Импорт данных в SQL server

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я импортирую данные в sql server из CSV файла теперь я получаю эту проблему

String was not recognized as a valid DateTime.Couldn't store <20180526> in Date Column.  Expected type is DateTime.

Что я уже пробовал:

Код добавлен из ответов;

here is my complete code

using System;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Data.OleDb;
using System.IO;
using System.Configuration;



namespace BindGridviewFromCSVFile
{
    public partial class BindGridview : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
       
        }

        protected void btnFileUpload_Click(object sender, EventArgs e)
        {
            
            
            //Creating object of datatable  
            //Upload and save the file.
            //getting full file path of Uploaded file  
            string CSVFilePath = Server.MapPath(FileUpload1.PostedFile.FileName);

            //Reading All text  
            string ReadCSV = File.ReadAllText(CSVFilePath);

            DataTable dt = new DataTable("HR");
            //DataColumn dateColumn = new DataColumn();
            
            //dateColumn.ColumnName = "Date";
            //dt.Columns.AddRange(new DataColumn[5] { new DataColumn("Empcode", typeof(int)),
            //new DataColumn("Days", typeof(int)),
            // new DataColumn("Date", typeof(int)),
            //DateTime Date = Convert.ToDateTime("Date");
        //    table.Columns.Add("SaleDate", typeof(DateTime));


            //  new DataColumn("Time", typeof(int)),
            //   new DataColumn("IN/OUT", typeof(int)),});

            // Create Column 1: SaleDate
       

            DataColumn DaysColumn = new DataColumn();
            // dateColumn.DataType = Type.GetType("System.int");     
            DaysColumn.ColumnName = "Days";

      

            DataColumn dateColumn = new DataColumn();
            dateColumn.DataType = Type.GetType("System.DateTime");
         
            dateColumn.ColumnName = "Date";

            
            
       


            // Create Column 2: ProductName
            DataColumn timeNameColumn = new DataColumn();
            timeNameColumn.ColumnName = "Time";

            // Create Column 3: TotalSales
            DataColumn INOUTColumn = new DataColumn();
          //  totalSalesColumn.DataType = Type.GetType("System.int");
           INOUTColumn.ColumnName = "IN/OUT";

           //  EmpcodeColumn.DataType = Type.GetType("int");
           DataColumn EmpcodeColumn = new DataColumn();
           EmpcodeColumn.ColumnName = "Empcode";

            // Add the columns to the ProductSalesData DataTable
           dt.Columns.Add(DaysColumn);
           dt.Columns.Add(dateColumn);
           dt.Columns.Add(timeNameColumn);
           dt.Columns.Add(INOUTColumn);
           dt.Columns.Add(EmpcodeColumn);
           // Let's populate the datatable with our stats.
           // You can add as many rows as you want here!

           // Create a new row
           //DataRow dailyProductSalesRow = dt.NewRow();
           //dailyProductSalesRow["Empcode"] = "";
           //dailyProductSalesRow["Days"] = "";

           //dailyProductSalesRow["Date"] = DateTime.Today;
           //dailyProductSalesRow["Time"] = "";
           //dailyProductSalesRow["IN/OUT"] = "";



          string csvData = File.ReadAllText(CSVFilePath);
            foreach (string row in csvData.Split('\n'))
            {
                if (!string.IsNullOrEmpty(row))
                {
                    dt.Rows.Add();
                    int i = 0;
                    foreach (string cell in row.Split(','))
                    {
                        dt.Rows[dt.Rows.Count - 1][i] = cell;
                        i++;
                    }
                }
            }

            SqlConnection con = new SqlConnection("Data Source=.;Initial Catalog=Institute;Integrated Security=True");
            //        con.Open();
            {
                using (SqlBulkCopy sqlBulkCopy = new SqlBulkCopy(con))
                {
                    //Set the database table name.
                    sqlBulkCopy.DestinationTableName =

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