Hiding Row in DataGridView Very Slow

Question

I have a DataGridView in a Winforms app that has about 1000 rows (unbound) and 50 columns. Hiding a column takes a full 2 seconds. When I want to hide about half the rows, this becomes a problem.

    private void ShowRows(string match)
    {
        this.SuspendLayout();
        foreach (DataGridViewRow row in uxMainList.Rows)
        {
            if (match == row.Cells["thisColumn"].Value.ToString()))
            { row.Visible = false; }
            else
            { row.Visible = true; }
        }
        this.ResumeLayout();
    }

I did some testing by adding by addingConsole.WriteLine(DateTime.Now)around the actions, androw.Visible = falseis definitely the slow bit. Am I missing something obvious, like setting IsReallySlow = false? Or do I have to go ahead and enable Virtual Mode and code up the necessary events?

Answer 1

It looks to me like you should be using row filters instead.

Try using a DataView as your binding source and use DataView.RowFilter to hide rows or show rows of your choosing.

DataGridView myGridView = new DataGridView();
DataView myDataView = myTable.DefaultView;
myGridView.DataSource = myDataView; // DataView that allows row filtering

myDataView.RowFilter = string.Format("thisColumn <> '{0}'",match);  // this will hide all rows where "thisColumn" = match