C＃：替换Listview中的空白项目文本？

Question

How would I go about about replacing the text of blank items in column 5 of my listView with the word "No"?

I tried this but it threw an InvalidArgument=Value of '4' is not valid for 'index'. error:

 foreach (ListViewItem i in listView1.Items)
 {
     if (i.SubItems[4].Text == " ")
     {
         i.SubItems[4].Text = i.SubItems[4].Text.Replace(" ", "No");
     }
 }

Answer 1

If I were you, I'd Use the debugger to figure out what's actually going on.

You can check and see what's actually in i.SubItems , and make sure it's actually what you think it is.

The only possible thing i can think of is maybe you made a typo somewhere or that i.SubItems[4] actually just isn't valid.

maybe you're iterating through some of your list items, but not all of your list items have 5 columns, or maybe some are empty.

Answer 2

The code provided above will get all items within ListView1.Items and check if the sub-item of index 4 and its property Text is equal to   which may result in the described error if the index exceeds the array limit. You may avoid this by making sure that this item is not Nothing .

Example

foreach (ListViewItem i in listView1.Items) //Get all items in listView1.Items
{
   if (i.SubItems.Count > 3) //Continue if i.SubItems.Count is more than 3 (The array contains i.SubItems[3] which refers to an item within the 4th column (i.SubItems.Count is not an array. Therefore, it'll start with 1 instead of 0))
   {
       if (i.SubItems[3].Text == " ") //Continue if i.SubItems[3].Text is equal to  
       {
            i.SubItems[3].Text = i.SubItems[3].Text.Replace(" ", "No"); //Replace   with No
       }
   }
}

Notice : Arrays are zero-indexed which means that they start with 0 instead of 1.
Notice : If you only have 4 columns, i.SubItems.Count would be 4 and not 3 because it's a normal int considering that all columns are filled .

Thanks,
I hope you find this helpful :)

Answer 3

Once you get that first error figured out, your logic for replacing the text might work better like this:

if (i.SubItems != null && string.IsNullOrEmpty(i.SubItems[4].Text))
{
    i.SubItems[4].Text = "No";
}