Getdata VB.NET function

Question

Getdata VB.NET function

Asked 9 years ago

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I’m trying to create a function to update Datagridview. I added the following code but gave an error "Unable to clear the list"

Code:

    Private Sub GetData()
    Try
        con = New SqlConnection(cs)
        con.Open()
        cmd = New SqlCommand("SELECT nome, matricula, marca, [Licenca-emissao], [licenca-expira] from Clientes order by Nome", con)
        rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection)
        dgw.Rows.Clear()
        While (rdr.Read() = True)
            dgw.Rows.Add(rdr(0), rdr(1))
        End While
        con.Close()
    Catch ex As Exception
        MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
    End Try
End Sub

you are setting your dgw’s Datasource somewhere before?

– Bruno Piovan

2015/11/11 at 18:19
@Brunopiovan did not realize the "SETANDO"

– Abd Domingos

2015/11/11 at 18:27
vc is assigning the previously Datasource property somewhere else?

– Bruno Piovan

2015/11/11 at 18:28
@Brunopiovan Yes, in various Forms

– Abd Domingos

2015/11/11 at 18:30
That’s why you can’t clean the Rows because there is an assigned datasource, you have to clean the "Rows" from your datasource. I will respond with a recommendation.

– Bruno Piovan

2015/11/11 at 18:31
@Brunopiovan am an amateur developer yet, could make it a little easier. And I notice more programming in English

– Abd Domingos

2015/11/11 at 18:33
ok! check These out, Might help http://stackoverflow.com/questions/6184402/how-can-i-clear-rows-in-datagridview-with-c http://stackoverflow.com/questions/18151641/filling-a-datagridview-from-sqlreader

– Bruno Piovan

2015/11/11 at 18:34
Thanks, but this is C#, I’ve never touched C# @Brunopiovan

– Abd Domingos

2015/11/11 at 18:37
I tried using the function datatable.Clear dataGridView.Refresh More didn’t work

– Abd Domingos

2015/11/11 at 18:39

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by Bruno Piovan • **724** points · Answer 1 · 2015-11-11T18:44:07+00:00

Try this:

Private Sub GetData()
    Try
        con = New SqlConnection(cs)
        con.Open()
        cmd = New SqlCommand("SELECT nome, matricula, marca, [Licenca-emissao], [licenca-expira] from Clientes order by Nome", con)
        rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection)

        Dim dt = New DataTable()
        dt.Load(rdr)
        dgw.AutoGenerateColumns = True
        dgw.DataSource = dt
        dgw.Refresh()

        con.Close()
    Catch ex As Exception
        MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
    End Try
End Sub

As I said in the commentary, you cannot clear the lines because you yourself said you are assigning a Datasource earlier, so you need to touch it, and not the lines of your Datagridview.