C＃：如何删除IEnumerable中的项目

Question

I was making a custom grid that accepts an IEnumerable as an Itemsource. However I was not able to remove an Item inside the itemsource during delete method. Will you guys be able to help me using the code below?

static void Main(string[] args)
{
    List<MyData> source = new List<MyData>();
    int itemsCount = 20;
    for (int i = 0; i < itemsCount; i++)
    {
       source.Add(new MyData() { Data = "mydata" + i });
    }

    IEnumerable mItemsource = source;
    //Remove Sample of an mItemSource
    //goes here ..
}

public class MyData { public string Data { get; set; } }

Answer 1

You can't. IEnumerable (and its generic counterpart IEnumerable<T> ) is for just that - enumerating over the contents of some collection. It provides no facilities for modifying the collection.

If you are looking for an interface that provides all the typical means of modifying a collection (eg. Add, Remove) then have a look at ICollection<T> or IList<T> if you need to access elements by index.

Or, if your goal is to provide an IEnumerable to something, but with some items removed, consider Enumerable.Except() to filter them out ( as it is enumerated ).

Answer 2

Use while loop to traverse the list whilst delete.

int i = 0;
while(i < source.Count){
    if(canBeRemoved(source[i])){
        source.RemoveAt(i);
    }else{
        i++;    
    }
}

Answer 3

I was able to remove Item from the Itemsource using dynamic

    static void Main(string[] args)
    {

        List<MyData> source = new List<MyData>();
        int itemsCount = 20;
        for (int i = 0; i < itemsCount; i++)
        {
            source.Add(new MyData() { Data = "mydata" + i });
        }

        IEnumerable mItemsource = source;

        //Remove Sample of an mItemSource

        dynamic d = mItemsource;
        d.RemoveAt(0);

        //check data
        string s = source[0].Data;
    }
    public class MyData { public string Data { get; set; } }