excel connection string

Question

hi every body 

I try to check excel file on my check i make connection string

why it cant read ConnectionString varible and gets  me error ?? 

this my code

 

string excelexc = DropDown.SelectedValue;

string fileexc = Path.GetExtension(excelexc);

string ConnectionString;

string path;

switch (fileexc)

{

case ".xls":

path = Server.MapPath("~/Schoolresult/" + DropDown.SelectedValue);

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

break;

case ".xlsx":

path = Server.MapPath("~/Schoolresult/" + DropDown.SelectedValue);

ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties=\"Excel 12.0;ReadOnly=False;HDR=Yes;\"";

break;

}

OleDbConnection connExcel = new OleDbConnection(ConnectionString);

OleDbCommand cmdExcel = new OleDbCommand();

 

 try

{

    //my code goes  here on connection string kind

}