How to convert object to object[]

Question

I have an object whose value may be one of several array types like int[] or string[], and I want to convert it to a string[]

Answer 1

void Do(object value)
{
    if (value.GetType().IsArray)
    {
       string[] strings = ((object[]) value).Select(obj => Convert.ToString(obj)).ToArray();
    }
}

Answer 2

.ToArray makes multiple memory allocations in most cases, but there are few ways around it:

object value = new[] { 1, 2.3 };

IList list = value as IList;
string[] strings = new string[list.Count];

for (int i = 0; i < strings.Length; i++)
    strings[i] = Convert.ToString(list[i]);

In most cases that might be a bit overkill and waste of vertical space, so I would use something like the accepted answer with an optional null-conditional operator ? to check if the source is array:

string[] strings = (value as Array)?.Cast<object>().Select(Convert.ToString).ToArray();

Answer 3

You don't need to convert it to an array and then use LINQ. You can do it in a more streaming fashion, only converting to an array at the end:

var strings = ((IEnumerable) value).Cast<object>()
                                   .Select(x => x == null ? x : x.ToString())
                                   .ToArray();

(Note that this will preserve nulls, rather than throwing an exception. It's also fine for any IEnumerable, not just arrays.)

Answer 4

The solution below is in JAVA

public static Objects[] convertObjectToObjectArray(){
    Objects firstObject = new Object();

    return new Object[]{firstObject};
}

In the above return statement, you are converting an object to an object array.