如何添加一个文本字段，如果已经有一个现有的文本字段在ABCPDF

我能够从ABCPDF支持那里得到答案。正如你所看到的，这不是一个简单的过程。我不确定如果不花几个月的时间研究PDF规范和ABCPDF产品，任何人都能自己解决这个问题。

public FormField AddTextField(string inRect, string inName, string inText)
{
    bool fieldAlreadyExists = mDoc.Form[inName] != null;
    int fieldId = mDoc.AddObject("<</Type /Annot /Subtype /Widget /F 4 /FT /Tx /Ff 4096 /Q 1>>");
    mDoc.SetInfo(fieldId, "/V:Text", inText);
    RegisterField(fieldId, inName, inRect);
    var field = new FormField(fieldId, mDoc);
    if (fieldAlreadyExists)
    {
        InteractiveForm form = new InteractiveForm(mDoc);
        form.AddFieldIntoExistingGroup(field, true);
    }
    return field;
}

private bool AddFieldIntoExistingGroup(FormField field, bool refreshForm)
{
    bool duplicatesFound = false;
    int acroFormID = mDoc.GetInfoInt(mDoc.Root, "/AcroForm:Ref");
    int parentID = mDoc.GetInfoInt(field.Id, "/Parent:Ref");
    ArrayAtom kids;
    if (parentID > 0)
    {
        kids = mDoc.ObjectSoup.Catalog.Resolve(Atom.GetItem(mDoc.ObjectSoup[parentID].Atom, "Kids")) as ArrayAtom;
    }
    else
    {
        kids = mDoc.ObjectSoup.Catalog.Resolve(Atom.GetItem(mDoc.ObjectSoup[acroFormID].Atom, "Fields")) as ArrayAtom;
    }
    Dictionary<string, List<IndirectObject>> items = new Dictionary<string, List<IndirectObject>>();
    for (int i = 0; i < kids.Count; i++)
    {
        IndirectObject io = mDoc.ObjectSoup.Catalog.ResolveObj(kids[i]);
        if (io == null)
        {
            continue; // shouldn't really happen
        }
        string name = mDoc.GetInfo(io.ID, "/T:Text");
        if (!items.ContainsKey(name))
        {
            items[name] = new List<IndirectObject>();
        }
        items[name].Add(io);
    }
    foreach (KeyValuePair<string, List<IndirectObject>> pair in items)
    {
        if (pair.Value.Count > 1)
        {
            duplicatesFound = true;
            // shift field down to be a child of a new field node
            int id = mDoc.AddObject("<< >>");
            if (parentID > 0)
            {
                mDoc.SetInfo(parentID, "/Kids[]:Ref", id);
                mDoc.SetInfo(id, "/Parent:Ref", parentID);
            }
            else
            {
                mDoc.SetInfo(acroFormID, "/Fields[]:Ref", id);
            }
            string[] dictEntries = new[] { "/FT", "/T", "/TU", "/Ff", "/V", "/DV" };
            foreach (IndirectObject io in pair.Value)
            {
                foreach (string dictEntry in dictEntries)
                {
                    string val = mDoc.GetInfo(io.ID, dictEntry);
                    if (!string.IsNullOrEmpty(val))
                    {
                        mDoc.SetInfo(id, dictEntry, val);
                        mDoc.SetInfo(io.ID, dictEntry + ":Del", "");
                    }
                }
                ArrayRemoveOneRefAtom(kids, io.ID);
                mDoc.SetInfo(id, "/Kids[]:Ref", io.ID);
                mDoc.SetInfo(io.ID, "/Parent:Ref", id);
            }
        }
    }
    if ((refreshForm) && (duplicatesFound))
    {
        mDoc.Form.Refresh();
    }
    return duplicatesFound;
}
private static bool ArrayRemoveOneRefAtom(ArrayAtom array, int id)
{
    if (array != null)
    {
        for (int i = 0; i < array.Count; i++)
        {
            RefAtom refAtom = array[i] as RefAtom;
            if ((refAtom != null) && (refAtom.ID == id))
            {
                ArrayRemoveAt(array, i);
                return true;
            }
        }
    }
    return false;
}
private static void ArrayRemoveAt(ArrayAtom array, int index)
{
    if (index == 0)
    { // Workaround for bug in some versions of ABCpdf
        Atom[] copy = new Atom[array.Count];
        array.CopyTo(copy, 0);
        array.Clear();
        for (int i = 1; i < copy.Length; i++)
            array.Add(copy[i]);
    }
    else
    {
        array.RemoveAt(index);
    }
}