C＃将作为通用对象返回的数组转换为不同的基础类型

Question

I have a C# method which uses object as a generic container to return a data array which could be declared using different data types. Below a simplified example of such a method:

void GetChannelData(string name, out object data)
{
    // Depending on "name", the underlying type of  
    // "data" can be different: int[], byte[], float[]...
    // Below I simply return int[] for the sake of example
    int[] intArray = { 0, 1, 2, 3, 4, 5 };
    data = intArray;
}

I need to convert all the returned array elements to double but so far I could not find a way. Ideally I would like to perform something like:

object objArray;
GetChannelData("test", out objArray);
double[] doubleArray = Array.ConvertAll<objArray.GetType().GetElementType(), double>(objArray, item => (double)item);

Which miserably fails because ConvertAll does not accept types defined at runtime. I have also tried intermediate conversions to a dynamic variable, to no avail.

Is there any way to perform such type conversion in a simple manner?

Answer 1

If you don't know the type at compile time you can try to convert it.

var array = (IEnumerable)objArray;
var doubles = array.OfType<object>().Select(a => Convert.ToDouble(a)).ToArray();

Answer 2

If you don't know the type of array elements at compile-time:

var doubleArray = (objArray as Array).OfType<object>()
    .Select(m => Convert.ToDouble(m)).ToArray();

Answer 3

u can create extension method..

        public static IEnumerable<T> Convert<T>(this IEnumerable source)
        {
           foreach (var item in source)
               yield return (T)System.Convert.ChangeType(item, typeof(T));
        }

using ..

        object objArray;
        GetChannelData("test", out objArray);
        var array = (IEnumerable)objArray;
        var doubleArray = array.Convert<double>().ToArray();