C# and touchscreen

Question

Hello I am working on an application that uses touch screens. I am going to have to provide an on screen number pad to allow user input. The problem is that I have multiple data input fields that the user will have to select. So the number pad will be used for multiple input controls. How do I create the number pad so that the selected control does not lose focus and the user can enter a multi-character string into the control? Hope I'm being clear - thanks for any help.

Scott Lysle · Answer

Ah well you will still need some event that you can use to define which box gets the inputs from the keypad. Maybe the thing to do would be to have private member variable (a short or an int) and whenever your target gets the focus set that int value to something used to represent that textbox. When you read the button hits you can direct the text to the last textbox that had the focus (by checking the value of the private variable with a switch statement). Since you'd only update this private variable after one of the targets received the focus there should not be any conflict after the box loses focus (as when you are using the buttons).

dinger · Answer

Thanks for the response. I thought of doing something like that but I don't think that would be ideal in my situation. As I said before I have multiple text boxes that will need to be keyed to so there will still be the issue of which one to write the finished string to. Also one of the objects is a combo box which I would like to have autocomplete so the user might not have to enter the full string. For instance if the user type 101 I would like it to autofill the rest of the value - 101 - myCompany. Hope this makes sense.

Scott Lysle · Answer

If you have virtual keypad you would normally have a scratchpad above it showing the numbers keyed in by the user; just like a handheld calculator. It does matter if the scratchpad has focus or not since the button hits are going to be sent to the scratchpad until the total value is collected sent to where it needs to go. There is going to be some event that will be fired and used to send the content of the scratchpad to its final destination. For example if you have a standard numeric keypad (0-9 dash and decimal point) and you are using the keypad to set the radio frequency for one of two radios you might key 121.500 into the scratchpad and then press a button that will send that to comm 1 the first radio and then clear the scratchpad. You might then key 243.000 into the scratchpad and select the comm2 button to send that value to the second radio. As far the button hits goes you'd just do something like: scratchPad.Text += 9 for button 9. My comm 1 button might send the scratchpad to some function like: Comm1.Freq.Set(scratchPad.Text.ToString().Trim()); followed by scratchPad.Text = string.Empty;