File Extension

Hi

  How to get file extension . I want if it is .xls then constring should be 

@"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + path + ";Extended Properties=\"Excel 8.0;HDR=Yes;IMEX=1\";";

else

@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + srcFile + ";Extended Properties=\"Excel 12.0 Xml;HDR=YES;IMEX=1\";";

Thanks