Question

I have a ListView with 2 columns. For example’s sake, we’ll say it looks like this:

ColA    | ColB  
-----------------
001     |  
002     |  
003     |  
004     |  
005     |  

I have a text file that contains the following lines:

001  
002  
004  
005  
008  

I’m trying to read through the file line by line, and if the number matches a number in ColumnA, I want to add it to ColumnB. That works fine (see my example below). However, I’d also like to add any non-matches as a new ListViewItem. I can’t figure that part out. Here’s what I have so far:

foreach (string textfileitem in TheTextFile)
{
    foreach (ListViewItem item in ListView1.Items)
    {
        var existingitem = item.SubItems[0];

        if (existingitem.Text == textfileitem)
        {
            item.SubItems[1].Text = textfileitem;
        }
    }
}

I’m not sure how to handle any non-matches and add them to the ListView. the end result would look like this:

ColumnA | ColumnB
----------------- 
001     | 001
002     | 002
003     | 
004     | 004
005     | 005
-       | 008

As always, your help is appreciated!

Answer 1

Run through your columnA, create a dictionary of <String,YourDataSourceItem>. Run through your file – test match using TryGetValue. If found, set columnB. If not, create a new item.