绑定通用列表<string>到一个组合框

Question

我有一个 ComboBox，我想将一个通用列表绑定到它。 谁能看出为什么下面的代码不起作用？ 绑定源中有数据，但不会填充 ComboBox 数据源。

FillCbxProject(DownloadData Down)
{
  BindingSource bindingSource = new BindingSource();
  bindingSource.DataSource = Down.ProjectList;
  cbxProjectd.DataSource = bindingSource;
}

附带说明：传递类的实例是否不好？

谢谢！

Answer 1

您需要调用 Bind 方法：

cbxProjectd.DataBind();

如果这是针对 winforms，那么你需要确保你所拥有的被调用，以下工作：

BindingSource bs = new BindingSource();
bs.DataSource = new List<string> { "test1", "test2" };
comboBox1.DataSource = bs;

虽然您可以直接使用列表设置 ComboBox 的数据源。

Answer 2

这是简单的方法（它工作正常）：

List<string> my_list = new List<string>();
my_list.Add("item 1");
my_list.Add("item 2");
my_list.Add("item 3");
my_list.Add("item 4");
my_list.Add("item 5");
comboBox1.DataSource = my_list;

Answer 3

这是一种不使用 BindingSource 的相当简单的方法：

首先，将字符串的通用列表添加到“consts/utils”类中：

public static List<string> Months = new List<string>
{
   "Jan",
   "Feb",
   "Mar",
   "Apr",
   "May",
   "Jun",
   "Jul",
   "Aug",
   "Sep",
   "Oct",
   "Nov",
   "Dec"
};

以下是将这些字符串添加到组合框的方法：

comboBoxMonth.Items.AddRange(UsageRptConstsAndUtils.Months.ToArray<object>());

Answer 4

BindingSource bs = new BindingSource();
bs.DataSource = getprojectname();
comboBox1 = new ComboBox();
comboBox1.DataSource = bs;

Answer 5

使用上面 Yuriy Faktorovich 的代码作为基础，这里是如何获取给定周数的 LongDateString 格式的日期列表，并将它们分配给组合框。 这使用“星期一”，但您可以简单地用任何其他 DOW 替换“星期一”以满足您的目的：

private void PopulateSchedulableWeeks()
{
    int WEEKS_COUNT = 13;
    List<String> schedulableWeeks = PlatypusUtils.GetWeekBeginnings(WEEKS_COUNT).ToList();
    BindingSource bs = new BindingSource();
    bs.DataSource = schedulableWeeks;
    comboBoxWeekToSchedule.DataSource = bs;
}

public static List<String> GetWeekBeginnings(int countOfWeeks)
{
    // from http://stackoverflow.com/questions/6346119/datetime-get-next-tuesday
    DateTime today = DateTime.Today;
    // The (... + 7) % 7 ensures we end up with a value in the range [0, 6]
    int daysUntilMonday = ((int)DayOfWeek.Monday - (int)today.DayOfWeek + 7) % 7;
    DateTime nextMonday = today.AddDays(daysUntilMonday);

    List<String> mondays = new List<string>();
    mondays.Add(nextMonday.ToLongDateString());

    for (int i = 0; i < countOfWeeks; i++)
    {
        nextMonday = nextMonday.AddDays(7);
        mondays.Add(nextMonday.ToLongDateString());
    }
    return mondays;
}

...而且，如果您也想将实际日期添加到组合框中，您可以使用像这样的字典：

    int WEEKS_TO_OFFER_COUNT = 13;
    BindingSource bs = new BindingSource();
    Dictionary<String, DateTime> schedulableWeeks = AYttFMConstsAndUtils.GetWeekBeginningsDict(WEEKS_TO_OFFER_COUNT);             bs.DataSource = schedulableWeeks;
    comboBoxWeekToSchedule.DataSource = bs;
    comboBoxWeekToSchedule.DisplayMember = "Key";
    comboBoxWeekToSchedule.ValueMember = "Value";

public static Dictionary<String, DateTime> GetWeekBeginningsDict(int countOfWeeks)
{
    DateTime today = DateTime.Today;
    // The (... + 7) % 7 ensures we end up with a value in the range [0, 6]
    int daysUntilMonday = ((int)DayOfWeek.Monday - (int)today.DayOfWeek + 7) % 7;
    DateTime nextMonday = today.AddDays(daysUntilMonday);

    Dictionary<String, DateTime> mondays = new Dictionary<String, DateTime>();
    mondays.Add(nextMonday.ToLongDateString(), nextMonday);

    for (int i = 0; i < countOfWeeks; i++)
    {
        nextMonday = nextMonday.AddDays(7);
        mondays.Add(nextMonday.ToLongDateString(), nextMonday);
    }
    return mondays;
}

Answer 6

如果有人发现此死灵线程，请确保您的列表不包含空项目。 否则绑定将无声无息地失败！

//This will not work!
comboBox1.DataSource = new List<string> { "test1", null, "test2" };

//This is legit!
comboBox1.DataSource = new List<string> { "test1", "", "test2" };