find string in DataGridView

Question

I'm using a foreach loop to populate each row in a DataGridView with a string. I need to search the DataGridView to make sure that I don't add a string that is already there. What is the best way to do this?

Here is my code so far:

foreach (String file in openFileDialog.FileNames)
    {                                    
        // todo: make sure file string does not already exist in DataGridView
        dataGridView1.Rows.Add();
        dataGridView1.Rows[i].Cells[1].Value = file;
        i++;
    }

Please note that there may already be file names in the DataGridView from a previous run of the code.

Answer 1

It is a good idea not to use a DataGridView as a datastore. It is a Control for displaying stuff.

It is better to bind it to some backing store and do your operations on that:

var table = new HashSet<string>();

table.Add("aa");
table.Add("bb");
table.Add("aa");

dataGridView1.AutoGenerateColumns = true;
dataGridView1.DataSource = table.ToList();

And when new a new batch of files comes in, add them to the HashSet and simply re-bind the Grid.

Answer 2

foreach (String file in openFileDialog.FileNames.Distinct()) 
    {                                     
        // todo: make sure file string does not already exist in DataGridView 
        dataGridView1.Rows.Add(); 
        dataGridView1.Rows[i].Cells[1].Value = file; 
        i++; 
    } 

(Assuming C# 3.0 and LINQ extensions for IEnumerable<>)