Getting error while import csv file datetime value into SQL server using window application

Question

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error:System.InvalidCastException: 'Specified cast is not valid.'

csv data:

datetime         Miliseconds  MachineAutoStartStop   Pressure
25/10/2022 0:00	    655	       1	                 0.382796
25/10/2022 0:00	    899	       1	                 0.382796
25/10/2022 10:31	37	       1	                 0.382796
25/10/2022 10:31	38	       1	                 0.382796
25/10/2022 10:31	787	       1	                 0.382796

error line: cmd.Parameters.AddWithValue("@DateTime", (DateTime)importRow["DateTime"]);

What I have tried:

C#

private void btnbrowse_Click(object sender, EventArgs e)
        {
            OpenFileDialog ofd = new OpenFileDialog();
            ofd.DefaultExt = ".csv";
            ofd.Filter = "Comma Separated (*.csv)|*.csv";
            ofd.ShowDialog();
            txtfilename.Text = ofd.FileName;

            DataTable dt = new DataTable();
            dataGridView1.DataSource = dt.DefaultView;
            {
              
             }
            }
        private void btnclose_Click(object sender, EventArgs e)
        {
            this.Close();
        }
        private void btnimport_Click(object sender, EventArgs e)
        {
            Cursor = Cursors.WaitCursor;

            DataTable dt = GetDataFromFile();

            if (dt == null) return;

            SaveImportDataToDatabase(dt);

            MessageBox.Show("Data Import success!");
            txtfilename.Text = string.Empty;
            Cursor = Cursors.Default;

        }
        private DataTable GetDataFromFile()
        {
            DataTable dt = new DataTable();

            try
            {
                using (StreamReader sr = new StreamReader(txtfilename.Text))
                {
                    string header = sr.ReadLine();
                    if (string.IsNullOrEmpty(header))
                    {
                        MessageBox.Show("no file data");
                        return null;
                    }
                    string[] headerColumns = header.Split(',');
                    foreach (string headerColumn in headerColumns)
                    {
                        dt.Columns.Add(headerColumn);
                    }

                    while (!sr.EndOfStream)
                    {
                        string line = sr.ReadLine();
                        if (string.IsNullOrEmpty(line)) continue;
                        string[] fields = line.Split(',');
                        DataRow importedRow = dt.NewRow();

                        for (int i = 0; i < fields.Count(); i++)
                        {
                            importedRow[i] = fields[i];
                        }
                        dt.Rows.Add(importedRow);
                        
                    }
                }
            }
            catch (Exception e)
            {
                Console.WriteLine("the file could not be read:");
                Console.WriteLine(e.Message);
            }

            return dt;
        }
        private void SaveImportDataToDatabase(DataTable S2P5)
{
using (SqlConnection conn =New SqlConnection(@"Data Source=BL03\SQLEXPRESS; Initial Catalog=HDB; User Id=sa; Password=00"))
{
    conn.Open();

    foreach (DataRow importRow in S2P5.Rows)
    {
        SqlCommand cmd = new SqlCommand ("INSERT INTO S2P5 (DateTime, Miliseconds, MachineAutoStartStop, Pressure)" + 
                                         "VALUES (@DateTime, @Miliseconds, @MachineAutoStartStop, @Pressure)", conn);
      
        cmd.Parameters.AddWithValue("@DateTime", (DateTime)importRow["DateTime"]);
        cmd.Parameters.AddWithValue("@Miliseconds", importRow["Miliseconds"]);
        cmd.Parameters.AddWithValue("@MachineAutoStartStop", importRow["MachineAutoStartStop"]);
        cmd.Parameters.AddWithValue("@Pressure", importRow["Pressure"]);

        cmd.ExecuteNonQuery();
    }
}

Posted 24-Nov-22 16:27pm

dhivyah jaiya

Updated 25-Nov-22 3:45am

PIEBALDconsult

v2

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OriginalGriff · Accepted Answer · 2022-11-24T21:47:00

Solution 1

YOu can;t cast a random - or more likely string - value to a DateTime, you need to parse it instead.
I'd use DateTime.TryParse[^] or DateTime.TryParseExact[^] to convert the CSV based value, and it is succeeds, pass the resulting DateTime value to SQL.

Posted 24-Nov-22 21:47pm

OriginalGriff

Comments

dhivyah jaiya 29-Nov-22 2:26am

problem solved.Thank you for your solution.

OriginalGriff 29-Nov-22 2:31am

You're welcome!

George Swan · Accepted Answer · 2022-11-24T23:21:00

You have to format the date string so that it can be converted into a DateTime instance. You need to be careful that the milliseconds do not get truncated during the conversion.Something along these lines should do the trick.

C#

string myDateAsString = "25/10/2022 10:31 787";
DateTime myDateAsDateTime = DateTime.ParseExact(myDateAsString, "dd/MM/yyyy HH:mm fff",
                                                           CultureInfo.InvariantCulture);