I'm doing a small application using asp & C#. I'm having three text boxes. I want the result in the third text box when I changed from second text box to third.
For example: Let A= 10 , B=20 when I changed the tab from the textbox2 automatically print the result in the third box.
Please help me.

Thanks for helping me.
Warm Regards

Use the 'Leave' Event Handler for the second textbox.
Write in the code for whatever you want to display, in this event handler.

Consider using TextBox.Validating and/or TextBox.Validated methods to update other control's text. These are called before the TextBox.Leave and/or TextBox.Focus events are fired. The problems with the latter events is that there is not control over which will get fired first, which may not be an issue for you right now, but you will run into it one day if you haven't already.

The Validating event allows you to validate data and abort leaving the control if the data does not meet your criteria.

The Validated event occurs after validation above, indicating the TextBox.Text has passed whatever validation that may have been needed.