used the variable size of array at runtime

I want to create a dynamic array in C# at runtime then use this variable array values:

  int z = 0;
  int k=0;
  int[] err11;
  if (y == 1)
  {
       while(z < laddrslt)
       {
            if (addRs开发者_运维知识库lt[z].Error < 0)
            {
                 err[]=new int[k];

                 err11[k] = item[z].HandleClient ;
                 k++;
             }
             z++;
        }
   }

   if (err11.Length < addRslt.Length)
   {
        //code
   }

You can't resize an array. Use a list instead:

List<int> err11 = new List<int>();
if (y == 1) {
  for (int z = 0, z < addRslt.Length, z++) {
    if (addRslt[z].Error < 0) {
      err11.Add(item[z].HandleClient);
    }
  }
}

if (err11.Count < addRslt.Length) {
    //code
}