Data entry mobile app like calculator

Hello! I need a mobile app for windows mobile. It must be in C#. Must run on windows phone. Its just like very simple data entry app. User will open the app, there will be two button. Start analysis and Show analysis. As user click on Start then one screen will come like calculator, there will be date and time at the top of the app and text box and then as user enter the digits and click on E button. The data will save in text file. In the start text file will be created automatically but if want to set the name manually then we can do it as well. So the informatoin will save in text file and finish. User can update the digits as well but not time, user can delete the file as well. For more information, see the attached document with screen. Regards