winform-linq.cs

// this is Form
var textBoxes = this.Controls
    .OfType<TextBox>()
    .Where(t => t.Name.StartsWith("textBox"))
    .OrderBy(t => Int32.Parse(t.Name.Substring("textBox".Length)))
    .ToList();
foreach (var _ in textBoxes.Select((t, i) => new { t, i, }))
{
    _.t.Text = "This is TextBox #" + _.i + "!";
}