Search code examples
c#linqmvvmcollectionview

Store math operator in variable

I am creating an application in C# MVVM. I have a simple question. Is there any possibility to store math operator in variable? I have a code like that:

public ICollectionView FilteredCollection
            {
                get
                {
                    return filteredCollection;
                }
                set
                {
                    filteredCollection = value;
                    OnPropertyChanged("FilteredCollection");
                }
            }



 FilteredCollection.Filter = x => (
                    (string.IsNullOrEmpty(DynamicSearchEmployeeName) || ((Employee)x).EmployeeName.Contains(DynamicSearchEmployeeName))
                    && (DynamicSearchEmployeeID == null || ((Employee)x).EmployeeID == DynamicSearchEmployeeID)
                    && (string.IsNullOrEmpty(DynamicSearchEmployeeSalary) || ((Employee)x).EmployeeSalary == Convert.ToInt32(DynamicSearchEmployeeSalary))
                    && (string.IsNullOrEmpty(DynamicSearchEmployeeDesigner) || ((Employee)x).EmployeeName.Contains(DynamicSearchEmployeeDesigner))
                    && (string.IsNullOrEmpty(DynamicSearchEmployeeEmailID) || ((Employee)x).EmployeeName.Contains(DynamicSearchEmployeeEmailID))
                    );

What I want to achieve: In fourth line (DynamicSearchEmployeeSalary) math operator should be depended on following conditions:

if (IsPressedEqual == true)
VARIABLE = "=="
if (IsPressedLess == true)
VARIABLE = "<"
if (IsPressedGreater == true)
VARIABLE = ">"
if (IsPressedLess == true && IsPressedEqual == true)
VARIABLE = "<="
if (IsPressedGreater == true && IsPressedEqual == true)
VARIABLE = ">="

Scenario:

For example I put a value like 10000 in textbox, then click on button with "=" operator. As a result I want to receive Employees with Salary equals than 10000. Then I click on ">". And I have Employees with Salary greater and equals 10000.

enter image description here

 FilteredCollection.Filter = x => (
                        (string.IsNullOrEmpty(DynamicSearchEmployeeName) || ((Employee)x).EmployeeName.Contains(DynamicSearchEmployeeName))
                        && (DynamicSearchEmployeeID == null || ((Employee)x).EmployeeID == DynamicSearchEmployeeID)
                        && (string.IsNullOrEmpty(DynamicSearchEmployeeSalary) || ((Employee)x).EmployeeSalary VARIABLE Convert.ToInt32(DynamicSearchEmployeeSalary))
                        && (string.IsNullOrEmpty(DynamicSearchEmployeeDesigner) || ((Employee)x).EmployeeName.Contains(DynamicSearchEmployeeDesigner))
                        && (string.IsNullOrEmpty(DynamicSearchEmployeeEmailID) || ((Employee)x).EmployeeName.Contains(DynamicSearchEmployeeEmailID))
Solution

  • I've made a simple Rule Based Engine ... I think it will help you in your issue ...

    please find it as a nuget package here: https://www.nuget.org/packages/IbnSherien.RuleBasedEngine/

    you can create a rule like this:

    var rule = RuleEngine.CreateRule<Employee>()
                     .If<Employee>(e => e.EmployeeSalary).GreaterThan(DynamicSearchEmployeeSalary)
                     .Validate();

FilteredCollection.Filter = x => (
                    (string.IsNullOrEmpty(DynamicSearchEmployeeName) || ((Employee)x).EmployeeName.Contains(DynamicSearchEmployeeName))
                    && (DynamicSearchEmployeeID == null || ((Employee)x).EmployeeID == DynamicSearchEmployeeID)
                    && (string.IsNullOrEmpty(DynamicSearchEmployeeSalary) || rule.Match((Employee)x).IsMatch)
                    && (string.IsNullOrEmpty(DynamicSearchEmployeeDesigner) || ((Employee)x).EmployeeName.Contains(DynamicSearchEmployeeDesigner))
                    && (string.IsNullOrEmpty(DynamicSearchEmployeeEmailID) || ((Employee)x).EmployeeName.Contains(DynamicSearchEmployeeEmailID))

    feel free to add any comments or contribute to the package