How to programmatically press the button?

If you need to press a button in another application, then there are options:

• emulate regular and hot keystrokes using SendKeys calls;
• use P / Invoke to find handles of buttons and send messages to SendMessage;
• use the UI Automation API ( example ).

button1.PerformClick();

Just do not do it in any way in the event of pressing the button, otherwise there will be an endless recursion of click calls!

 private void button1_Click(object sender, EventArgs e) { MessageBox.Show("Мир."); } private void button2_Click(object sender, EventArgs e) { button1.PerformClick(); }