Rules are probably best described by using examples. This chapter contains numerous real world samples.

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Show/Hide Manager Approval

You have a flow and the first form has a Section for manager approval. The Section is hidden by default. Here is an example of a rule that makes the section visible in the second step of the flow which is a linked activity assigned to the manager role. 

if (form.load) {
  var an = _data.getParameter ("flow.activity.name");
  if (an === 'Manager'){
    ManagerApproval.visible = true;
  } else {
    ManagerApproval.visible = false;
  }
}

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/ Calculate Hospital Stay Duration 
if (A.value !== '' && D.value !== '') { 
    var da = A.value.split('-'); 
    var Ams = new Date(da[0],da[1],da[2]); 
    da = D.value.split('-'); 
    var Dms = new Date(da[0],da[1],da[2]);
 
    if (Ams > Dms) { 
        Days.value = 'Discharge date must be after Admission Date'; 
    } else { 
        Days.value = (Dms - Ams) / (1000*60*60*24) + ' days'; 
    } 
}

Duration (between Date/Time)

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Traveler1.visible = false;
Traveler2.visible = false;
Traveler3.visible = false;
Traveler1.required = false;
Traveler2.required = false;
Traveler3.required = false;

for (var i=0; i < NumTickets.value; i++) {
 if (i >= 0) {
  Traveler1.visible = true;
  Traveler1.required = true;
 }
 if (i >= 1) {
  Traveler2.visible = true;
  Traveler2.required = true;
 }
 if (i >= 2) {
  Traveler3.visible = true;
  Traveler3.required = true;
 }
}

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Tables

Tables are identical to repeat controls when referenced in business rules. Tables are a grid layout of repeating items. All the rule examples in this chapter that discuss repeats apply also to tables. The one important note is that you cannot explicitly name the repeat control inside your table. The repeat control inside a table is automatically named as <TableName>Repeat. For example a table named Expense automatically has a repeat named ExpenseRepeat. The rule ExpenseRepeat.itemAdded and ExpenseRepeat.itemIndex references an item added to your table and that item's index respectively.

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Notice the TableItem deletable property is set to false when a capital Y is entered in the first column. This will remove the minus icon for that row of the table. The for loop cycles through the table rows until the Max# property is reached. 

Clearing Values in a Table

This rule clears the values from all rows in a table. Notice the For loop that iterates over all the rows. Inside the loop a null value is assigned to all the columns in the table row.

 for (var i = 0; i < Col0.value.length; i++) { 
    Col0[i].value = null;
    Col1[i].value = null;
    Col2[i].value = null;
  } 

You cannot clear an entire table from a rule.

form.load

Rules can be used to initialize field values. This is a very useful feature and is often used to dynamically populate dropdown options from a database. Rules using form.load are triggered when a form first loads and when a workflow is loaded from a task list.

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