delay while opening view in wpf application - wpf

Question

We are developing application using WPF,material design and MS-Access 2007 as Back End. Now we are facing problem of application slow down while opening single view ,that particular view have 16 combo's which fill. It take 7 seconds for process, following code used for bind combo box item source
List<ComboBind> values = new List<ComboBind>();
try
{
using (var oleDbCommand = new OleDbCommand())
{
oleDbCommand.CommandText = query ;
oleDbCommand.Connection = Connection.con;
var sql = query;
var oleDbDataReader = oleDbCommand.ExecuteReader();
while (oleDbDataReader.Read())
{
ComboBind b = new ComboBind();
b.id = oleDbDataReader[0].ToString().ToInt();
b.name = oleDbDataReader[1].ToString();
values.Add(b);
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}

Answer 1

It looks like you are trying to load data in UI thread during view initialization and this is the reason of the issue. Either do loading of data in background thread or do it before opening the view.
Simple code snippet for loading data in separate task:
//Might be your view code behind or
//ViewModel if you are using MVVM
public class ViewCodeBehind
{
public List<ComboBind> ComboItems { get; set; }
public void Initialize()
{
//start bacground task for data loading
var comboQuery = "select *from data";
Task.Run(() => LoadItems(comboQuery));
}
public void LoadItems(string query)
{
List<ComboBind> values = new List<ComboBind>();
try
{
using (var oleDbCommand = new OleDbCommand())
{
oleDbCommand.CommandText = query;
oleDbCommand.Connection = Connection.con;
var sql = query;
var oleDbDataReader = oleDbCommand.ExecuteReader();
while (oleDbDataReader.Read())
{
ComboBind b = new ComboBind();
b.id = oleDbDataReader[0].ToString().ToInt();
b.name = oleDbDataReader[1].ToString();
values.Add(b);
}
}
//use dispatcher to pass data back to UI thread
System.Windows.Threading.Dispatcher.CurrentDispatcher.BeginInvoke(
new Action(() =>
{
ComboItems = values;
}));
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
}