C＃Linq-組合框未填充

Question

我對comboBoxContainer有問題。 填充comboBoxategory和comboBoxMarket ，不填充comboBoxContainer 。
selected.Container具有正確的變量，但組合框未獲取此變量。

private void listBoxProducts_SelectedIndexChanged(object sender, EventArgs e)
{
    try
    {
        ProductList_Variables selected = ProductList_Variables)listBoxProducts.SelectedItem;

        textBoxProduct.Text = selected.Product;
        comboBoxCategory.SelectedItem = selected.Category;
        comboBoxMarket.SelectedItem = selected.Market;
        comboBoxContainer.SelectedItem = selected.Container;
        textBoxPrice1.Text = selected.Price.ToString();
    }
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
}
class ProductList_Variables
{
    public int Id { get; set; }
    public string Product { get; set; }
    public string Category { get; set; }
    public string Size { get; set; }
    public string Market { get; set; }
    public string ProductName { get { return Product + " - " + Category + " - Size: " + Size +", Market: "+ Market; } }
    public string Flavour { get; set; }
    public decimal Price { get; set; }
    public string Container { get; set; }
    public int IdContainer { get; set; }


}
void Fillcombo()// is filling the combobox
{
    try
    {
        using (var db = new GelatoProjectDBEntities())
        {
            var products = (from x in db.ProductsLists
                            select new ProductList_Variables { Id = x.Id, Product = x.Product, Category = x.Category, Size = x.Size, Market = x.Market, Container=x.Container, Price=x.Price, IdContainer=x.IdContainer }
                            ).OrderBy(c => c.Product).ToArray();
            listBoxProducts.Items.AddRange(products);
            listBoxProducts.DisplayMember = "ProductName";
            listBoxProducts.ValueMember = "Id";
            var goods = (from x in db.Goods
                         select new ProductList_Variables { Id = x.Id, Product=x.item, Container = x.item}
                         ).OrderBy(c => c.Product).ToArray();

           comboBoxContainer.Items.AddRange(goods);
           comboBoxContainer.DisplayMember = "Product";
           comboBoxContainer.ValueMember = "Id";
       }
   }
   catch (Exception ex)
   {
       MessageBox.Show(ex.Message);
   }
    }

Answer 1

看來您的comboBoxContainer充滿了對象，而不是字符串，因此分配時應該匹配該對象。

嘗試更換線

        comboBoxContainer.SelectedItem = selected.Container;

如下

        comboBoxContainer.SelectedItem =
            comboBoxContainer.Items.OfType<ProductList_Variables>().SingleOrDefault(x => x.Container == selected.Container);

Answer 2

當屬性容器包含值（comboBoxContainer的數據元素的屬性ID）時，可以使用

comboBoxContainer.SelectedValue = selected.Container;