HTML Client RIA Services implementation question

Question

I would like to use a custom RIA service query as the data source for a browse screen.  The RIA service query will have many (50+) parameters.  The underlying table has 50+ columns so I want to pass in all of the parameters to the RIA service,
execute the query, and return a custom entity that contains only the 5 or 6 columns I want to display as a summary in the browse screen table.  When a user selects a row on the table, they will have the ability to edit the record.  They will also
have the ability to add a new record.  However, in both the add and edit scenarios, I want them to be able to add/update the underlying table, not the RIA entity, which obviously does not contain all of the columns.  The RIA service entity will contain
the Id column of the underlying table so I plan to open the add new and details screens (built on the underlying table) with a custom button passing in the Id value.  Has anyone tried this approach?  Are their any drawbacks? 

Answer 1

Hey Hessc,
I've not actually done this, but the idea came up whilst replying to your post above. I'm convinced it can be done and will work well and will be relatively clean, so here are the steps as I see it:
Create screen properties for each of the 50 params that you would require and create corresponding UI controls as required
In the screen _created event instantiate a new Javascript object that has properties for each of the above 50 params. Assign this object to myapp.MyScreen so that you can access it from any other function in the screen (e.g. myapp.MyScreen.QueryParams =
new {...})
Declare a string screen property that will represent the single RIA query parameter (e.g. RiaParameter)
In the screen _created event hook up change listeners to each of the 50 screen properties and inside each of those listeners you assign the value from the changed screen property to the equivalent myapp.MyScreen.QueryParams property to keep the QueryParams
properties in sync and then serialize the latest version of the myapp.MyScreen.QueryParams to a JSON string and assign it to the screen.RIaParameter property which will cause the query to be refreshed and the JSON parameter to be passed to the RIA query
method in the backend
To add a change handler to each of the 50 screen properties to a) update the javascript object and b) to update the RIA query parameter to refresh the query:
screen.addChangeListener("Parameter1", function (value) {
// assign the screen property value to the javascript object property
myapp.MyScreen.QueryParams.Parameter1 = value;
// serialize javascript object to JSON
var jsonStr = JSON.stringify(myapp.MyScreen.QueryParams);
// update query parameter with JSON string
screen.RiaParameter = jsonStr;
On the C# side you can deserialize the passed JSON string parameter using something like:
http://stackoverflow.com/questions/4535840/deserialize-json-object-into-dynamic-object-using-json-net
Note: To ensure that your query is not refreshed 50 x times when the screen initially loads, you may want put some code in place that will only update the screen.RiaParameter once the screen is totally initialized... perhaps something like a boolean IsInitialized
flag...
Hope this helps.
Regards, Xander. My Blog