How to Create and Use the New Data Screen in LightSwitch Beta 2

Hello Jagan: I notice in the many examples, string sizes are left at default 255. Is it not better to decalre the max size example Name as 40 etc instead of leaving at 255 MAny thanks, Bhuven

Hello Jagan: I have a new data screen with header and detail records for orders. I create the header details as you example above and the detail records are in a row in a datagrid where lightswitch automatically creates commands as well. I donot want to use default entry screen for child records becuase I cannot make changes in the code behind. I create a defgault screen and change the code to access the default screen instead of lightswitch default. I am able to open screen but screen is in read only mode. Can you kindly assist with suggestion of what I am missing or doing wrong. Thank you in advance Bhuven