public void InsertFieldWithFieldBuilder()
{
Document doc = new Document();
//Add some text into the paragraph
Run run = DocumentHelper.InsertNewRun(doc, " Hello World!", 0);
FieldArgumentBuilder argumentBuilder = new FieldArgumentBuilder();
argumentBuilder.AddField(new FieldBuilder(FieldType.FieldMergeField));
argumentBuilder.AddText("BestField");
FieldBuilder fieldBuilder = new FieldBuilder(FieldType.FieldIf);
fieldBuilder.AddArgument(argumentBuilder)
.AddArgument("=")
.AddArgument("BestField")
.AddArgument(10)
.AddArgument(20.0)
.AddSwitch("12", "13")
.BuildAndInsert(run);
doc.UpdateFields();
}