Grid View for ASP.NET Web Forms - How to apply custom function filter criteria operators

This example demonstrates how to use a CriteriaPatchBase class descendant to apply a custom function criteria operator.

Custom function filter criteria operator

Overview

Assign a custom function operator to the grid's FilterExpression property. For the auto filter row, handle the grid's server-side ProcessColumnAutoFilter event as follows:

C#
protected void Grid_ProcessColumnAutoFilter(object sender, DevExpress.Web.ASPxGridViewAutoFilterEventArgs e) {  
    var grid = (ASPxGridView)sender;  
    if(e.Column.FieldName == SpecialFilterColumnFieldName && e.Kind == GridViewAutoFilterEventKind.CreateCriteria) {  
        grid.FilterExpression = UpdateGridFilterExpression(grid, e);  
        e.Criteria = null;  
    }  
}

Handle the grid's server-side AutoFilterCellEditorInitialize event to assign the custom criteria operator value to the filter editor.

C#
protected void Grid_AutoFilterCellEditorInitialize(object sender, ASPxGridViewEditorEventArgs e) {  
    var grid = (ASPxGridView)sender;  
    if(e.Column.FieldName == SpecialFilterColumnFieldName) {  
        var gridCriteria = CriteriaOperator.Parse(grid.FilterExpression);  
        e.Editor.Value = CriteriaVisitor.GetCustomFunctionOperatorValue(gridCriteria, e.Column.FieldName);  
    }  
}

Files to Review

CriteriaPatcherBase.cs (VB: CriteriaPatcherBase.vb)
CriteriaVisitor.cs (VB: CriteriaVisitor.vb)
MyCustomFunctionOperator.cs (VB: MyCustomFunctionOperator.vb)
Default.aspx (VB: Default.aspx)
Default.aspx.cs (VB: Default.aspx.vb)

Documentation

The base implementation of the IClientCriteriaVisitor interface for the CriteriaOperator expression patcher

Example Code

App_Code/CriteriaPatcherBase.cs(vb)

C#
VB.NET

C#
using DevExpress.Data.Filtering;

public class CriteriaPatcherBase : IClientCriteriaVisitor<CriteriaOperator> {
    protected CriteriaPatcherBase() { }

    protected CriteriaOperator AcceptOperator(CriteriaOperator theOperator) {
        if (IsNull(theOperator)) return null;
        return theOperator.Accept<CriteriaOperator>(this);
    }

    protected CriteriaOperatorCollection VisitOperands(CriteriaOperatorCollection operands) {
        bool isModified = false;
        CriteriaOperatorCollection result = new CriteriaOperatorCollection(operands.Count);
        foreach (CriteriaOperator operand in operands) {
            CriteriaOperator acceptedOperand = this.AcceptOperator(operand);
            result.Add(acceptedOperand);
            if (!object.ReferenceEquals(operand, acceptedOperand))
                isModified = true;
        }
        return isModified ? result : operands;
    }

    protected static bool IsNull(CriteriaOperator theOperator) {
        return object.ReferenceEquals(theOperator, null);
    }

    protected virtual CriteriaOperator VisitJoin(JoinOperand theOperand) {
        CriteriaOperator aggregatedExpression = this.AcceptOperator(theOperand.AggregatedExpression);
        CriteriaOperator condition = this.AcceptOperator(theOperand.Condition);
        if (object.ReferenceEquals(theOperand.AggregatedExpression, aggregatedExpression) &&
            object.ReferenceEquals(theOperand.Condition, condition))
            return theOperand;
        return new JoinOperand(theOperand.JoinTypeName, condition, theOperand.AggregateType, aggregatedExpression);
    }

    protected virtual CriteriaOperator VisitProperty(OperandProperty theOperand) {
        return theOperand;
    }

    protected virtual CriteriaOperator VisitAggregate(AggregateOperand theOperand) {
        CriteriaOperator aggregatedExpression = this.AcceptOperator(theOperand.AggregatedExpression);
        CriteriaOperator condition = this.AcceptOperator(theOperand.Condition);
        if (object.ReferenceEquals(theOperand.AggregatedExpression, aggregatedExpression) &&
            object.ReferenceEquals(theOperand.Condition, condition))
            return theOperand;
        return new AggregateOperand(theOperand.CollectionProperty, aggregatedExpression, theOperand.AggregateType, condition);
    }

    protected virtual CriteriaOperator VisitFunction(FunctionOperator theOperator) {
        CriteriaOperatorCollection operands = this.VisitOperands(theOperator.Operands);
        if (object.ReferenceEquals(theOperator.Operands, operands))
            return theOperator;
        return new FunctionOperator(theOperator.OperatorType, operands);
    }

    protected virtual CriteriaOperator VisitValue(OperandValue theOperand) {
        return theOperand;
    }

    protected virtual CriteriaOperator VisitGroup(GroupOperator theOperator) {
        CriteriaOperatorCollection operands = this.VisitOperands(theOperator.Operands);
        if (object.ReferenceEquals(theOperator.Operands, operands))
            return theOperator;
        return new GroupOperator(theOperator.OperatorType, operands);
    }

    protected virtual CriteriaOperator VisitIn(InOperator theOperator) {
        CriteriaOperator leftOperand = this.AcceptOperator(theOperator.LeftOperand);
        CriteriaOperatorCollection operands = this.VisitOperands(theOperator.Operands);
        if (object.ReferenceEquals(theOperator.LeftOperand, leftOperand) &&
            object.ReferenceEquals(theOperator.Operands, operands))
            return theOperator;
        return new InOperator(leftOperand, operands);
    }

    protected virtual CriteriaOperator VisitUnary(UnaryOperator theOperator) {
        CriteriaOperator operand = this.AcceptOperator(theOperator.Operand);
        if (object.ReferenceEquals(theOperator.Operand, operand))
            return theOperator;
        return new UnaryOperator(theOperator.OperatorType, operand);
    }

    protected virtual CriteriaOperator VisitBinary(BinaryOperator theOperator) {
        CriteriaOperator leftOperand = this.AcceptOperator(theOperator.LeftOperand);
        CriteriaOperator rightOperand = this.AcceptOperator(theOperator.RightOperand);
        if (object.ReferenceEquals(theOperator.LeftOperand, leftOperand) &&
            object.ReferenceEquals(theOperator.RightOperand, rightOperand))
            return theOperator;
        return new BinaryOperator(leftOperand, rightOperand, theOperator.OperatorType);
    }

    protected virtual CriteriaOperator VisitBetween(BetweenOperator theOperator) {
        CriteriaOperator beginExpression = this.AcceptOperator(theOperator.BeginExpression);
        CriteriaOperator endExpression = this.AcceptOperator(theOperator.EndExpression);
        CriteriaOperator testExpression = this.AcceptOperator(theOperator.TestExpression);
        if (object.ReferenceEquals(theOperator.BeginExpression, beginExpression) &&
            object.ReferenceEquals(theOperator.EndExpression, endExpression) &&
            object.ReferenceEquals(theOperator.TestExpression, testExpression))
            return theOperator;
        return new BetweenOperator(testExpression, beginExpression, endExpression);
    }

    #region IClientCriteriaVisitor
    CriteriaOperator IClientCriteriaVisitor<CriteriaOperator>.Visit(JoinOperand theOperand) {
        return this.VisitJoin(theOperand);
    }

    CriteriaOperator IClientCriteriaVisitor<CriteriaOperator>.Visit(OperandProperty theOperand) {
        return this.VisitProperty(theOperand);
    }

    CriteriaOperator IClientCriteriaVisitor<CriteriaOperator>.Visit(AggregateOperand theOperand) {
        return this.VisitAggregate(theOperand);
    }
    #endregion
    #region ICriteriaVisitor
    CriteriaOperator ICriteriaVisitor<CriteriaOperator>.Visit(FunctionOperator theOperator) {
        return this.VisitFunction(theOperator);
    }

    CriteriaOperator ICriteriaVisitor<CriteriaOperator>.Visit(OperandValue theOperand) {
        return this.VisitValue(theOperand);
    }

    CriteriaOperator ICriteriaVisitor<CriteriaOperator>.Visit(GroupOperator theOperator) {
        return this.VisitGroup(theOperator);
    }

    CriteriaOperator ICriteriaVisitor<CriteriaOperator>.Visit(InOperator theOperator) {
        return this.VisitIn(theOperator);
    }

    CriteriaOperator ICriteriaVisitor<CriteriaOperator>.Visit(UnaryOperator theOperator) {
        return this.VisitUnary(theOperator);
    }

    CriteriaOperator ICriteriaVisitor<CriteriaOperator>.Visit(BinaryOperator theOperator) {
        return this.VisitBinary(theOperator);
    }

    CriteriaOperator ICriteriaVisitor<CriteriaOperator>.Visit(BetweenOperator theOperator) {
        return this.VisitBetween(theOperator);
    }
    #endregion
}

Visual Basic
Imports DevExpress.Data.Filtering

Public Class CriteriaPatcherBase
    Implements IClientCriteriaVisitor(Of CriteriaOperator)

    Protected Sub New()
    End Sub

    Protected Function AcceptOperator(ByVal theOperator As CriteriaOperator) As CriteriaOperator
        If IsNull(theOperator) Then
            Return Nothing
        End If
        Return theOperator.Accept(Of CriteriaOperator)(Me)
    End Function

    Protected Function VisitOperands(ByVal operands As CriteriaOperatorCollection) As CriteriaOperatorCollection
        Dim isModified As Boolean = False
        Dim result As New CriteriaOperatorCollection(operands.Count)
        For Each operand As CriteriaOperator In operands
            Dim acceptedOperand As CriteriaOperator = Me.AcceptOperator(operand)
            result.Add(acceptedOperand)
            If Not Object.ReferenceEquals(operand, acceptedOperand) Then
                isModified = True
            End If
        Next operand
        Return If(isModified, result, operands)
    End Function

    Protected Shared Function IsNull(ByVal theOperator As CriteriaOperator) As Boolean
        Return Object.ReferenceEquals(theOperator, Nothing)
    End Function

    Protected Overridable Function VisitJoin(ByVal theOperand As JoinOperand) As CriteriaOperator
        Dim aggregatedExpression As CriteriaOperator = Me.AcceptOperator(theOperand.AggregatedExpression)
        Dim condition As CriteriaOperator = Me.AcceptOperator(theOperand.Condition)
        If Object.ReferenceEquals(theOperand.AggregatedExpression, aggregatedExpression) AndAlso Object.ReferenceEquals(theOperand.Condition, condition) Then
            Return theOperand
        End If
        Return New JoinOperand(theOperand.JoinTypeName, condition, theOperand.AggregateType, aggregatedExpression)
    End Function

    Protected Overridable Function VisitProperty(ByVal theOperand As OperandProperty) As CriteriaOperator
        Return theOperand
    End Function

    Protected Overridable Function VisitAggregate(ByVal theOperand As AggregateOperand) As CriteriaOperator
        Dim aggregatedExpression As CriteriaOperator = Me.AcceptOperator(theOperand.AggregatedExpression)
        Dim condition As CriteriaOperator = Me.AcceptOperator(theOperand.Condition)
        If Object.ReferenceEquals(theOperand.AggregatedExpression, aggregatedExpression) AndAlso Object.ReferenceEquals(theOperand.Condition, condition) Then
            Return theOperand
        End If
        Return New AggregateOperand(theOperand.CollectionProperty, aggregatedExpression, theOperand.AggregateType, condition)
    End Function

    Protected Overridable Function VisitFunction(ByVal theOperator As FunctionOperator) As CriteriaOperator
        Dim operands As CriteriaOperatorCollection = Me.VisitOperands(theOperator.Operands)
        If Object.ReferenceEquals(theOperator.Operands, operands) Then
            Return theOperator
        End If
        Return New FunctionOperator(theOperator.OperatorType, operands)
    End Function

    Protected Overridable Function VisitValue(ByVal theOperand As OperandValue) As CriteriaOperator
        Return theOperand
    End Function

    Protected Overridable Function VisitGroup(ByVal theOperator As GroupOperator) As CriteriaOperator
        Dim operands As CriteriaOperatorCollection = Me.VisitOperands(theOperator.Operands)
        If Object.ReferenceEquals(theOperator.Operands, operands) Then
            Return theOperator
        End If
        Return New GroupOperator(theOperator.OperatorType, operands)
    End Function

    Protected Overridable Function VisitIn(ByVal theOperator As InOperator) As CriteriaOperator
        Dim leftOperand As CriteriaOperator = Me.AcceptOperator(theOperator.LeftOperand)
        Dim operands As CriteriaOperatorCollection = Me.VisitOperands(theOperator.Operands)
        If Object.ReferenceEquals(theOperator.LeftOperand, leftOperand) AndAlso Object.ReferenceEquals(theOperator.Operands, operands) Then
            Return theOperator
        End If
        Return New InOperator(leftOperand, operands)
    End Function

    Protected Overridable Function VisitUnary(ByVal theOperator As UnaryOperator) As CriteriaOperator
        Dim operand As CriteriaOperator = Me.AcceptOperator(theOperator.Operand)
        If Object.ReferenceEquals(theOperator.Operand, operand) Then
            Return theOperator
        End If
        Return New UnaryOperator(theOperator.OperatorType, operand)
    End Function

    Protected Overridable Function VisitBinary(ByVal theOperator As BinaryOperator) As CriteriaOperator
        Dim leftOperand As CriteriaOperator = Me.AcceptOperator(theOperator.LeftOperand)
        Dim rightOperand As CriteriaOperator = Me.AcceptOperator(theOperator.RightOperand)
        If Object.ReferenceEquals(theOperator.LeftOperand, leftOperand) AndAlso Object.ReferenceEquals(theOperator.RightOperand, rightOperand) Then
            Return theOperator
        End If
        Return New BinaryOperator(leftOperand, rightOperand, theOperator.OperatorType)
    End Function

    Protected Overridable Function VisitBetween(ByVal theOperator As BetweenOperator) As CriteriaOperator
        Dim beginExpression As CriteriaOperator = Me.AcceptOperator(theOperator.BeginExpression)
        Dim endExpression As CriteriaOperator = Me.AcceptOperator(theOperator.EndExpression)
        Dim testExpression As CriteriaOperator = Me.AcceptOperator(theOperator.TestExpression)
        If Object.ReferenceEquals(theOperator.BeginExpression, beginExpression) AndAlso Object.ReferenceEquals(theOperator.EndExpression, endExpression) AndAlso Object.ReferenceEquals(theOperator.TestExpression, testExpression) Then
            Return theOperator
        End If
        Return New BetweenOperator(testExpression, beginExpression, endExpression)
    End Function

    #Region "IClientCriteriaVisitor"
    Private Function IClientCriteriaVisitorGeneric_Visit(ByVal theOperand As JoinOperand) As CriteriaOperator Implements IClientCriteriaVisitor(Of CriteriaOperator).Visit
        Return Me.VisitJoin(theOperand)
    End Function

    Private Function IClientCriteriaVisitorGeneric_Visit(ByVal theOperand As OperandProperty) As CriteriaOperator Implements IClientCriteriaVisitor(Of CriteriaOperator).Visit
        Return Me.VisitProperty(theOperand)
    End Function

    Private Function IClientCriteriaVisitorGeneric_Visit(ByVal theOperand As AggregateOperand) As CriteriaOperator Implements IClientCriteriaVisitor(Of CriteriaOperator).Visit
        Return Me.VisitAggregate(theOperand)
    End Function
    #End Region
    #Region "ICriteriaVisitor"
    Private Function ICriteriaVisitorGeneric_Visit(ByVal theOperator As FunctionOperator) As CriteriaOperator Implements ICriteriaVisitor(Of CriteriaOperator).Visit
        Return Me.VisitFunction(theOperator)
    End Function

    Private Function ICriteriaVisitorGeneric_Visit(ByVal theOperand As OperandValue) As CriteriaOperator Implements ICriteriaVisitor(Of CriteriaOperator).Visit
        Return Me.VisitValue(theOperand)
    End Function

    Private Function ICriteriaVisitorGeneric_Visit(ByVal theOperator As GroupOperator) As CriteriaOperator Implements ICriteriaVisitor(Of CriteriaOperator).Visit
        Return Me.VisitGroup(theOperator)
    End Function

    Private Function ICriteriaVisitorGeneric_Visit(ByVal theOperator As InOperator) As CriteriaOperator Implements ICriteriaVisitor(Of CriteriaOperator).Visit
        Return Me.VisitIn(theOperator)
    End Function

    Private Function ICriteriaVisitorGeneric_Visit(ByVal theOperator As UnaryOperator) As CriteriaOperator Implements ICriteriaVisitor(Of CriteriaOperator).Visit
        Return Me.VisitUnary(theOperator)
    End Function

    Private Function ICriteriaVisitorGeneric_Visit(ByVal theOperator As BinaryOperator) As CriteriaOperator Implements ICriteriaVisitor(Of CriteriaOperator).Visit
        Return Me.VisitBinary(theOperator)
    End Function

    Private Function ICriteriaVisitorGeneric_Visit(ByVal theOperator As BetweenOperator) As CriteriaOperator Implements ICriteriaVisitor(Of CriteriaOperator).Visit
        Return Me.VisitBetween(theOperator)
    End Function
    #End Region
End Class

App_Code/CriteriaVisitor.cs(vb)

C#
VB.NET

C#
using DevExpress.Data.Filtering;
using System;
using System.Linq;

public class CriteriaVisitor : CriteriaPatcherBase {
    enum CustomVisitMode { LookingOnlyForCustomOperator, RemoveCustomOperator }
    public static CriteriaOperator RemoveCustomFunction(CriteriaOperator theOperator, string fieldName) {
        return new CriteriaVisitor(fieldName, CustomVisitMode.RemoveCustomOperator).AcceptOperator(theOperator);
    }
    public static string GetCustomFunctionOperatorValue(CriteriaOperator theOperator, string fieldName) {
        var myFunctionOperator = new CriteriaVisitor(fieldName, CustomVisitMode.LookingOnlyForCustomOperator).AcceptOperator(theOperator) as FunctionOperator;
        if(!IsNull(myFunctionOperator))
            return ((ConstantValue)myFunctionOperator.Operands[1]).Value.ToString();
        return null;
    }

    CriteriaVisitor(String fieldName, CustomVisitMode visitMode) {
        FieldName = fieldName;
        VisitMode = visitMode;
    }

    protected string FieldName { get; private set; }
    CustomVisitMode VisitMode { get; set; }

    protected override CriteriaOperator VisitFunction(FunctionOperator theOperator) {
        if(IsMyCustomFunctionOperator(theOperator))
            return VisitMode == CustomVisitMode.LookingOnlyForCustomOperator ? theOperator : null;
        if(VisitMode == CustomVisitMode.RemoveCustomOperator)
            return base.VisitFunction(theOperator);
        return null;
    }
    protected override CriteriaOperator VisitGroup(GroupOperator theOperator) {
        var operands = VisitOperands(theOperator.Operands).Where(op => !IsNull(op));
        if(VisitMode == CustomVisitMode.LookingOnlyForCustomOperator)
            return operands.FirstOrDefault(op => IsMyCustomFunctionOperator(op as FunctionOperator));
        return new GroupOperator(theOperator.OperatorType, operands);
    }
    protected bool IsMyCustomFunctionOperator(FunctionOperator criteria) {
        if(IsNull(criteria) || criteria.OperatorType != FunctionOperatorType.Custom)
            return false;
        var operands = criteria.Operands;
        if(operands.Count != 4)
            return false;
        var customFunctionName = operands[0] as ConstantValue;
        var stateOperand = operands[1] as OperandValue;
        var columnOperand = operands[2] as OperandProperty;
        if(IsNull(customFunctionName) || IsNull(stateOperand) || IsNull(columnOperand))
            return false;
        return customFunctionName.Value.ToString() == MyCustomFunctionOperator.Name && columnOperand.PropertyName == FieldName;
    }
}

Visual Basic
Imports DevExpress.Data.Filtering
Imports System
Imports System.Linq

Public Class CriteriaVisitor
    Inherits CriteriaPatcherBase

    Private Enum CustomVisitMode
        LookingOnlyForCustomOperator
        RemoveCustomOperator
    End Enum
    Public Shared Function RemoveCustomFunction(ByVal theOperator As CriteriaOperator, ByVal fieldName As String) As CriteriaOperator
        Return (New CriteriaVisitor(fieldName, CustomVisitMode.RemoveCustomOperator)).AcceptOperator(theOperator)
    End Function
    Public Shared Function GetCustomFunctionOperatorValue(ByVal theOperator As CriteriaOperator, ByVal fieldName As String) As String
        Dim myFunctionOperator = TryCast((New CriteriaVisitor(fieldName, CustomVisitMode.LookingOnlyForCustomOperator)).AcceptOperator(theOperator), FunctionOperator)
        If Not IsNull(myFunctionOperator) Then
            Return CType(myFunctionOperator.Operands(1), ConstantValue).Value.ToString()
        End If
        Return Nothing
    End Function

    Private Sub New(ByVal fieldName As String, ByVal visitMode As CustomVisitMode)
        Me.FieldName = fieldName
        Me.VisitMode = visitMode
    End Sub

    Private privateFieldName As String
    Protected Property FieldName() As String
        Get
            Return privateFieldName
        End Get
        Private Set(ByVal value As String)
            privateFieldName = value
        End Set
    End Property
    Private Property VisitMode() As CustomVisitMode

    Protected Overrides Function VisitFunction(ByVal theOperator As FunctionOperator) As CriteriaOperator
        If IsMyCustomFunctionOperator(theOperator) Then
            Return If(VisitMode = CustomVisitMode.LookingOnlyForCustomOperator, theOperator, Nothing)
        End If
        If VisitMode = CustomVisitMode.RemoveCustomOperator Then
            Return MyBase.VisitFunction(theOperator)
        End If
        Return Nothing
    End Function
    Protected Overrides Function VisitGroup(ByVal theOperator As GroupOperator) As CriteriaOperator
        Dim operands = VisitOperands(theOperator.Operands).Where(Function(op) Not IsNull(op))
        If VisitMode = CustomVisitMode.LookingOnlyForCustomOperator Then
            Return operands.FirstOrDefault(Function(op) IsMyCustomFunctionOperator(TryCast(op, FunctionOperator)))
        End If
        Return New GroupOperator(theOperator.OperatorType, operands)
    End Function
    Protected Function IsMyCustomFunctionOperator(ByVal criteria As FunctionOperator) As Boolean
        If IsNull(criteria) OrElse criteria.OperatorType <> FunctionOperatorType.Custom Then
            Return False
        End If
        Dim operands = criteria.Operands
        If operands.Count <> 4 Then
            Return False
        End If
        Dim customFunctionName = TryCast(operands(0), ConstantValue)
        Dim stateOperand = TryCast(operands(1), OperandValue)
        Dim columnOperand = TryCast(operands(2), OperandProperty)
        If IsNull(customFunctionName) OrElse IsNull(stateOperand) OrElse IsNull(columnOperand) Then
            Return False
        End If
        Return customFunctionName.Value.ToString() = MyCustomFunctionOperator.Name AndAlso columnOperand.PropertyName = FieldName
    End Function
End Class

App_Code/MyCustomFunctionOperator.cs(vb)

C#
VB.NET

C#
using DevExpress.Data.Filtering;
using System;

public class MyCustomFunctionOperator : ICustomFunctionOperator {
    public static string Name { get { return "MyFunctionOperator"; } }

    object ICustomFunctionOperator.Evaluate(params object[] operands) {
        if(operands.Length == 3) {
            var state = operands[0] as string;
            if(!string.IsNullOrEmpty(state)) {
                var shippedDate = !ReferenceEquals(operands[1], null) ? Convert.ToDateTime(operands[1]) : DateTime.MaxValue;
                var requiredDate = !ReferenceEquals(operands[2], null) ? Convert.ToDateTime(operands[2]) : DateTime.MaxValue;
                switch(state) {
                    case "OK":
                        return shippedDate <= requiredDate;
                    case "NOTOK":
                        return shippedDate > requiredDate && shippedDate != DateTime.MaxValue;
                    case "ISSUE":
                        return shippedDate == DateTime.MaxValue;
                }
            }
        }
        return true;
    }

    string ICustomFunctionOperator.Name { get { return Name; } }
    Type ICustomFunctionOperator.ResultType(params Type[] operands) { return typeof(bool); }
}

Visual Basic
Imports DevExpress.Data.Filtering
Imports System

Public Class MyCustomFunctionOperator
    Implements ICustomFunctionOperator

    Public Shared ReadOnly Property Name() As String
        Get
            Return "MyFunctionOperator"
        End Get
    End Property

    Private Function ICustomFunctionOperator_Evaluate(ParamArray ByVal operands() As Object) As Object Implements ICustomFunctionOperator.Evaluate
        If operands.Length = 3 Then
            Dim state = TryCast(operands(0), String)
            If Not String.IsNullOrEmpty(state) Then
                Dim shippedDate = If(Not ReferenceEquals(operands(1), Nothing), Convert.ToDateTime(operands(1)), DateTime.MaxValue)
                Dim requiredDate = If(Not ReferenceEquals(operands(2), Nothing), Convert.ToDateTime(operands(2)), DateTime.MaxValue)
                Select Case state
                    Case "OK"
                        Return shippedDate <= requiredDate
                    Case "NOTOK"
                        Return shippedDate > requiredDate AndAlso shippedDate <> DateTime.MaxValue
                    Case "ISSUE"
                        Return shippedDate = DateTime.MaxValue
                End Select
            End If
        End If
        Return True
    End Function

    Private ReadOnly Property ICustomFunctionOperator_Name() As String Implements ICustomFunctionOperator.Name
        Get
            Return Name
        End Get
    End Property
    Private Function ICustomFunctionOperator_ResultType(ParamArray ByVal operands() As Type) As Type Implements ICustomFunctionOperator.ResultType
        Return GetType(Boolean)
    End Function
End Class

Default.aspx

ASPx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>

<%@ Register Assembly="DevExpress.Web.v16.2, Version=16.2.17.0, Culture=neutral, PublicKeyToken=b88d1754d700e49a" Namespace="DevExpress.Web" TagPrefix="dx" %>

<!DOCTYPE html>

<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>ASPxGridView - How to apply Custom Function Filter Criteria Operator</title>
</head>
<body>
    <h2>ASPxGridView - How to apply Custom Function Filter Criteria Operator</h2>

    <form id="form1" runat="server">
        <div>
            <dx:ASPxGridView ID="Grid" runat="server" DataSourceID="SqlDataSource1"
                OnAutoFilterCellEditorCreate="Grid_AutoFilterCellEditorCreate"
                OnAutoFilterCellEditorInitialize="Grid_AutoFilterCellEditorInitialize"
                OnProcessColumnAutoFilter="Grid_ProcessColumnAutoFilter">
                <Columns>
                    <dx:GridViewDataTextColumn FieldName="ShipName" />
                    <dx:GridViewDataTextColumn FieldName="ProductName" />
                    <dx:GridViewDataDateColumn FieldName="ShippedDate" Caption="Date of delivery" HeaderStyle-BackColor="Wheat" />
                    <dx:GridViewDataDateColumn FieldName="RequiredDate" Caption="Expiration date of delivery"
                        HeaderStyle-BackColor="Wheat" Settings-AllowAutoFilter="False" />
                </Columns>
                <Settings ShowFilterRow="true" />
            </dx:ASPxGridView>
            <asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:ConnectionString %>" 
                ProviderName="<%$ ConnectionStrings:ConnectionString.ProviderName %>" 
                SelectCommand="SELECT [ShipName], [ProductName], [ShippedDate], [RequiredDate] FROM [Invoices]" />
        </div>
    </form>
</body>
</html>

Default.aspx.cs(vb)

C#
VB.NET

C#
using DevExpress.Data.Filtering;
using DevExpress.Web;
using System;

public partial class _Default : System.Web.UI.Page {
    const string
        SpecialFilterColumnFieldName = "ShippedDate",
        OtherFilterColumnFieldName = "RequiredDate";

    protected void Page_Init(object sender, EventArgs e) {
        CriteriaOperator.RegisterCustomFunction(new MyCustomFunctionOperator());
    }

    protected void Grid_ProcessColumnAutoFilter(object sender, DevExpress.Web.ASPxGridViewAutoFilterEventArgs e) {
        var grid = (ASPxGridView)sender;
        if(e.Column.FieldName == SpecialFilterColumnFieldName && e.Kind == GridViewAutoFilterEventKind.CreateCriteria) {
            grid.FilterExpression = UpdateGridFilterExpression(grid, e);
            e.Criteria = null;
        }
    }

    protected string UpdateGridFilterExpression(ASPxGridView grid, ASPxGridViewAutoFilterEventArgs e) {
        var gridCriteria = CriteriaOperator.Parse(grid.FilterExpression);
        gridCriteria = CriteriaVisitor.RemoveCustomFunction(gridCriteria, e.Column.FieldName);

        var customCriteria = new FunctionOperator(FunctionOperatorType.Custom, MyCustomFunctionOperator.Name, e.Value, new OperandProperty(e.Column.FieldName), new OperandProperty(OtherFilterColumnFieldName));
        if(ReferenceEquals(gridCriteria, null) && ReferenceEquals(customCriteria, null))
            return string.Empty;
        return GroupOperator.And(gridCriteria, customCriteria).ToString();
    }

    protected void Grid_AutoFilterCellEditorCreate(object sender, ASPxGridViewEditorCreateEventArgs e) {
        if(e.Column.FieldName == SpecialFilterColumnFieldName)
            e.EditorProperties = new ComboBoxProperties();
    }

    protected void Grid_AutoFilterCellEditorInitialize(object sender, ASPxGridViewEditorEventArgs e) {
        var grid = (ASPxGridView)sender;
        if(e.Column.FieldName == SpecialFilterColumnFieldName) {
            InitializeFilterCombobox((ASPxComboBox)e.Editor);

            var gridCriteria = CriteriaOperator.Parse(grid.FilterExpression);
            e.Editor.Value = CriteriaVisitor.GetCustomFunctionOperatorValue(gridCriteria, e.Column.FieldName);
        }
    }

    protected void InitializeFilterCombobox(ASPxComboBox editor) {
        editor.ValueType = typeof(string);
        editor.Items.Add("Delivered in time", "OK");
        editor.Items.Add("Delivered with delay", "NOTOK");
        editor.Items.Add("Delivery lost", "ISSUE");
    }
}

Visual Basic
Imports DevExpress.Data.Filtering
Imports DevExpress.Web
Imports System

Partial Public Class _Default
    Inherits System.Web.UI.Page

    Private Const SpecialFilterColumnFieldName As String = "ShippedDate", OtherFilterColumnFieldName As String = "RequiredDate"

    Protected Sub Page_Init(ByVal sender As Object, ByVal e As EventArgs)
        CriteriaOperator.RegisterCustomFunction(New MyCustomFunctionOperator())
    End Sub

    Protected Sub Grid_ProcessColumnAutoFilter(ByVal sender As Object, ByVal e As DevExpress.Web.ASPxGridViewAutoFilterEventArgs)
        Dim grid = DirectCast(sender, ASPxGridView)
        If e.Column.FieldName = SpecialFilterColumnFieldName AndAlso e.Kind = GridViewAutoFilterEventKind.CreateCriteria Then
            grid.FilterExpression = UpdateGridFilterExpression(grid, e)
            e.Criteria = Nothing
        End If
    End Sub

    Protected Function UpdateGridFilterExpression(ByVal grid As ASPxGridView, ByVal e As ASPxGridViewAutoFilterEventArgs) As String
        Dim gridCriteria = CriteriaOperator.Parse(grid.FilterExpression)
        gridCriteria = CriteriaVisitor.RemoveCustomFunction(gridCriteria, e.Column.FieldName)

        Dim customCriteria = New FunctionOperator(FunctionOperatorType.Custom, MyCustomFunctionOperator.Name, e.Value, New OperandProperty(e.Column.FieldName), New OperandProperty(OtherFilterColumnFieldName))
        If ReferenceEquals(gridCriteria, Nothing) AndAlso ReferenceEquals(customCriteria, Nothing) Then
            Return String.Empty
        End If
        Return GroupOperator.And(gridCriteria, customCriteria).ToString()
    End Function

    Protected Sub Grid_AutoFilterCellEditorCreate(ByVal sender As Object, ByVal e As ASPxGridViewEditorCreateEventArgs)
        If e.Column.FieldName = SpecialFilterColumnFieldName Then
            e.EditorProperties = New ComboBoxProperties()
        End If
    End Sub

    Protected Sub Grid_AutoFilterCellEditorInitialize(ByVal sender As Object, ByVal e As ASPxGridViewEditorEventArgs)
        Dim grid = DirectCast(sender, ASPxGridView)
        If e.Column.FieldName = SpecialFilterColumnFieldName Then
            InitializeFilterCombobox(CType(e.Editor, ASPxComboBox))

            Dim gridCriteria = CriteriaOperator.Parse(grid.FilterExpression)
            e.Editor.Value = CriteriaVisitor.GetCustomFunctionOperatorValue(gridCriteria, e.Column.FieldName)
        End If
    End Sub

    Protected Sub InitializeFilterCombobox(ByVal editor As ASPxComboBox)
        editor.ValueType = GetType(String)
        editor.Items.Add("Delivered in time", "OK")
        editor.Items.Add("Delivered with delay", "NOTOK")
        editor.Items.Add("Delivery lost", "ISSUE")
    End Sub
End Class

DevExpress Support Team

last modified 2 years ago

Modified: June 9, 2023 8:33 AM

Platform: ASP.NET Web Forms

Product: ASPxGridView

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Grid View for ASP.NET Web Forms - How to apply custom function filter criteria operators

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