Linq-to-SQL query returns error "Invalid Cast"

Question

Here's my code that returns a list of articles and display them in a listbox. The strange thing is that it is working fine in Visual Studio 2019, but returns an error

Invalid cast

in Visual Studio 2017 !

The error happens at the line ArtListBox.Itemssource...

private void GetArticles()
{
    DataClasses1DataContext dc = new DataClasses1DataContext();

    IOrderedQueryable<FICHES_ARTICLES> art = (from a in dc.PESEES
                                              join p in dc.FICHES_ARTICLES on a.ART_CODE equals p.ART_CODE
                                              where a.PESEE_ST == 0
                                              select p).Distinct().OrderBy(x => x.ART_LIBELLE1);

    ArtListBox.ItemsSource = art;
    ArtListBox.DisplayMemberPath = "ART_LIBELLE1";
    ArtListBox.SelectedValuePath = "ART_CODE";
}

Can someone help me fix this error? I would really appreciate it.

Answer 1

根据您的评论ArtListBox.ItemsSource的类型为string，因此您需要将字符串值分配给ItemsSource属性

IOrderedQueryable<FICHES_ARTICLES> art = (from a in dc.PESEES
                                              join p in dc.FICHES_ARTICLES on a.ART_CODE equals p.ART_CODE
                                              where a.PESEE_ST == 0
                                              select p).Distinct().OrderBy(x => x.ART_LIBELLE1);
ArtListBox.ItemsSource = art.FirstOrDefault();

  

FirstOrDefault()将返回序列的第一个元素   分层a.PESEE_ST == 0，如果找不到元素，则为默认值。