List of type T to Dictionary

I have an object List<T> and a keyfieldName of Type T i am trying to convert this List<T> to an Dictionary<string,double>

for example if Type T is of type Person, i will be given keyfieldName ="UserId"

ListItem1==>    Person
        UserId  1
        Firstname : "John"
        Lastname    "Doe"
ListItem2==>    Person
        UserId  2
        Firstname : "Mark"
        Lastname    "Twain"
ListItem3==>    Person
        UserId  27
        Firstname : "Hello"
        Lastname    "Life"

the result I am expecting would be Dictionary<string,double>, idea is take each property in Type T take its value and append it with :keyfieldName. keyfieldName by itself is excluded from dictionary. All of the property inside Type T would have to be converted to string.

Dictionary should look like this:

"John:1",0
"Doe:1",0
"Mark:2",0
"Twain:2",0
"Hello:27",0
"Life:27",0

What I have tried so far is to loop:

FieldInfo Idfield = typeof(T).GetField(HashKeyFieldName);
foreach (var item in indexItems)
{
    string keyvalue = Idfield.GetValue(item).ToString();

    foreach (var f in typeof(T).GetFields().Where(f => f.Name != HashKeyFieldName))
    {
        string obj =f.GetValue(item).ToString() + ":" + keyvalue;
    }
}

I noticed that List has ToDictionary function; I was wondering if it can be done faster and better, and if so, how?

Jon Skeet
people
quotationmark

If you know the type in advance, I'd just use:

var dictionary = list.Select(x => x.FirstName + ":" + x.UserId)
                     .Concat(list.Select(x => x.LastName + ":" + x.UserId))
                     .ToDictionary(p => p, p => 0);

There'll be one extra Concat call per additional property, but that shouldn't be too bad - again, if you know the class in advance. If you really need to do this with reflection, then the code you've got already is roughly what I'd use - although I'd strongly advise you to use properties rather than fields.

people

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