Cannot find a defined variable

I'm really new to Dynamix AX 2009.

I was browsing the demo image from Microsoft to better understand how the application works. I checked a random method called updateRFIDTagging() in the form SalesQuotationTable

Now this last bl开发者_StackOverflow中文版ock of code really confuse me:

salesQuotationLine_ds.object(fieldnum(SalesQuotationLine, ItemTagging)).skip          (!itemTagging);
salesQuotationLine_ds.object(fieldnum(SalesQuotationLine, CaseTagging)).allowEdit     ( caseTagging);
salesQuotationLine_ds.object(fieldnum(SalesQuotationLine, CaseTagging)).skip          (!caseTagging);
salesQuotationLine_ds.object(fieldnum(SalesQuotationLine, PalletTagging)).allowEdit   ( palletTagging);
salesQuotationLine_ds.object(fieldnum(SalesQuotationLine, PalletTagging)).skip  

I cannot find where the "salesQuotationLine_ds" is declared (and the code compile fine!). So my questions are:

1. Where is it declared?
2. Is there a shortcut/menu item that I can use to go to the declaration?

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_ds is a way to access the Form data source.

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The variable x_ds is automatically defined for each x data source. There is a another auto declared variable x_q which is the data source query.

Reference: http://msdn.microsoft.com/en-us/library/aa629025.aspx (in the Remarks section).

For an easy (but not bullet proof) way to go to the declaration of a variable:

http://www.axaptapedia.com/AxGoToDeclaration