Dataprovider question

[shaunthomson1]

Hi

Just a small area of dataProvider code I am 5% unsure of.

When you populate a provider with an object, eg...

myData = JSON.parse(event.target.data);// add JSON to object

listDP = new DataProvider(myData);// add object to dataProvider

data_grid.dataProvider = listDP;//set datagrid's dataProvider

...when you are making edits to the data, do you edit myData, and then to update the dataProvider...

listDP = new DataProvider(myData);// update dataProvider

...or do you somehow edit listDP directly?

Another way to ask...

...if the above was in an editable datagrid, when you make an edit, does Flash update myData, then do listDP = new DataProvider(myData); , or does it directly edit listDP?

Thanks guys

[kglad · Accepted solution]

the dataProvider property of your datagrid will update so you would use:

listDP=data_grid.dataProvidier

to update listDP (which does not save json data anywhere).

[shaunthomson1]

Thanks kGlad

What if I'm not editing in the datagrid, but programatically adding data to it (from an external source)...

Example set up:

myData = JSON.parse(event.target.data);// add JSON to object

listDP = new DataProvider(myData);// add object to dataProvider

data_grid.dataProvider = listDP;//set datagrid's dataProvider

...and then I get some external data that needs to be added, do I add it to myData, or listDP? Currently I'm adding it to myData, then re-adding the line listDP = new DataProvider(myData); to update the datagrid.  Should I just be adding the data directly to listDP, and not myData?

[kglad]

you could do that, you could add data directly to listDP and you could add the data directly to data_grid.

i would use one of the latter two because i don't like creating new objects unless necessary.  you're not creating a potential memory problem with that because you use the same variable (listDP) but you will be adding additional (over the latter two methods) work for garbage collection.  but i don't foresee a performance problem creating new listDP objects unless you're doing that frequently.

[shaunthomson1]

I'm still confused mate.

myData = JSON.parse(event.target.data);// add JSON to myData array

listDP = new DataProvider(myData);// add array to dataProvider

data_grid.dataProvider = listDP;//set datagrid's dataProvider

Now when I try to access the dataProvider like...

trace(listDP[0].keyName);

...I get 'Property 0 not found on fl.data.DataProvider'

If I populated listDP with an array, and want to directly edit listDP, why does listDP[0] throw an error? Isn't the dataProvider an array?

[kglad]

a dataprovider is not an array.  it doesn't have array methods.  even if you used an array to define a dataprovider (which you did not), you can't use array methods.

use the dataprovider methods like getItemAt:

trace(listDP.getItemAt(0).keyName)

[shaunthomson1]

That just opened up a whole world for me. Thanks kGlad!!!

[kglad]

you're welcome.

p.s.  use the adobe help files.  the as3 class reference file contains a wealth of information.