Insert text into the textbox of another application

Question

How do I, using C# or C++, insert text into the textbox of another application? I did this a long time ago and seemed to remember something about using the applications HWND

Answer 1

Instead of targeting a specific app you could just send keystrokes to the text field.

  private void button1_Click(object sender, EventArgs e)
    {
       System.Threading.Thread.Sleep(5000);
       SendKeys.Send(send_text);

    private void textBox1_TextChanged(object sender, EventArgs e)
    {
        send_text = textBox1.Text;            
    }