Slow performance in populating DataGridView with large data

Make sure u don't auto-size columns, it improves performance.

i.e. don't do this:

Datagridview.Columns[I].AutoSizeMode = DataGridViewAutoSizeColumnMode.xxxxx;

If you have a huge amount of rows, like 10,000 and more, to avoid performance leaks - do the following before data binding:

dataGridView1.RowHeadersWidthSizeMode = DataGridViewRowHeadersWidthSizeMode.EnableResizing; 
// or even better, use .DisableResizing. Most time consuming enum is DataGridViewRowHeadersWidthSizeMode.AutoSizeToAllHeaders

// set it to false if not needed
dataGridView1.RowHeadersVisible = false;

After the data is bound, you may re-enable it.

Generally turning auto-sizing off and double buffering help to speed up DataGridView population. Check whether the DGV double buffering is turned on properly:

if (!System.Windows.Forms.SystemInformation.TerminalServerSession)
{
  Type dgvType = dataGridView1.GetType();
  PropertyInfo pi = dgvType.GetProperty("DoubleBuffered",
    BindingFlags.Instance | BindingFlags.NonPublic);
  pi.SetValue(dataGridView1, value, null);
}

Disabling the redrawing with the WinAPI WM_SETREDRAW message also helps:

// *** API Declarations ***
[DllImport("user32.dll")]
private static extern int SendMessage(IntPtr hWnd, Int32 wMsg, bool wParam, Int32 lParam);
private const int WM_SETREDRAW = 11;

// *** DataGridView population ***
SendMessage(dataGridView1.Handle, WM_SETREDRAW, false, 0);
// Add rows to DGV here
SendMessage(dataGridView1.Handle, WM_SETREDRAW, true, 0);
dataGridView1.Refresh();

If you do not need 2-way data-binding or some features provided by BindingSource (filtering, etc.), you may consider adding rows at one go with the DataGridView.Rows.AddRange() method.

The link to the source article with the sample: http://10tec.com/articles/why-datagridview-slow.aspx