更新数据时，如何在GridView中使用HTML ENCODE值-错误:集合已修改；枚举操作可能无法执行 [英] How to HTML ENCODE values in a GridView when Updatating - Error: Collection was modified; enumeration operation may not execute

问题描述

我有GridView，我需要HTML ENCODE使用事件处理程序_RowUpdating更新所有值.

I have GridView and I need HTML ENCODE all values being update using Event handler _RowUpdating.

此刻我使用此脚本但收到错误:

At the moment I use this script BUT I receive an error:

Collection was modified; enumeration operation may not execute.

---

有人知道如何使它起作用吗?感谢您的帮助！

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Any idea how to make it works? Thanks for your help!

       foreach (DictionaryEntry entry in e.Keys)
        {
            e.Keys[entry.Key] = Server.HtmlEncode(entry.Value.ToString());              
        }

推荐答案

三个选项:

1)首先获取所有条目的副本，这样您实际上就不会遍历这些条目并随时进行修改.

1) Take a copy of all the entries to start with, so you're not actually iterating over those and modifying them as you go.

2)再次遍历键的副本-避免修改正在遍历的内容.

2) Just iterate over a copy of the keys - again, to avoid modifying what you're iterating over.

3)构建新词典，而不要修改现有词典.

3) Build a new dictionary instead of modifying the existing one.

在此处给出基本代码:

using System;
using System.Collections.Generic;
using System.Linq;

class Test
{    
    static void Main()
    {
        var dict = new Dictionary<string, string>
        {
            { "X", "first" },
            { "Y", "second" },
            { "Z", "third" }
        };

        // INSERT DICTIONARY-CHANGING CODE HERE            

        foreach (var entry in dict)
        {
            Console.WriteLine("{0} = {1}", entry.Key, entry.Value);
        }
    }
}

...并将大写字母"作为简单的测试(只需在实际代码中使用 Server.HtmlEncode )，以下是三个选项(我假设您有您可以使用LINQ):

... and taking "upper-casing" as a simple thing to test (just use Server.HtmlEncode in your real code), here are the three options (I'm assuming you have LINQ available to you):

1)遍历条目的副本:

1) Iterating over a copy of the entries:

    foreach (var entry in dict.ToList())
    {
        dict[entry.Key] = entry.Value.ToUpperInvariant();
    }

2)遍历键的副本:

    foreach (string key in dict.Keys.ToList())
    {
        dict[key] = dict[key].ToUpperInvariant();
    }

3)创建一个新字典(然后将引用分配回 dict 变量):

3) Creating a new dictionary (and then assigning the reference back to the dict variable):

    dict = dict.ToDictionary(entry => entry.Key,
                             entry => entry.Value.ToUpperInvariant());

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