Question

Here comes the trouble.
I want to delete all rows from datagridview.
This how i add rows:

private void ReadCompleteCallback(object clientHandle, Opc.Da.ItemValueResult[]     results)
{
    foreach (Opc.Da.ItemValueResult readResult in results)
    {
        dataGridView1.Invoke(new MethodInvoker(() => dataGridView1.Rows.Add(readResult.ItemName, readResult.Quality, readResult.Timestamp,readResult.Value)));        
    }
}                              

And its how i clear gridview:

private void treeView1_SelectionsChanged(object sender, EventArgs e)
{
    dataGridView1.Rows.Clear();
    items = new Opc.Da.Item[treeView1.SelectedNodes.Count]; 
    foreach (TreeNode x in treeView1.SelectedNodes) {
        items[treeView1.SelectedNodes.IndexOf(x)] = new Opc.Da.Item();
        items[treeView1.SelectedNodes.IndexOf(x)].ItemName = x.Text; 
    }

    group.AddItems(items);
    group.Read(group.Items, 123, new Opc.Da.ReadCompleteEventHandler(ReadCompleteCallback), out req);
}

in debug i see that dataGridVIew1.Rows.Count=0, but on form, grid doesnt become clear. what a point?
on each selection in tree, i want to see new rows in table.

Answer 1

I’m betting you just need to refresh the datagrid. Try this:

dataGridView1.Rows.Clear();
dataGridView1.Refresh();

If this works… you might want to rethink this part of your application.