Question

我尝试像这样将通用DbSet绑定到Combobox：

public static void BindComboboxByEntity(ComboBox combo, Type type, string displayMember, string valueMember, string orderBy)
{
    if (combo is ComboBox)
        using (var db = new MyDbContext())
        {
            combo.ValueMember = valueMember;
            combo.DisplayMember = displayMember;
            combo.DataSource = db.Set(type).OrderBy(orderBy);
        }
    }

通话：

BindComboboxByEntity(MyCombo, typeof(MyEntity), "name", "id", "name");

但是我知道我需要将IQueryable转换为List才能将数据绑定到Combobox。我该怎么办？

Answer 1

请注意，IQueryable仍表示（通常）尚未执行的“查询”。您需要实际实现查询（例如，使用ToList（））

combo.DataSource = db.Set(type).OrderBy(orderBy).ToList();

注意：您将需要

using System.Linq;

Answer 2

如果您通过Type type，请尝试

var result = db.Set(type).OrderBy(orderByString).ToListAsync();
combo.DataSource = result.Result;

但是我的建议是通过一个通用的类/实体

public static void BindComboboxByEntity<T>(ComboBox combo, string displayMember, string valueMember, string orderBy) where T : class
{
   if (combo is ComboBox)
        using (var db = new MyDbContext())
        {
            combo.ValueMember = valueMember;
            combo.DisplayMember = displayMember;
            combo.DataSource = db.Set<T>().OrderBy(orderBy);
        }

}

然后将其传递为

BindComboboxByEntity<MyEntity>(MyCombo, "name", "id", "name");

实体框架通用DbSet列出

2 个答案: