Applicable Versions: All

Required values occur when conditions are created against the subject or query, that have been designated as Required Values in either the subject or query wizard. In normal operation, DataPA prompts the user for values to satisfy these required values in the query wizard at runtime. However, when embedding DataPA, you may often wish the application to set these required values, for instance if you are designing an invoice viewer, you may want the Application to select the Invoice to be displayed.

The RequiredFields collection has one property and one method that allow us to retrieve information about the required fields. First is the Count property that retrieves the number of required values for the query. The following VB code example shows how to display a message showing the number of required fields:

To retrieve individual required fields, the required fields property has an Item method. The Item method returns a DataPA.Fields object. The table below summarised the properties of the fields object: 

The following code shows how to display a message showing the name of each required field for a query:

The SetRequiredField method on the query object allows you to programmatically set a value of a required field. If a required field value is set programmatically BEFORE you call the RunQuery method, the query wizard will not prompt the user for that value. The SetRequiredField method requires two parameters. The first is the field name, a character expression that resolves to a field name. The field name should match exactly the name value returned from the Field object. The second is the value, an expression that represents the value you wish to assign to the field. The value should be the data type specified by the DataType property of the Field object. The following code extract sets the value of the custnum field to 1 before running the query:

Required values can sometimes be optional. If the person who created the query did not check the mandatory option when creating the required field, the user is given the option to skip the required field. You can programmatically skip a required field using the SetSkipField method. If the SetSkipField method is called on a non-mandatory required field BEFORE the RunQuery method is called, the required field will not be prompted for by the run query wizard. The SetSkipField method requires a single parameter, FieldName, a character expression that resolves to a field name. The field name should match exactly the name value returned from the Field object. The following code extract sets the custnum field to skip before running the query: 

The following code extract shows how we can put all this together to prompt for any parameters from any query from our VB application before we run the query: