C# object[] array getlength?

Hello what is the equivalent of getlenght on an object array it only seems to work with basic arrays like int,double,float,string etc.

int[,] myInts = new int[20,20];

myObect[,] ob = new myObject[20,20]

for (int i = 0; i < myInts.getLength(1);i++) {
    //do some stuff
}

//dosent work whats the equivalent of get length?
for (int z= 0; i < ob.getLength(1);z++) {
    //do some stuff
}

It doesn’t matter what type the array is; the method for getting the length of one dimension is GetLength. (Not “getLength”.)