xml for accessing the repeater control row values in infopath form

I have the web service, which has method State() that returning the List. where i want to design the infopath form that having the repeating table. in repeating table one of column should have the drop down list.

I want to populate this List in the drop down list (states). Each selected instance in the dropdown must be unique means when i would select state A for row 1 then in other row there must be validation that should not select the state A again.

in short开发者_如何学JAVA avoid the duplicate selection.

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Include a section with a validation message under each dropdown. Select the section Properties > Display > Conditional formatting.

Set the condition as dropdown2_field is equal to dropdown1_field. (Need to add similar multiple conditions for 3rd,4th successive dropdown boxes.)

and select Hide this control check box.

If the user selects the same state in dropdown2 the validation message is shown.