Visual Studio C# datagridview to database

Question

I'm trying to save data from datagridview to database. I keep on getting a

NullReferenceException: Object reference not set to an instance of an object

try 
{           
    foreach (DataGridViewRow row in dataGridView2.Rows)
    {            
        using ( conn = new SqlConnection(constring))
        {
            using (SqlCommand cmd = new SqlCommand("INSERT INTO tbl_Students_Marks VALUES(@Student, @T1, @T2, @T3, @T4)", conn))
            {
                cmd.Parameters.AddWithValue("@Student", (row.Cells["Student Number"].Value).ToString());
                cmd.Parameters.AddWithValue("@T1", row.Cells["Test 1"].Value);
                cmd.Parameters.AddWithValue("@T2", row.Cells["Test 2"].Value);
                cmd.Parameters.AddWithValue("@T3", row.Cells["Test 3"].Value);
                cmd.Parameters.AddWithValue("@T4", row.Cells["Test 4"].Value);
                conn.Open();
                cmd.ExecuteNonQuery();
                conn.Close();

Can you provide line number where you got this error? – Artem Kulikov Aug 03 '15 at 04:49 — Artem Kulikov, Aug 03 '15 at 04:49
use index number instead of index name – dada Aug 03 '15 at 05:32 — dada, Aug 03 '15 at 05:32

score 1 · Answer 1 · answered Aug 03 '15 at 05:00

hmmm try this codes

try 
{           
foreach (DataGridViewRow row in dataGridView2.Rows)
{            
    using ( conn = new SqlConnection(constring))
    {
        using (SqlCommand cmd = new SqlCommand(constring))
        {
            cmd.Connection = con;
            cmd.CommandText = "INSERT INTO tbl_Students_Marks VALUES(@Student, @T1, @T2, @T3, @T4)";
            cmd.CommandType = CommandType.Text
            cmd.Parameters.AddWithValue("@Student", (row.Cells["Student Number"].Value).ToString());
            cmd.Parameters.AddWithValue("@T1", row.Cells["Test 1"].Value);
            cmd.Parameters.AddWithValue("@T2", row.Cells["Test 2"].Value);
            cmd.Parameters.AddWithValue("@T3", row.Cells["Test 3"].Value);
            cmd.Parameters.AddWithValue("@T4", row.Cells["Test 4"].Value);
            conn.Open();
            cmd.ExecuteNonQuery();
            conn.Close();

i hope it helps you

it still giving me the same exception – M_Magz Aug 03 '15 at 05:05 — M_Magz, Aug 03 '15 at 05:05

Artem Kulikov · Accepted Answer · 2015-08-03T05:25:54.007

1

Looks like your row value is empty.

Try to replace your line 9 with this code:

            var studentNumber = row.Cells["Student Number"].Value
            if (studentNumber == null || studentNumber is DBNull)
              continue;
            cmd.Parameters.AddWithValue("@Student", studentNumber.ToString());

edited Aug 03 '15 at 05:25

answered Aug 03 '15 at 05:07

Artem Kulikov

2,250
19
32

@ArtemNow it giving me this error: ***The parameterized query '(@Student nvarchar(4000),@T1 nvarchar(4000),@T2 nvarchar(4000),@' expects the parameter '@T1', which was not supplied.*** – M_Magz Aug 03 '15 at 05:17
Line number with error again please (after your inserted my code). – Artem Kulikov Aug 03 '15 at 05:32

Salah Akbari · Answer 3 · 2015-08-03T05:22:15.783

1

You should remove the empty row from the bottom of your DataGridView first. this is why you can not insert last row. like this (Set AllowUserToAddRows to False in the DataGridView Properties or Add dataGridView2.AllowUserToAddRows = false; in your filling DataGridView method):

dataGridView2.DataSource = ds.Tables[0];
dataGridView2.AllowUserToAddRows = false;

Then rest of your code to INSERT.

edited Aug 03 '15 at 05:22

answered Aug 03 '15 at 05:16

Salah Akbari

39,330
10
79
109

Visual Studio C# datagridview to database

3 Answers3