How to hydrate a Dictionary with the results of async calls?

Question

Suppose I have code that looks like this:

public async Task DoSomethingReturnString(int n) { ... }
int[] numbers = new int[] { 1, 2 , 3};
         


        

Answer 1

If calling from an asynchronous method, you can write a wrapper method that creates a new dictionary and builds a dictionary by iterating over each number, calling your DoSomethingReturnString in turn:

public async Task CallerAsync()
{
    int[] numbers = new int[] { 1, 2, 3 };
    Dictionary dictionary = await ConvertToDictionaryAsync(numbers);
}

public async Task> ConvertToDictionaryAsync(int[] numbers)
{
    var dict = new Dictionary();

    for (int i = 0; i < numbers.Length; i++)
    {
        var n = numbers[i];
        dict[n] = await DoSomethingReturnString(n);
    }

    return dict;
}