update row from datagridview to database - vb.net

Question

I have a script to update the value from datagridview to database.
I do use a button insert ToolStripButton but it is not working.
Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
conn = New SqlConnection("")
conn.Open()
Dim query As [String] = "SELECT * FROM dtaTraLoiChoVanBan"
da = New SqlDataAdapter(query, conn)
Dim cb As New SqlCommandBuilder(da)
dt = New DataTable()
da.Fill(dt)
C1FlexGrid1.DataSource = dt
conn.Close()
End Sub
Private Sub ToolStrip1_ItemClicked(ByVal sender As System.Object, ByVal e As System.Windows.Forms.ToolStripItemClickedEventArgs) Handles ToolStrip1.ItemClicked
Select Case e.ClickedItem.Name
Case "ToolStripButton1" '---> button insert
da.Update(dt)
End Select
End Sub

Answer 1

I think your code will reload the grid every time and wipe any changes your user is adding. Try running the grid binding only the first time, by checking for Page.IsPostBack(). You also never used the CommandBuilder to generate an INSERT statement.
Private Sub Form2_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
conn = New SqlConnection("") 'blank connection string won't really work
conn.Open()
Dim query As [String] = "SELECT * FROM dtaTraLoiChoVanBan"
da = New SqlDataAdapter(query, conn)
Dim cb As New SqlCommandBuilder(da)
cb.GetInsertCommand()
dt = New DataTable()
da.Fill(dt)
conn.Close()
If Not Page.IsPostBack() Then
C1FlexGrid1.DataSource = dt
End If
End Sub

Answer 2

I had same problem. I just added validate to solve it.
Private Sub ToolStripButton5_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ToolStripButton5.Click
Me.Validate()
DataGridView1.EndEdit()
da.Update(dt)
MsgBox("Data Updated!!")
Me.BindGrid()
End Sub