Find if 2 strings are anagram or not

/* find if 2 strings are anagram or not like silent and listen*/
string str1 = Console.ReadLine();
string str2 = Console.ReadLine();
bool isAnagram = true;
int strLen = str1.Length;
int[] arr = new int[256];
if(strLen == str2.Length)
{
for (int i = 0; i < strLen; i++)
{
arr[(int)str1[i]]++;
arr[(int)str2[i]]--;
}
foreach (int i in arr)
{
if (i > 0)
{
isAnagram = false;
break;
}
}
}
else
{
isAnagram = false;
}