Occurs before the list of menu items has been populated with the default
FilterTools.
The event handler receives an argument of type BeforeMenuPopulateEventArgs containing data related to this event. The following BeforeMenuPopulateEventArgs properties provide information specific to this event.
The following code illustrates how to create a simple class that derives from SpecialFilterOperand to allow the filtering of odd or even integers. This class is then used to manually populate the list of items shown by the filter provider.
For an overview of how to handle events in Visual Basic or Visual C#, see
Event Handlers in Visual Basic and Visual C#. For specific information and code examples illustrating how to consume events in your application, see
Consuming Events in the
.NET Framework Developer's Guide.
Imports Infragistics.Win.UltraWinGrid
Imports Infragistics.Win.SupportDialogs.FilterUIProvider
Public Class OddEvenSpecialOperand
Inherits SpecialFilterOperand
Private isOdd As Boolean
Public Sub New(ByVal isOdd As Boolean)
MyBase.New(If(isOdd, "Odd", "Even"))
Me.isOdd = isOdd
End Sub
Public Overloads Overrides Function Match(ByVal comparisonOperator As FilterComparisionOperator, ByVal value As Object) As Boolean
If value Is Nothing OrElse value Is DBNull.Value Then
Return False
End If
Dim modVal As Integer = CInt(value) Mod 2
Return If(isOdd, modVal <> 0, modVal = 0)
End Function
Public Overloads Overrides Function SupportsDataType(ByVal dataType As Type) As Boolean
' We only want to be able to perform this comparison on an integer
Dim underlyingType As Type = Infragistics.Win.Utilities.GetUnderlyingType(dataType)
Return underlyingType Is GetType(Integer)
End Function
Public Overloads Overrides Function SupportsOperator(ByVal comparisonOperator As FilterComparisionOperator) As Boolean
' It doesn't really make any sense to say that something is "less than" an odd or even number,
' so only allow "Equals" comparisons
Return comparisonOperator = FilterComparisionOperator.Equals
End Function
End Class
Private _evenOperand As OddEvenSpecialOperand
Public ReadOnly Property EvenOperand() As OddEvenSpecialOperand
Get
If Me._evenOperand Is Nothing Then
Me._evenOperand = New OddEvenSpecialOperand(False)
End If
Return Me._evenOperand
End Get
End Property
Private _oddOperand As OddEvenSpecialOperand
Public ReadOnly Property OddOperand() As OddEvenSpecialOperand
Get
If Me._oddOperand Is Nothing Then
Me._oddOperand = New OddEvenSpecialOperand(True)
End If
Return Me._oddOperand
End Get
End Property
Private Sub ultraGridFilterUIProvider1_BeforeMenuPopulate(ByVal sender As Object, ByVal e As BeforeMenuPopulateEventArgs)
' Mark the event as handled since we will be adding our own items
e.Handled = True
Dim filterConditions As FilterConditionsCollection = e.ColumnFilter.FilterConditions
' Add only two operands, "Even" and "Odd". Note that we use cached operands since we
' want to be able to check to see if we've already applied the operand and update the
' checked status accordingly
Dim oddTool As New FilterOperandTool("Odd", Me.OddOperand)
Dim evenTool As New FilterOperandTool("Even", Me.EvenOperand)
For i As Integer = 0 To filterConditions.Count - 1
Dim condition As FilterCondition = filterConditions(i)
If condition.ComparisionOperator = FilterComparisionOperator.Equals Then
If condition.CompareValue Is Me.OddOperand Then
oddTool.Checked = True
ElseIf condition.CompareValue Is Me.EvenOperand Then
evenTool.Checked = True
End If
End If
Next
e.MenuItems.Add(evenTool)
e.MenuItems.Add(oddTool)
End Sub
using Infragistics.Win.UltraWinGrid;
using Infragistics.Win.SupportDialogs.FilterUIProvider;
public class OddEvenSpecialOperand : SpecialFilterOperand
{
private bool isOdd;
public OddEvenSpecialOperand(bool isOdd) :
base(isOdd ? "Odd" : "Even")
{
this.isOdd = isOdd;
}
public override bool Match(FilterComparisionOperator comparisonOperator, object value)
{
if (value == null || value == DBNull.Value)
return false;
int modVal = (int)value % 2;
return isOdd ? modVal != 0 : modVal == 0;
}
public override bool SupportsDataType(Type dataType)
{
// We only want to be able to perform this comparison on an integer
Type underlyingType = Infragistics.Win.Utilities.GetUnderlyingType(dataType);
return underlyingType == typeof(int);
}
public override bool SupportsOperator(FilterComparisionOperator comparisonOperator)
{
// It doesn't really make any sense to say that something is "less than" an odd or even number,
// so only allow "Equals" comparisons
return comparisonOperator == FilterComparisionOperator.Equals;
}
}
private OddEvenSpecialOperand evenOperand;
public OddEvenSpecialOperand EvenOperand
{
get
{
if (this.evenOperand == null)
this.evenOperand = new OddEvenSpecialOperand(false);
return this.evenOperand;
}
}
private OddEvenSpecialOperand oddOperand;
public OddEvenSpecialOperand OddOperand
{
get
{
if (this.oddOperand == null)
this.oddOperand = new OddEvenSpecialOperand(true);
return this.oddOperand;
}
}
private void ultraGridFilterUIProvider1_BeforeMenuPopulate(object sender, BeforeMenuPopulateEventArgs e)
{
// Mark the event as handled since we will be adding our own items
e.Handled = true;
FilterConditionsCollection filterConditions = e.ColumnFilter.FilterConditions;
// Add only two operands, "Even" and "Odd". Note that we use cached operands since we
// want to be able to check to see if we've already applied the operand and update the
// checked status accordingly
FilterOperandTool oddTool = new FilterOperandTool("Odd", this.OddOperand);
FilterOperandTool evenTool = new FilterOperandTool("Even", this.EvenOperand);
for (int i = 0; i < filterConditions.Count; i++)
{
FilterCondition condition = filterConditions[i];
if (condition.ComparisionOperator == FilterComparisionOperator.Equals)
{
if (condition.CompareValue == this.OddOperand)
oddTool.Checked = true;
else if (condition.CompareValue == this.EvenOperand)
evenTool.Checked = true;
}
}
e.MenuItems.Add(evenTool);
e.MenuItems.Add(oddTool);
}
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Server 2012, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
