How to pass parameters from subgrids to JavaScript

In this post I will show you how to pass parameters regarding a grid or subgrid to a JavaScript function by clicking a custom button on the ribbon menu.
A common requirement is to pass poarameters to a JavaScript function called when clicking a Ribbon button.
To pass parameters regarding a grid or a subgrid we can use the "crmparameter" element of the RibbonDiffXml file.
The available parameters can be devided in three groups:

1. Selected items 
• SelectedControlSelectedItemCount: The number of selected items in a grid or subgrid.
• SelectedControlSelectedItemIds: A string array of GUID Id values for all selected items in a grid.
• SelectedControlSelectedItemReferences: An array of EntityReference objects that represent all the selected items in the grid
2. All items
• SelectedControlAllItemCount: The number of items in a grid or subgrid.
• SelectedControlAllItemIds: A string array of GUID Id values for all items in a grid.
• SelectedControlAllItemReferences: An array of EntityReference objects that represent all the items in the grid.
3.  Unselected items
• SelectedControlUnselectedItemCount: The number of unselected items in a grid or subgrid.
• SelectedControlUnselectedItemIds: A string array of GUID Id values for all unselected items in a grid.
• SelectedControlUnselectedItemReferences: An array of EntityReference objects that represent all the unselected items in the grid. 

The way you can pass these parameters by clicking a Ribbon button is shown below:

  <CommandDefinition Id="Mscrm.SubGrid.opportunity.Command">
            <EnableRules>
              <EnableRule Id="Mscrm.SubGrid.opportunity.EnableRule"></EnableRule>
            </EnableRules>
            <DisplayRules></DisplayRules>
            <Actions>
              <JavaScriptFunction Library="$webresource:functions.js" FunctionName="MyFunction" >
                <CrmParameter Value="SelectedControlSelectedItemIds" />
                <CrmParameter Value="SelectedControlSelectedItemCount" />
              </JavaScriptFunction>
            </Actions>
</CommandDefinition>

To access these parameters add them to your function definition like below:

function MyFunction(SelectedControlSelectedItemIds, SelectedControlSelectedItemCount) {
      for (i = 0; i < SelectedControlSelectedItemCount; i++) {
       }
}


So as you can see it is possible to access records displayed in a subgrid using supported code, so don't get tempted to use document.getElementById.  ;)

I hope this help.