Search Widget

Hi,
I've field that relate to each other. My question

1. How to make when user pick value in Main Code, the value in Type Code only display a value that relate to Main Code and
value in Sub Code only display a value that relate to Type Code? i'm using expression below but it all show all the value

<expression alias="Status Code" textsearchlabel="Search Code:" isvaluerequired="False">
<values>
<value prompt="Main Code" isvaluerequired="true" uniquevalsfromfield="Main_Code" >Main_Code = '[value]'</value>
<value prompt="Type Code" isvaluerequired="true" uniquevalsfromfield="Type_Code" operation="AND" >Type_Code = '[value]'</value>
<value prompt="Sub Code" isvaluerequired="true" uniquevalsfromfield="Sub_Code" operation="AND" >Sub_Code = '[value]'</value>
</values>
</expression>

2. How to make widget start searching when all value has been choose? I'm using expression above the widget start searching when i pick a first value.

Any help would be greatly appreciated.

Thank.

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