AutoCompleteFilterPredicate<T> Delegate
Microsoft Silverlight will reach end of support after October 2021. Learn more.
Represents the filter used by the AutoCompleteBox control to determine whether an item is a possible match for the specified text.
Namespace: System.Windows.Controls
Assembly: System.Windows.Controls.Input (in System.Windows.Controls.Input.dll)
Syntax
'Declaration
Public Delegate Function AutoCompleteFilterPredicate(Of T) ( _
search As String, _
item As T _
) As Boolean
public delegate bool AutoCompleteFilterPredicate<T>(
string search,
T item
)
Type Parameters
- T
The type used for filtering the AutoCompleteBox. This type can be either a string or an object.
Parameters
- search
Type: System.String
The string used as the basis for filtering.
- item
Type: T
The item that is compared with the search parameter.
Return Value
Type: System.Boolean
true to indicate item is a possible match for search; otherwise false.
Remarks
This delegate is used by the ItemFilter and TextFilter properties of the AutoCompleteBox. When used with ItemFilter, T is an object. When used with TextFilter, T must be a string.
Examples
The following example shows how to set the FilterMode to Custom, and then set the ItemFilter property to a custom filter method for the Employee object. The custom filter returns matches from employees' first or last name. This code example requires a reference to the System.Windows.Controls.Input assembly.
Private employees As New List(Of Employee)()
Public Sub New()
InitializeComponent()
' Add some items to the employee list.
employees.Add(New Employee("Sells", "Chris", "csells", 1234))
employees.Add(New Employee("Cabatana", "Reina", "rcaba", 5678))
employees.Add(New Employee("Sprenger", "Christof", "cspreng", 9123))
employees.Add(New Employee("Brandel", "Jonas", "jbrandel", 4567))
employees.Add(New Employee("Bye", "Dennis", "dbye", 8912))
employees.Add(New Employee("Reid", "Miles", "mreid", 3456))
' Set the item source.
myACB.ItemsSource = employees
...
' Set the ItemFilter property to the search method.
myACB.ItemFilter = AddressOf SearchEmployees
...
End Sub
...
Private Function SearchEmployees(ByVal search As String, ByVal value As Object) As Boolean
' Cast the value to an Employee.
Dim emp As Employee = TryCast(value, Employee)
If emp IsNot Nothing Then
' Look for a match in the first and last names.
If emp.LastName.ToLower().StartsWith(search) Then
Return True
ElseIf emp.FirstName.ToLower().StartsWith(search) Then
Return True
End If
End If
' If no match, return false.
Return False
End Function
...
Public Class Employee
Private _LastName As String
Public Property LastName() As String
Get
Return _LastName
End Get
Set(ByVal value As String)
_LastName = value
End Set
End Property
Private _FirstName As String
Public Property FirstName() As String
Get
Return _FirstName
End Get
Set(ByVal value As String)
_FirstName = value
End Set
End Property
Private _EmailName As String
Public Property EmailName() As String
Get
Return _EmailName
End Get
Set(ByVal value As String)
_EmailName = value
End Set
End Property
Private _ID As Integer
Public Property ID() As Integer
Get
Return _ID
End Get
Set(ByVal value As Integer)
_ID = value
End Set
End Property
Public Sub New(ByVal empLastName As String, ByVal empFirstName As String, ByVal empEmail As String, ByVal empID As Integer)
LastName = empLastName
FirstName = empFirstName
EmailName = empEmail
ID = empID
End Sub
Public Overloads Overrides Function ToString() As String
Return ((("Employee: " & FirstName & " ") + LastName + System.Environment.NewLine & "Email: ") + EmailName + System.Environment.NewLine & "ID: ") + ID.ToString()
End Function
End Class
List<Employee> employees = new List<Employee>();
public MainPage()
{
InitializeComponent();
// Add some items to the employee list.
employees.Add(new Employee("Sells", "Chris", "csells", 1234));
employees.Add(new Employee("Cabatana", "Reina", "rcaba", 5678));
employees.Add(new Employee("Sprenger", "Christof", "cspreng", 9123));
employees.Add(new Employee("Brandel", "Jonas", "jbrandel", 4567));
employees.Add(new Employee("Bye", "Dennis", "dbye", 8912));
employees.Add(new Employee("Reid", "Miles", "mreid", 3456));
// Set the item source.
myACB.ItemsSource = employees;
...
// Set the ItemFilter property to the search method.
myACB.ItemFilter += SearchEmployees;
...
}
...
bool SearchEmployees(string search, object value)
{
// Cast the value to an Employee.
Employee emp = value as Employee;
if (emp != null)
{
// Look for a match in the first and last names.
if (emp.LastName.ToLower().StartsWith(search))
return true;
else if (emp.FirstName.ToLower().StartsWith(search))
return true;
}
// If no match, return false.
return false;
}
...
public class Employee
{
public string LastName { get; set; }
public string FirstName { get; set; }
public string EmailName { get; set; }
public int ID { get; set; }
public Employee(string empLastName, string empFirstName, string empEmail, int empID)
{
LastName = empLastName;
FirstName = empFirstName;
EmailName = empEmail;
ID = empID;
}
public override string ToString()
{
return "Employee: " + FirstName + " " +
LastName + System.Environment.NewLine +
"Email: " + EmailName + System.Environment.NewLine + "ID: " +
ID.ToString();
}
}
<StackPanel x:Name="LayoutRoot" Background="LightGray">
<TextBlock FontWeight="Bold" Text="AutoCompleteBox Custom Filter Example" Margin="5"/>
<StackPanel Orientation="Horizontal">
<TextBlock Text="Employee:" Margin="5" HorizontalAlignment="Left" VerticalAlignment="Center"/>
<sdk:AutoCompleteBox Height="75" Width="200" VerticalAlignment="Center" HorizontalAlignment="Right"
x:Name="myACB" FilterMode="Custom" ToolTipService.ToolTip="Enter employee name."/>
</StackPanel>
</StackPanel>
Version Information
Silverlight
Supported in: 5, 4, 3
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.
See Also