Excel data validate with Database data

I need a validation before Insert data in database, when i upload excel file it check excel column usercode data match with database usercode Column.If true then go to InsertData(); if False return a error, Usercode is not exist, Below i Mention th code,

 

ALTER proc [dbo].[Check]
(
   
    @UserCode varchar(50),
   
    @statCode int OUTPUT
    )
AS

  if not exists (select UserCode from Employee where UserCode=@UserCode  )
 
 
  BEGIN

   
    SET @statCode
 END



 private void CheckData()
        {
            String path = Server.MapPath("~/ExcelFile/");
            String fullPath = path + FileUpload.FileName;
            string connString = "";
            string strFileType = Path.GetExtension(FileUpload.FileName).ToLower();
            FileUpload.PostedFile.SaveAs(fullPath);
            string Excel = FileUpload.PostedFile.FileName;
            //Connection String to Excel Workbook
            if (strFileType.Trim() == ".xls")
            {
                connString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + fullPath + ";Extended Properties=\"Excel 8.0;HDR=Yes;Persist Security Info = False;IMEX=2\"";
            }
            else if (strFileType.Trim() == ".xlsx")
            {
                connString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + fullPath + ";Extended Properties=\"Excel 12.0;HDR=Yes; Persist Security Info = False;IMEX=2\"";
            }

            OleDbConnection conn = new OleDbConnection(connString);
            if (conn.State == ConnectionState.Closed)
                conn.Open();
            OleDbCommand cmd = new OleDbCommand("SELECT * FROM [Sheet1$]", conn);

            OleDbDataReader dr = cmd.ExecuteReader();
          
            while (dr.Read())
            {
                string UserCode1 = dr[0].ToString();
              

                SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["abc"].ConnectionString);
                con.Open();
                SqlCommand cmd2 = new SqlCommand();

                cmd2.Connection = con;
                cmd2.CommandType = CommandType.StoredProcedure;
                cmd2.CommandText = "check";
                cmd2.Parameters.AddWithValue("@UserCode", UserCode1);
               
                SqlParameter OutputParam = cmd2.Parameters.Add("@statCode", SqlDbType.Int);
                OutputParam.Direction = ParameterDirection.Output;
               int statCode = Convert.ToInt32(cmd2.Parameters["@statCode"].Value.ToString());
              
                cmd2.ExecuteNonQuery();
                con.Close();
                Response.Write(statCode);
            }


            conn.Close();
            conn.Dispose();
            File.Delete(fullPath);
          

        }

protected void Import_Click(object sender, EventArgs e)
        {

           
            CheckData();
           InsertData();
          BindGrid();

        }