DxListBox<TData, TValue>.GetFilterCriteria() Method

Returns the filter criteria applied to List Box data.

Namespace: DevExpress.Blazor

Assembly: DevExpress.Blazor.v24.1.dll

NuGet Package: DevExpress.Blazor

Declaration

public CriteriaOperator GetFilterCriteria()

Returns

Type	Description
CriteriaOperator	An object that specifies the filter expression.

Remarks

You can use the SetFilterCriteria(CriteriaOperator) method to apply filter criteria to List Box data. To get the applied filter criteria, use the GetFilterCriteria method.

Razor

<DxToolbar ItemClick="@OnItemClick">
    <Items>
        <DxToolbarItem Name="_setFilterCriteria" Text="Set Filter Criteria" Tooltip="Set Filter Criteria" />
        <DxToolbarItem Name="_clearFilterCriteria" Text="Clear Filter Criteria" Tooltip="Clear Filter Criteria" />
    </Items>
</DxToolbar>
<br/>
<DxListBox @ref="@_listBox" TData=Person TValue=Person Data="Staff.DataSource"
            ShowCheckboxes="true"
            SelectionMode="@ListBoxSelectionMode.Multiple">
    <Columns>
        <DxListEditorColumn FieldName="FirstName"></DxListEditorColumn>
        <DxListEditorColumn FieldName="LastName"></DxListEditorColumn>
        <DxListEditorColumn FieldName="Department"></DxListEditorColumn>
        <DxListEditorColumn FieldName="Salary"></DxListEditorColumn>
    </Columns>
</DxListBox>
<p class="cw-480 mt-3">
    Filter Criteria: <b>@_listBox?.GetFilterCriteria().ToString()</b>
</p>

@code {
    IListBox<Person, Person> _listBox;
    void OnItemClick(ToolbarItemClickEventArgs e) {
        switch(e.ItemName) {
            case "_setFilterCriteria":
                _listBox.SetFilterCriteria(new BinaryOperator(nameof(Person.Salary), 2000, BinaryOperatorType.Greater));
                break;
            case "_clearFilterCriteria":
                _listBox.ClearFilter();
                break;
        }
    }
}

StaffData

namespace StaffData {
    public static class Staff {
        private static readonly Lazy<List<Person>> dataSource = new Lazy<List<Person>>(() =>
        {
            Random rnd = new Random();
            var dataSource = new List<Person>() {
                new Person() { Id = 0 , FirstName = "John John", LastName = "Heart", Department = Department.Electronics, Salary = GetRandomSalary(rnd)  },
                new Person() { Id = 1 , FirstName = "Samantha", LastName = "Bright", Department = Department.Motors, Salary = GetRandomSalary(rnd)  },
                new Person() { Id = 2 , FirstName = "Arthur", LastName = "Miller", Department = Department.Software, Salary = GetRandomSalary(rnd)   },
                new Person() { Id = 3 , FirstName = "Robert", LastName = "Reagan", Department = Department.Electronics, Salary = GetRandomSalary(rnd)  },
                new Person() { Id = 4 , FirstName = "Greta", LastName = "Sims", Department = Department.Motors, Salary = GetRandomSalary(rnd)  },
                new Person() { Id = 5 , FirstName = "Brett", LastName = "Wade", Department = Department.Software, Salary = GetRandomSalary(rnd)   },
                new Person() { Id = 6 , FirstName = "Sandra", LastName = "Johnson", Department = Department.Electronics, Salary = GetRandomSalary(rnd)  },
                new Person() { Id = 7 , FirstName = "Edward", LastName = "+Holmes", Department = Department.Motors, Salary = GetRandomSalary(rnd)  },
                new Person() { Id = 8 , FirstName = "Barbara", LastName = "Banks", Department = Department.Software, Salary = GetRandomSalary(rnd)  },
                new Person() { Id = 9 , FirstName = "Kevin", LastName = "Carter", Department = Department.Electronics, Salary = GetRandomSalary(rnd) },
                new Person() { Id = 10, FirstName = "Cynthia", LastName = "Stanwick", Department = Department.Motors, Salary = GetRandomSalary(rnd)   },
                new Person() { Id = 11, FirstName = "Sam", LastName = "Hill", Department = Department.Electronics, Salary = GetRandomSalary(rnd)   },
            };
            return dataSource;
        });
        public static List<Person> DataSource { get { return dataSource.Value; } }
    }

    public class Person {
        public int Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public Department Department { get; set; }
        public string Text => $"{FirstName} {LastName} ({Department} Dept.)";
        public decimal Salary { get; set; }
        public DateTime BirthDate { get; set; }
        public override bool Equals(object obj) {
            if (obj is Person typedObj) {
                return (this.Id == typedObj.Id) && (this.FirstName == typedObj.FirstName) && (this.LastName == typedObj.LastName)
                && (this.Department == typedObj.Department);
            }
            return base.Equals(obj);
        }
    }

    static decimal GetRandomSalary(Random rnd) {
        return rnd.Next(1000, 3000);
    }

    public enum Department { Motors, Electronics, Software }
}

Implements

GetFilterCriteria()