How do I create a C# array using Reflection and only type info? [duplicate]

Question

I can't figure out how to make this work:

object x = new Int32[7]; Type t = x.GetType();  // now forget about x, and just use t from here.  // attempt1  object y1 = Activator.CreateInstance(t); // fails with exception  // attempt2 object y2 = Array.CreateInstance(t, 7);  // creates an array of type Int32[][] ! wrong 

What's the secret sauce? I can make the second one work if I can get the type of the elements of the array, but I haven't figured that one out either.

Answer 1

You need Type.GetElementType() to get the non-array type:

object x = new Int32[7]; Type t = x.GetType(); object y = Array.CreateInstance(t.GetElementType(), 7); 

Alternatively, if you can get the type of the element directly, use that:

Type t = typeof(int); object y = Array.CreateInstance(t, 7); 

Basically, Array.CreateInstance needs the element type of the array to create, not the final array type.