DataGridView add row - vb.net

Question

enter image description hereI am trying to add rows to DataGridView which I suceeded but I have one column unbounded where some math take place.
I want sum of that column below it.
Note: Cell(10) is the one unbounded. In this case I get an error:
Column does not exist
(obviously, it is not in datatable). Here is my code:
Public Sub PrintData()
PrintSQL.ExecQuery("SELECT * FROM Cisnik WHERE Datum = '" &
CDate(LB2.Text).ToString("MM.dd.yyyy") & "'; ")
If PrintSQL.HasException(True) Then Exit Sub
DGV3Print.DataSource = PrintSQL.DBDT
For Each r As DataGridViewRow In DGV3Print.Rows
r.Cells(10).Value = (r.Cells(1).Value - r.Cells(2).Value - r.Cells(4).Value - r.Cells(6).Value)
tb = tb + r.Cells(10).Value
Next
Dim myrow = PrintSQL.DBDT.NewRow
myrow(0) = "CELKEM"
myrow(10) = tb
PrintSQL.DBDT.Rows.Add(myrow)
End Sub
I will appreciate any suggestions

Answer 1

Is your Datum column really stored in the database as a string? You really shouldn't be concatenating strings to build an SQL query. Learn to use parameters. Why take a string, convert it to a Date then back to a string? To solve your problem simply let the database do the work. This just demonstrates the pattern to use. Then bind to your grid.
Dim s = "Select Num1, Num2, Num3, Num1 + Num2 + Num3 As Total From Numbers;"

Answer 2

I solved it this way: It may be amateurish because I am total beginer but it actualy works in way I need. The code is:
Dim myrow = PrintSQL.DBDT.NewRow
Dim i As Integer
i = DGV3Print.Rows.Count - 1
DGV3Print.Rows(i).Cells(0).Value = "CELKEM"
DGV3Print.Rows(i).Cells(10).Value = tb
PrintSQL.DBDT.Rows.Add(myrow)
Anyway thanks for your suggestions

Answer 3

A much simpler way to add a row to a DataGridView is:
DataGridView.Rows.Add({Data1,Data2})

Answer 4

To add a row to a DateGridView, see the example below.
Imports System.Data.SqlClient
Public Class Form1
Dim sCommand As SqlCommand
Dim sAdapter As SqlDataAdapter
Dim sBuilder As SqlCommandBuilder
Dim sDs As DataSet
Dim sTable As DataTable
Private Sub load_btn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles load_btn.Click
Dim connectionString As String = "Data Source=.;Initial Catalog=pubs;Integrated Security=True"
Dim sql As String = "SELECT * FROM Stores"
Dim connection As New SqlConnection(connectionString)
connection.Open()
sCommand = New SqlCommand(sql, connection)
sAdapter = New SqlDataAdapter(sCommand)
sBuilder = New SqlCommandBuilder(sAdapter)
sDs = New DataSet()
sAdapter.Fill(sDs, "Stores")
sTable = sDs.Tables("Stores")
connection.Close()
DataGridView1.DataSource = sDs.Tables("Stores")
DataGridView1.ReadOnly = True
save_btn.Enabled = False
DataGridView1.SelectionMode = DataGridViewSelectionMode.FullRowSelect
End Sub
Private Sub new_btn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles new_btn.Click
DataGridView1.[ReadOnly] = False
save_btn.Enabled = True
new_btn.Enabled = False
delete_btn.Enabled = False
End Sub
Private Sub delete_btn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles delete_btn.Click
If MessageBox.Show("Do you want to delete this row ?", "Delete", MessageBoxButtons.YesNo) = DialogResult.Yes Then
DataGridView1.Rows.RemoveAt(DataGridView1.SelectedRows(0).Index)
sAdapter.Update(sTable)
End If
End Sub
Private Sub save_btn_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles save_btn.Click
sAdapter.Update(sTable)
DataGridView1.[ReadOnly] = True
save_btn.Enabled = False
new_btn.Enabled = True
delete_btn.Enabled = True
End Sub
End Class
http://vb.net-informations.com/datagridview/vb.net_datagridview_database.htm
I'm know you can sum data points in a DataGridView, but I haven't done this for a very long time. Something like this should be pretty close...
Dim sum As Integer = 0
For i As Integer = 0 To dataGridView1.Rows.Count() - 1 Step +1
sum = sum + dataGridView1.Rows(i).Cells(2).Value
Next
textBoxSum.Text = sum.ToString()