private void userCoding_LostFocus(object sender, RoutedEventArgs e)
{
if (userCoding.Text.Trim() == "")
{
codingError.Content = "用户编号必须填写！";
}
else
{
using (ExpressDBContext db = new ExpressDBContext()) {
var query = from u in db.User
where u.Coding == userCoding.Text.Trim()
select u;
if (query.Count() == 0)
{
codingError.Content = "该用户编号不存在";
}
else
{
codingError.Content = "";
}
}
}
}
