private async void InsertCampaign_VisibleChanged(object sender, EventArgs e) { if (InsertCampaign.Visible) { CampaignManager.Enabled = false; await Task.Run(() => { cms.InitializeConnection(); managers = cms.GetAllEmployees(); }); foreach (var manager in managers) { CampaignManager.Items.Add(manager.Name); } CampaignManager.Enabled = true; } }