使用Oledbconnection时出现编译错误

Question

i am using OleDbConnection for connection string here but I am getting error at line

if (conn.State == ConnectionState.Closed)

Error as CS0019: Operator '==' cannot be applied to operands of type 'System.Data.ConnectionState' and 'ConnectionState'

here is my code

protected void btnSave_Click(object sender, EventArgs e)
{
    DataTable dtExcel = new DataTable();
    dtExcel.Clear();
    string StrCount = String.Empty;
    string connString = "";
    HttpPostedFile File = FileUpload1.PostedFile;
    string strFileType = Path.GetExtension(FileUpload1.FileName).ToLower();
    string path = FileUpload1.PostedFile.FileName;
    string Filename = path.Substring(path.LastIndexOf("\\") + 1, path.Length - path.LastIndexOf("\\") - 1);
    path = Server.MapPath(@"~/Excels/" + "/" + Filename.ToString());

    File.SaveAs(path);
    if (strFileType.Trim() == ".xls")
    {
        connString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + path + ";Extended Properties=\"Excel 8.0;HDR=Yes;IMEX=2\"";
    }
    else if (strFileType.Trim() == ".xlsx")
    {
        connString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties=\"Excel 12.0;HDR=Yes;IMEX=2\"";
    }
    string query = "SELECT * FROM [Sheet 1$]";
    OleDbConnection conn = new OleDbConnection(connString);
    conn.Close();
    if (conn.State == ConnectionState.Closed)
        conn.Open();
    OleDbCommand cmd = new OleDbCommand(query, conn);
    OleDbDataAdapter daExcel = new OleDbDataAdapter(cmd);

    daExcel.Fill(dtExcel);
    conn.Close();}

I dont know why?

I tried the solutions from other link but it didn't helped

Answer 1

It seems to me you have an ambiguous class or property name. ConnectionState appears to have two meanings.

Try to prefix ConnectionState as follows with its full namespace:

if (conn.State == System.Data.ConnectionState.Closed)

Answer 2

After reading your comments on Patrick's answer, I see else is missing here

if (strFileType.Trim() == ".xls")
    {
        connString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + path + ";Extended Properties=\"Excel 8.0;HDR=Yes;IMEX=2\"";
    }
    else if (strFileType.Trim() == ".xlsx")
    {
        connString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + path + ";Extended Properties=\"Excel 12.0;HDR=Yes;IMEX=2\"";
    }

May be connString is left blank as strFileType is not .xls.or .xlsx.