CODEWITHSUNDEEP
c#mysqlwinformslistview
Joel
Joel

Reputation: 6211

avoid deselection upon updating listview in winforms

I have a listView that's pulling information from a MySql-server.

I'm currently using a timer to update this information every 5 sec or so. But everytime updateListView occurs, my selection loses focus. How would i prevent this? I've looked around on stackoverflow but i haven't been able to find a solution that works for me.

Here's my function updateListView that i'm using (fetching data from mySql):

MySqlCommand cmd2 = new MySqlCommand("SELECT * FROM " + selectTable.Text, dbCon.Connection);
try
{
     listView1.Items.Clear(); // suspecting that problem lies here,
                             //  any other way to do this?
     using (MySqlDataReader reader2 = cmd2.ExecuteReader())
     {
         while (reader2.Read())
         {
              ListViewItem item = new ListViewItem(reader2["ID"].ToString());
              item.SubItems.Add(reader2["Name"].ToString());
              item.SubItems.Add(reader2["Age"].ToString());
              item.SubItems.Add(reader2["DiveNr"].ToString());
              item.SubItems.Add(reader2["Difficulty"].ToString());
              item.SubItems.Add(reader2["Points"].ToString());

              listView1.Items.Add(item);
         }
     }
}
catch (Exception ex)
{
     MessageBox.Show("Error updateListView:" + ex.Message);
}

Upvotes: 0

Views: 31

Answers (1)

TaW
TaW

Reputation: 54453

Since you have identifying IDs in your data it will do to store the selected IDs before clearing:

var sel = listView1.SelectedItems.Cast<ListViewItem>().Select(x => x.Name).ToList();

For the Find to work it is best to set the Name property of the ListViewItem to hold those IDs:

ListViewItem item = new ListViewItem(reader2["ID"].ToString());
item.Name = item.Text;

After the new data have been loaded you can then try to re-select each:

foreach (var lvi in sel)
{
    var found = listView1.Items.Find(lvi, false);
    if (found.Length > 0) found[0].Selected = true;
}

You may or may not want to try to reduce flicker during the update by SuspendLayout() and ResumeLayout(); ymmv..

Upvotes: 1

Related Questions