QueryParameter

The QueryParameter is used in conjunction with Query object and QueryParametersView control. When a query requires some parameters in 'where' clause to be entered via user interface (QueryParametersView), we will use QueryParameter instead of where clause value. When QueryParametersView is initialized with such a query, it will show matching editors to fill in those values. See example below.

Constructor:

• constructor( name: string | Field, value?: any, values?: AttributeValue[] | ()=> AttributeValue[] )
  Creates a new QueryParameter instance.
• name: string | Field
  Defines the label shown in the QueryParametersView. It can be a text or a field object like Contract.amount.
• value: any
  Will be the initial value for the specified field shown in control QueryParametersView.
• value: AttributeValue[] | ()=> AttributeValue[]
  Used to limit possible values selection. It is an array of AttributeValue objects or a getter func returning an array of AttributeValue objects.

Example

this.queryMask = new QueryParametersView(this);
this.queryMask.source = await Contract.  
where(Contract.amount,   
      WhereOperator.Equal,   
      new QueryParameter(Contract.amount, 100000)).and  
where(Contract.party,   
      WhereOperator.equal,   
      new QueryParameter('Party name', '')).  
where(Contract.status, WhereOperator.equal, 'open').   
selectAsync();