Thanks ever one a solved it just after i but the question
by add new referance to datacontext like
private void reloadbtn_Click(object sender, RoutedEventArgs e)
{
dbMRCPe.dbmrcpnephrologyEntities ctx2 = new dbMRCPe.dbmrcpnephrologyEntities();
ctx = ctx2;
topicmainViewSource.Source = ctx.topicmains;
}
if I use topicmainViewSource.Source = ctx.topicmains; directly it will not load the new data also I want to use ctx.SaveChanges() allover the code