Question

I’m currently trying to convert an IEnumerable<T> to a 2-dimensional array of type T2 using an extension method with generic types. You should also be able to choose which properties of T you want to include into that array.

Here’s what I got so far:

public static T2[][] ToMultidimensionalArray<T, T2>(this IEnumerable<T> enumerable, int count, params string[] propNames)
    {
        IEnumerator<T> enumerator = enumerable.GetEnumerator();
        T2[][] resultArray = new T2[count][];
        int i = 0;
        int arrLength = propNames.Length;
        while (enumerator.MoveNext())
        {
            resultArray[i] = new T2[arrLength];
            int j = 0;
            foreach(string prop in propNames)
            {
                resultArray[i][j] = ((T)enumerator.Current).//How do I access the properties?
                j++;
            }
            i++;
        }
        return resultArray;
    }

I’m having a problem accessing the properties of enumerator.Current within the foreach-Loop.

I’m using .NET-Framework 4.0.

Any input would be greatly appreciated.

Thanks,

Dennis

Answer 1

In general, this problem can be solved using reflection:

public static T2[][] ToMultidimensionalArray<T, T2>(
                                                this IEnumerable<T> enumerable,
                                                int count,
                                                params string[] propNames)
{
    T2[][] resultArray = new T2[count][];
    int i = 0;
    int arrLength = propNames.Length;
    foreach (var item in enumerable)
    {
        resultArray[i] = new T2[arrLength];
        int j = 0;
        foreach (string prop in propNames)
        {
            // Get the required property info using reflection
            var propertyInfo = typeof(T).GetProperty(prop);
            // Extract the getter method of the property
            var getter = propertyInfo.GetGetMethod();
            // Invoke the getter and get the property value
            var value = getter.Invoke(item, null);
            // Cast the value to T2 and store in the array
            resultArray[i][j] = (T2) value;
            j++;
        }
        i++;
    }
    return resultArray;
}

I understood the problem as having a Ts collection where these objects have properties of T2 type. The goal is to take the properties of each object and place them in a multidimensional array. Correct me if I’m wrong.