c# specified cast is not valid while assigning mshtml.HTMLDocument.frames

问题

I'm developing an IE BHO, While accessing frames in a html document i'm getting this error

Here is the code.

foreach (SHDocVw.InternetExplorer objExplorer in objShellWins)
{
   if (objExplorer.Document is HTMLDocument)
   {
      objDocument = (mshtml.HTMLDocument)objExplorer.Document;
      mshtml.HTMLDocument doc = (mshtml.HTMLDocument)objExplorer.Document;
      mshtml.FramesCollection frames = (mshtml.FramesCollection)doc.frames;  //Exception at this line
   }
}

what is the issue here ?

回答1:

OK people i got it solved by setting [STAThread] at function calling

来源：https://stackoverflow.com/questions/19180191/c-sharp-specified-cast-is-not-valid-while-assigning-mshtml-htmldocument-frames