLTextAreaElement::GetSelectionEnd(ErrorResult& aError) {  uint32_t selStart, selEnd;  GetSelectionRange(&selStart, &selEnd, aError);  return Nullable<uint32_t>(selEnd);}