Cannot apply indexing with [] to an expression of type `object'
The problem is that paredes[i]
returns an object
which is the return type of the ArrayList
indexer. You need to cast this to an ArrayList
to be able to access it:
float a= (float)((ArrayList)paredes[i])[0];
A better solution though is to use generics and populate a List<float>
instead:
List<float> RetornaEmList(float a,float b,float c, float d, float e)
{
return new List<float> { a, b, c, d, e };
}
then paredes
is a List<List<float>>
and your accessor can be changed to:
float a = paredes[i][0];
ArrayList
stores objects without limiting what type those objects are. When you access the objects stored in an ArrayList
, the compiler doesn't know what type they are, so it just gives you type object
.
You're storing an ArrayList
of float
in your outer ArrayList
. Since you're always storing floats, it would be better to use a List<float>
for the inner list, and a List<List<float>>
for the outer list. This way you won't have to type cast from object
:
using System.Collections.Generic;
public List<List<float>> paredes = new List<List<float>>();
Start() {
paredes[0]=RetornaEmList(279,275,0,0,90);
paredes[1]=RetornaEmList(62,275,0,0,0);
paredes[2]=RetornaEmList(62,275,62,0,90);
paredes[3]=RetornaEmList(217,275,62,-62,0);
paredes[4]=RetornaEmList(62,275,279,0,90);
paredes[5]=RetornaEmList(41,275,279,0,0);
paredes[6]=RetornaEmList(279,275,320,0,9);
paredes[7]=RetornaEmList(320,275,0,-279,0);
for (int i=0;i<paredes.Length;i++)
{
float a=paredes[i][0];
float b=paredes[i][1];
float c=paredes[i][2];
float d=paredes[i][3];
float e=paredes[i][4];
}
}
List<float> RetornaEmList(float a,float b,float c, float d, float e)
{
return new List<float> { a, b, c, d, e };
}
Since the inner list always has 5 floats, you could also use a float[]
instead of a List<float>
If you just want to make the code work without moving from ArrayList
to List
, you need an additional cast:
float a = (float)((ArrayList)paredes[i])[0];
But it's a lot cleaner just to use List<float>
instead.