如何在iTextSharp中使用反射取回值

Question

I have a requirement in which user select the size of pdf that is generated dynamically.

To populate all sizes supported by iTextSharp I am enumerating all sizes in a dropdownlist as

      System.Reflection.FieldInfo[] fi = typeof(iTextSharp.text.PageSize).GetFields();
      DropDownList1.DataSource = fi;
      DropDownList1.DataBind();

Every thing is ok till here. Now when user select say letter size, how can i use this information for initializing the document which is initialized like

var document = new Document(PageSize.LETTER);

Currently i am trying to get it like this but its giving compile type error.

PageSize getpsize()
 {
      System.Reflection.FieldInfo[] fi = typeof(iTextSharp.text.PageSize).GetFields();
      int si = DropDownList1.SelectedIndex;
      PageSize p = fi[si];
      return p;
 }

Please help as this is my first serious experience with reflection.

Answer 1

System.Reflection.FieldInfo[] fi = typeof(iTextSharp.text.PageSize).GetFields();

FieldInfo[] is array of fields metadata, not the objects themselves.

So after you get the necessary metadata, you need to get actual field value like this:

FieldInfo field = fi[si];
PageSize size = (PageSize)field.GetValue(null);

GetValue(object) returns actual value of the field. As these fields are static, you pass null, as there is no specific object to query.