这里有一种通过索引进行更新的方法，就像foo[x] = 9，其中x是键，9是值

var views = new Dictionary<string, bool>();

foreach (var g in grantMasks)
{
    string m = g.ToString();
    for (int i = 0; i <= m.Length; i++)
    {
        views[views.ElementAt(i).Key] = m[i].Equals('1') ? true : false;
    }
}

通过将键作为索引访问是可能的

例如:

Dictionary<string, int> dictionary = new Dictionary<string, int>();
dictionary["test"] = 1;
dictionary["test"] += 1;
Console.WriteLine (dictionary["test"]); // will print 2

使用LINQ:访问字典键并更改值

Dictionary<string, int> dict = new Dictionary<string, int>();
dict = dict.ToDictionary(kvp => kvp.Key, kvp => kvp.Value + 1);

你也可以使用这个方法:

Dictionary<int,int> myDic = new();
if (myDic.ContainsKey(1))
{
    myDic[1] = 1234; // or use += to update it 
}

或按值:

if (myDic.ContainsValue(1))
{
    //do something ... 
}

这可能对你有用:

场景1:基本类型

string keyToMatchInDict = "x";
int newValToAdd = 1;
Dictionary<string,int> dictToUpdate = new Dictionary<string,int>{"x",1};

if(!dictToUpdate.ContainsKey(keyToMatchInDict))
   dictToUpdate.Add(keyToMatchInDict ,newValToAdd );
else
   dictToUpdate[keyToMatchInDict] = newValToAdd; //or you can do operations such as ...dictToUpdate[keyToMatchInDict] += newValToAdd;

场景2:我用于List as Value的方法

int keyToMatch = 1;
AnyObject objInValueListToAdd = new AnyObject("something for the Ctor")
Dictionary<int,List<AnyObject> dictToUpdate = new Dictionary<int,List<AnyObject>(); //imagine this dict got initialized before with valid Keys and Values...

if(!dictToUpdate.ContainsKey(keyToMatch))
   dictToUpdate.Add(keyToMatch,new List<AnyObject>{objInValueListToAdd});
else
   dictToUpdate[keyToMatch] = objInValueListToAdd;

希望对需要帮助的人有用。

只需指向字典中给定的键并赋一个新值:

myDictionary[myKey] = myNewValue;