C# Foreach 语句不包含 GetEnumerator 的公共定义

C# Foreach statement does not contain public definition for GetEnumerator

提问by Danny

I'm having a problem with a Windows Form application I'm building in C#. The error is stating "foreach statement cannot operate on variables of type 'CarBootSale.CarBootSaleList' because 'CarBootSale.CarBootSaleList' does not contain a public definition for 'GetEnumerator'".

我在使用 C# 构建的 Windows 窗体应用程序时遇到问题。错误指出“foreach 语句不能对类型为‘CarBootSale.CarBootSaleList’的变量进行操作，因为‘CarBootSale.CarBootSaleList’不包含‘GetEnumerator’的公共定义”。

I can't seem to understand what is causing this.

我似乎无法理解是什么导致了这种情况。

This is the code that is throwing up the error:

这是引发错误的代码：

        List<CarBootSaleList> Sortcarboot = new List<CarBootSaleList>();

        foreach (CarBootSale c in carBootSaleList)
        {
            if (c.Charity == "N/A")
            {
                Sortcarboot.Add(carBootSaleList);
                textReportGenerator.GenerateAllReport(Sortcarboot, AppData.CHARITY);
            }
        }

and this is the CarBootSaleList class where it's saying there isn't a GetEnumerator definition:

这是 CarBootSaleList 类，它说没有 GetEnumerator 定义：

public class CarBootSaleList
{

    private List<CarBootSale> carbootsales;

    public CarBootSaleList()
    {
        carbootsales = new List<CarBootSale>();
    }

    public bool AddCarBootSale(CarBootSale carbootsale)
    {
        bool success = true;
        foreach (CarBootSale cbs in carbootsales)
        {
            if (cbs.ID == carbootsale.ID)
            {
                success = false;
            }
        }
        if (success)
        {
            carbootsales.Add(carbootsale);
        }
        return success;
    }

    public void DeleteCarBootSale(CarBootSale carbootsale)
    {
        carbootsales.Remove(carbootsale);
    }

    public int GetListSize()
    {
        return carbootsales.Count();
    }

    public List<CarBootSale> ReturnList()
    {
        return carbootsales;
    }

    public string Display()
    {
        string msg = "";

        foreach (CarBootSale cbs in carbootsales)
        {
            msg += String.Format("{0}  {1}", cbs.ID, cbs.Location, cbs.Date);
            msg += Environment.NewLine;
        }
        return msg;
    }

回答by Grubl3r

You should implement the IEnumerable interface (CarBootSaleList should impl it in your case).

您应该实现 IEnumerable 接口（CarBootSaleList 应该在您的情况下实现它）。

http://msdn.microsoft.com/en-us/library/system.collections.ienumerable.getenumerator.aspx

http://msdn.microsoft.com/en-us/library/system.collections.ienumerable.getenumerator.aspx

But it is usually easier to subclass System.Collections.ObjectModel.Collection and friends

但通常更容易继承 System.Collections.ObjectModel.Collection 和朋友

http://msdn.microsoft.com/en-us/library/system.collections.objectmodel.aspx

http://msdn.microsoft.com/en-us/library/system.collections.objectmodel.aspx

Your code also seems a bit strange, like you are nesting lists?

您的代码似乎也有点奇怪，就像您在嵌套列表一样？

回答by Guish

Your CarBootSaleListclass is not a list. It is a class that contain a list.

你的CarBootSaleList班级不是一个列表。它是一个包含列表的类。

You have three options:

您有三个选择：

Make your CarBootSaleListobject implement IEnumerable

让你的CarBootSaleList对象实现IEnumerable

or

或者

make your CarBootSaleList inherit from List<CarBootSale>

使您的 CarBootSaleList 继承自 List<CarBootSale>

or

或者

if you are lazy this could almost do the same thing without extra coding

如果你很懒，这几乎可以做同样的事情而无需额外的编码

List<List<CarBootSale>>

回答by pescolino

You don't show us the declaration of carBootSaleList. However from the exception message I can see that it is of type CarBootSaleList. This type doesn't implement the IEnumerableinterface and therefore cannot be used in a foreach.

您没有向我们展示carBootSaleList. 但是，从异常消息中我可以看到它的类型为CarBootSaleList。此类型不实现IEnumerable接口，因此不能在 foreach 中使用。

Your CarBootSaleListclass should implement IEnumerable<CarBootSale>:

你的CarBootSaleList班级应该实现IEnumerable<CarBootSale>：

public class CarBootSaleList : IEnumerable<CarBootSale>
{
    private List<CarBootSale> carbootsales;

    ...

    public IEnumerator<CarBootSale> GetEnumerator()
    {
        return carbootsales.GetEnumerator();
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return carbootsales.GetEnumerator();
    }
}

回答by Jonhtra

In foreach loop instead of carBootSaleList use carBootSaleList.data.

在 foreach 循环而不是 carBootSaleList 中使用 carBootSaleList.data。

You probably do not need answer anymore, but it could help someone.

您可能不再需要答案，但它可以帮助某人。