Linq ObservableCollection没有返回结果

Question

I am using linq to search product in ObservableCollection, but it does not return any result, for example I have a product name "stack", but when I search "s", it return no result:

private ObservableCollection<Product> _ProductList = new ObservableCollection<Product>();

public ObservableCollection<Product> ProductList 
 { get { return _ProductList; } set { _ProductList = value; } }

I have a textbox, when user type, linq will search product name in the ObservableCollection:

private void productSearch_KeyUp(object sender, KeyEventArgs e)
{
      // Search text
      string productSearchText = productSearch.Text.Trim(); 

      // Search product, return no result
      var search = ProductList.Where(s => s.Name.StartsWith(ProductSearchText));

      search.ToList().ForEach(ProductList.Add);
}

---

Edited:

I notice it is because of letter case problem. I needs to be in uppercase, if the product name is in uppercase, how can I search regarding of letter case?

Answer 1

if the problem is in the case sensetivity you may try to use this

s.Name.ToUppper().StartsWith(ProductSearchText));

or you can try this as well

s.Name.ToUppper().StartsWith(ProductSearchText, StringComparison.OrdinalIgnoreCase));

and you probable want to use search foreach like this

foreach(var item in search)
{

    // get a search item and do what you want with it 

}

Answer 2

To perform case-insensitive search use another overload of this method:

var search = ProductList.Where(s => s.Name.StartsWith   
          (ProductSearchText,StringComparison.CurrentCultureIgnoreCase));