title: No overload for method takes 1 argument error
body: <p>I'm trying to add up all my values of listbox1 but I get an error message.</p>
  
  <pre><code>private void button1_Click(object sender, EventArgs e)
      {
          decimal sum = 0;
          textBox1.Text = Convert.ToString(sum);
          Listbox1opgeteld(sum); //*this is the error
  
      }
      public decimal Listbox1opgeteld(int random, decimal sum)
      {
  
          for (int i = 0; i &lt; listBox1.Items.Count; i++)
          {
              Convert.ToInt32(listBox1.Items);
              sum += Convert.ToDecimal(listBox1.Items[i].ToString());
  
          }
          return sum;
  
      }
  </code></pre>
  
  <p>I tried other question threads but can't find an answer, would really appreciate your help!</p>