是否可以转换类型的变量：dictionary< int，models.user>到词典< int，object>在C＃？ [英] Is it possible to cast a variable of type: dictionary<int, models.user> to dictionary<int, object> in C#?

问题描述

大家好。我正在开发一个c＃应用程序，其中我有大约15种方法来更新数据库中的条目。所以我想用两个参数创建一个更新方法：Dictionary< int，object>字典和字符串tableName。字典的对象部分将接受不同的ViewModel。这是我的代码：

Hi, everyone. I am working on a c# application where I have about 15 methods that Update entries in the database. So I want to make one method for update with two parameters: Dictionary<int, object> dictionary and string tableName. The 'object' part of the dictionary will accept different ViewModels. Here is my code:

public void UpdateEntriesFromAGivenTable(Dictionary<int, object> dictionary, string tableName)
        {
            foreach (KeyValuePair<int, object> entry in dictionary)
            {
                Dictionary<string, object> dict = GetTypeNamesAndValuesWithReflection(entry.Value);

                foreach (var item in dict)
                {
                    if (item.Value != null && (!string.Equals(item.Key, "id")))
                    {
                        UpdateEntry(tableName, item.Key, item.Value, entry.Key);
                    }
                }
            }
        }

但是当我试图使用上面的方法，我收到参数Dictionary< int，user>下面的红色下划线并且错误消息是：无法从'System.Collections.Generic.Dictionary< int，Models.User>转换到'System.Collections.Generic.Dictionary< int，object> ;.



我尝试过：



我尝试过以下演员：



（字典< int，object>）（用户）



但没有成功。我在谷歌和stackoverflow寻求帮助，但没有找到类似的问题。所以你能告诉我是否可以转换Type：Dictionary< int，Models.User>的变量。到词典< int，object>如果答案是肯定的，怎么做？谢谢。

But when I tried to use the above method, I receive the red underline below the parameter "Dictionary<int, user>" and the error message is: cannot convert from 'System.Collections.Generic.Dictionary<int, Models.User> to 'System.Collections.Generic.Dictionary<int, object>.

What I have tried:

I tried the following cast:

(Dictionary<int, object>)(users)

but without success. I looked for help in google and stackoverflow but did not find a similar issue. So can you tell me is it possible to cast a variable of Type: Dictionary<int, Models.User> to Dictionary<int, object> and if the answer is yes, how to do it? Thanks.

推荐答案

使用泛型

Use generics

public void UpdateEntriesFromAGivenTable<T>(Dictionary<int, T> dictionary, string tableName)
{
    foreach (KeyValuePair<int, T> entry in dictionary)
    {
        Dictionary<string, object> dict = GetTypeNamesAndValuesWithReflection(entry.Value);

        foreach (var item in dict)
        {
            if (item.Value != null && (!string.Equals(item.Key, "id")))
            {
                UpdateEntry(tableName, item.Key, item.Value, entry.Key);
            }
        }
    }
}

你可以打电话它喜欢

You can call it like

Dictionary<int, User> d = new Dictionary<int, User>();

d.Add(1, new User { Name = "A" });
d.Add(2, new User { Name = "B" });

UpdateEntriesFromAGivenTable(d, "");

见这里： C＃cast Dictionary< string，AnyType>到词典< string，对象> （涉及反思） - 堆栈溢出 [ ^ ]

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