ArgumentOutOfRangeException and updateControls method

I am just a student begining to study C#, so I apologize if my questions are not very clear. I am stuck for the answer. I don't know how to code the ArgumentOutofRangeException, so the user doesn't go beyond the edges of the Lists. I have 2 of them, with two index variables. I also have a problem with updateControls. Any help would be greatly appreciated.

private void updateControls()
{
    pictureBox1.Image = resList[currentResIndex].Photo;
    lblName.Text = resList[currentResIndex].Title;
    lblCity.Text = resList[currentResIndex].City;
    lblPrice.Text = resList[currentResIndex].Price.ToString("C");

    pictureBox1.Image = comList[currentCommIndex].Photo;
    lblName.Text = comList[currentCommIndex].Title;
    lblCity.Text = comList[currentCommIndex].City;
    lblPrice.Text = comList[currentCommIndex].Price.ToString("C");
}

private void btnNext_Click(object sender, EventArgs e)
{
    if (cboType.SelectedItem.ToString() == "Residential") //if they chose residential then increment resIndex
开发者_开发技巧        currentResIndex++;
      updateControls();
    else
      currentCommIndex++;//or else commIndex
   updateControls();
}

  if (cboType.SelectedItem.ToString() == "Residential"
          && currentResIndex < resList.Count -1)    // add this condition
    currentResIndex++;

    updateControls();

You could just enforce the range in your btnNext_Click method:

private void btnNext_Click(object sender, EventArgs e)
{
    if (cboType.SelectedItem.ToString() == "Residential")//if they chose residential then increment resIndex
        currentResIndex++;
    else
        currentCommIndex++;//or else commIndex

    currentCommIndex = Math.Min(comList.Length-1, currentCommIndex);
    currentResIndex = Math.Min(resList.Length-1, currentResIndex);
    updateControls();
}

try
{
    if (cboType.SelectedItem.ToString() == "Residential") //if they chose residential then increment resIndex  
    {       
        currentResIndex++;       
    }
    else      
    {    
        currentCommIndex++;//or else commIndex 
    }
    updateControls();
}
catch (ArgumentOutOfRangeException ex)
{
    //Do the things you want when this exception occurs
}

But imho you shouldn't be using this. You should check whether or not the end of the List is reached.