pdf到xfdf不会导出注释并创建1kb文件

Question

此处显示的代码正在创建xfdf文件，但未从pdf中获取注释

CAcroAVDoc g_AVDocNew = null;
CAcroPDDoc pdDoc;
object jsAcroObj
Type acroappl = Type.GetTypeFromProgID("AcroExch.AVDoc", true);
g_AVDocNew = (Acrobat.CAcroAVDoc)Activator.CreateInstance(acroappl);
g_AVDocNew.Open(filePath, "");
pdDoc = (CAcroPDDoc)g_AVDocNew.GetPDDoc();
jsAcroObj = pdDoc.GetJSObject();
//jsAcroObj.exportAsXFDF(true, false, VariantType.null, @"D:\Bizcardxf2.XFDF", true);
Type T = jsAcroObj.GetType();
//jsObj.exportAsXFDF(true, false, VariantType.null, @"D:\Bizcardxf2.XFDF", true);

object[] argumentsComments = new object[] { "true", "false", "null", (filePath.Replace(".pdf", 
".XFDF")), "true" };
T.InvokeMember("exportAsXFDF", BindingFlags.InvokeMethod | BindingFlags.Public | 
BindingFlags.Instance,null, jsAcroObj, argumentsComments);