void onInsertHyperlink()
{
//get the document fragment which the user has currently selected using mouse and/or cursor
IWindowSelection windowSelection = modelEdit.windowSelection;
//verify that there's only one selection
if (windowSelection.rangeCount != 1)
{
//this can happen when the user has selected several cell in a table,
//in which case each cell is a separate selection/range
MessageBox.Show("Can't insert a hyperlink when more than one range in the document is selected");
return;
}
using (IDomRange domRange = windowSelection.getRangeAt(0))
{
//verify that only one node is selected
if (!domRange.startContainer.isSameNode(domRange.endContainer))
{
//this can happen for example when the selection spans multiple paragraphs
MessageBox.Show("Can't insert a hyperlink when more than one node in the document is selected");
return;
}
IDomNode container = domRange.startContainer; //already just checked that this is the same as domRange.endContainer
//read existing values from the current selection
string url;
string visibleText;
IDomElement existingHyperlink;
switch (container.nodeType)
{
case DomNodeType.Text:
//selection is a text fragment
visibleText = container.nodeValue.Substring(domRange.startOffset, domRange.endOffset - domRange.startOffset);
IDomNode parentNode = container.parentNode;
if ((parentNode.nodeType == DomNodeType.Element) && (parentNode.nodeName == "a"))
{
//parent of this text node is a <a> element
existingHyperlink = parentNode as IDomElement;
url = existingHyperlink.getAttribute("href");
visibleText = container.nodeValue;
if ((existingHyperlink.childNodes.count != 1) || (existingHyperlink.childNodes.itemAt(0).nodeType != DomNodeType.Text))
{
//this can happen when an anchor tag wraps more than just a single, simple text node
//for example when it contains inline elements like <strong>
MessageBox.Show("Can't edit a complex hyperlink");
return;
}
}
else
{
existingHyperlink = null;
url = null;
}
break;
default:
//unexpected
MessageBox.Show("Can't insert a hyperlink when more than one node in the document is selected");
return;
}
//display the modal dialog box
using (FormInsertHyperlink formInsertHyperlink = new FormInsertHyperlink())
{
formInsertHyperlink.url = url;
formInsertHyperlink.visibleText = visibleText;
DialogResult dialogResult = formInsertHyperlink.ShowDialog();
if (dialogResult != DialogResult.OK)
{
//user cancelled
return;
}
//get new values from the dialog box
//the FormInsertHyperlink.onEditTextChanged method assures that both strings are non-empty
url = formInsertHyperlink.url;
visibleText = formInsertHyperlink.visibleText;
}
//need to change href, change text, and possibly delete existing text;
//do this within the scope of a single IEditorTransaction instance so
//that if the user does 'undo' then it will undo all these operations at once, instead of one at a time
using (IEditorTransaction editorTransaction = modelEdit.createEditorTransaction())
{
if (existingHyperlink != null)
{
//changing an existing hyperlink ...
//... change the href attribute value
existingHyperlink.setAttribute("href", url);
//... change the text, by removing the old text node and inserting a new text node
IDomText newDomText = modelEdit.domDocument.createTextNode(visibleText);
IDomNode oldDomText = existingHyperlink.childNodes.itemAt(0);
existingHyperlink.removeChild(oldDomText);
existingHyperlink.insertBefore(newDomText, null);
}
else
{
//creating a new hyperlink
IDomElement newHyperlink = modelEdit.domDocument.createElement("a");
IDomText newDomText = modelEdit.domDocument.createTextNode(visibleText);
newHyperlink.insertBefore(newDomText, null);
newHyperlink.setAttribute("href", url);
//remove whatever was previously selected, if anything
if (!domRange.collapsed)
{
domRange.deleteContents();
}
//insert the new hyperlink
domRange.insertNode(newHyperlink);
}
}
}
}