Modifying the Filter Pattern with Generic Lambda Expressions

Pipeline & Filter ( ), , , - ( ) . , WPF- . .

Pipeline & Filter

. , (generic) -. . ​​ :

ConditionAggregator



- , Condition<T>



. Filter<T>



ConditionAggregator



Condition<T>



(condition) . apply () Filter<T>



, check () ICondition<T>



. ConditionAggregator<T>



OnFilterChanged



. , . Filter .

MVVM . (View Model) MVVM - . -, . ConditionAggregator<T>



OnFilterChanged



, apply. .

Employee



. Generic



T



Filter



Employee



. EmployeeList



. .

public EmployeeList(IEmployeesRepository repository, ConditionAggregator<employee> conditionAggregator)
        {
            this.repository = repository;
            this.filters = new ConcreteFilter<employee>(conditionAggregator);
            conditionAggregator.OnFilterChanged += this.FilterList;
            _ = initAsync();
        }
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

FilterList



OnFilterChanged



, .

private void FilterList()
{
    this.Employees = this.filters.Apply(this.employeesFullList);
}
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

EmployeesViewModel



. EmployeeTypeselected



, ConditionAggregator



. - -, .

public EmployeesViewModel(IEmployeesRepository repository)
        {
            this.repository = repository;
            Condition<employee> filterEmployee = new Condition<employee>((e) => e.employeeCode == this.EmployeeTypeSelected);
            this.conditionAggregator = new ConditionAggregator<employee>(new List<condition<employee>> { filterEmployee });
            this.EmployeeList = new EmployeeList(repository, this.conditionAggregator);            
        }  
</condition<employee></employee></employee></employee>
      
      

        
        
        
      

    
        
        
        
      
      

        
        
        
      

    
    

-. , ConditionAggregator



. , , .

WPF.Demo.DataFilter



- WPF. . WPF.Demo.DataFilter.ViewModels



, . WPF.Demo.DataFilter.Common



Pipeline & Filter. WPF.Demo.DataFilter.DAL



json- .

:

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