BindableObjectExtensions.SetBinding Method
Definition
Important
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Overloads
SetBinding(BindableObject, BindableProperty, String, BindingMode, IValueConverter, String) |
Creates and applies a binding to a property. |
SetBinding<TSource,TProperty>(BindableObject, BindableProperty, Func<TSource,TProperty>, BindingMode, IValueConverter, Object, String, Object, Object, Object) |
Creates a binding between a property on the source object and a property on the target object. |
SetBinding(BindableObject, BindableProperty, String, BindingMode, IValueConverter, String)
- Source:
- BindableObjectExtensions.cs
- Source:
- BindableObjectExtensions.cs
Creates and applies a binding to a property.
public static void SetBinding (this Microsoft.Maui.Controls.BindableObject self, Microsoft.Maui.Controls.BindableProperty targetProperty, string path, Microsoft.Maui.Controls.BindingMode mode = Microsoft.Maui.Controls.BindingMode.Default, Microsoft.Maui.Controls.IValueConverter converter = default, string stringFormat = default);
static member SetBinding : Microsoft.Maui.Controls.BindableObject * Microsoft.Maui.Controls.BindableProperty * string * Microsoft.Maui.Controls.BindingMode * Microsoft.Maui.Controls.IValueConverter * string -> unit
<Extension()>
Public Sub SetBinding (self As BindableObject, targetProperty As BindableProperty, path As String, Optional mode As BindingMode = Microsoft.Maui.Controls.BindingMode.Default, Optional converter As IValueConverter = Nothing, Optional stringFormat As String = Nothing)
Parameters
- self
- BindableObject
The BindableObject.
- targetProperty
- BindableProperty
The BindableProperty on which to set a binding.
- mode
- BindingMode
The BindingMode for the binding. This parameter is optional. Default is Default.
- converter
- IValueConverter
An IValueConverter for the binding. This parameter is optional. Default is null
.
- stringFormat
- String
A string used as stringFormat for the binding. This parameter is optional. Default is null
.
Remarks
The following example shows how to use the extension method to set a binding.
public class PersonViewModel
{
public string Name { get; set; }
public string Company { get; set; }
}
// ...
var vm = new PersonViewModel {
Name = "John Doe",
Company = "Xamarin"
}
var label = new Label ();
label.SetBinding (Label.TextProperty, "Name"); // "Name" is the property on the view model
label.BindingContext = vm;
Debug.WriteLine (label.Text); // prints "John Doe"
Applies to
SetBinding<TSource,TProperty>(BindableObject, BindableProperty, Func<TSource,TProperty>, BindingMode, IValueConverter, Object, String, Object, Object, Object)
- Source:
- BindableObjectExtensions.cs
Creates a binding between a property on the source object and a property on the target object.
public static void SetBinding<TSource,TProperty> (this Microsoft.Maui.Controls.BindableObject self, Microsoft.Maui.Controls.BindableProperty targetProperty, Func<TSource,TProperty> getter, Microsoft.Maui.Controls.BindingMode mode = Microsoft.Maui.Controls.BindingMode.Default, Microsoft.Maui.Controls.IValueConverter? converter = default, object? converterParameter = default, string? stringFormat = default, object? source = default, object? fallbackValue = default, object? targetNullValue = default);
static member SetBinding : Microsoft.Maui.Controls.BindableObject * Microsoft.Maui.Controls.BindableProperty * Func<'Source, 'Property> * Microsoft.Maui.Controls.BindingMode * Microsoft.Maui.Controls.IValueConverter * obj * string * obj * obj * obj -> unit
<Extension()>
Public Sub SetBinding(Of TSource, TProperty) (self As BindableObject, targetProperty As BindableProperty, getter As Func(Of TSource, TProperty), Optional mode As BindingMode = Microsoft.Maui.Controls.BindingMode.Default, Optional converter As IValueConverter = Nothing, Optional converterParameter As Object = Nothing, Optional stringFormat As String = Nothing, Optional source As Object = Nothing, Optional fallbackValue As Object = Nothing, Optional targetNullValue As Object = Nothing)
Type Parameters
- TSource
The source type.
- TProperty
The property type.
Parameters
- self
- BindableObject
The BindableObject.
- targetProperty
- BindableProperty
The BindableProperty on which to set a binding.
- getter
- Func<TSource,TProperty>
An getter method used to retrieve the source property.
- mode
- BindingMode
The binding mode. This property is optional. Default is Default.
- converter
- IValueConverter
The converter. This parameter is optional. Default is null
.
- converterParameter
- Object
An user-defined parameter to pass to the converter. This parameter is optional. Default is null
.
- stringFormat
- String
A String format. This parameter is optional. Default is null
.
- source
- Object
An object used as the source for this binding. This parameter is optional. Default is null
.
- fallbackValue
- Object
The value to use instead of the default value for the property, if no specified value exists.
- targetNullValue
- Object
The value to supply for a bound property when the target of the binding is null
.
Exceptions
Remarks
The following example illustrates the setting of a binding using the extension method.
public class PersonViewModel
{
public string Name { get; set; }
public Address? Address { get; set; }
// ...
}
var vm = new PersonViewModel { Name = "John Doe" };
var label = new Label();
label.SetBinding(Label.TextProperty, static (PersonViewModel vm) => vm.Name);
label.BindingContext = vm;
vm.Name = "Jane Doe";
Debug.WriteLine(label.Text); // prints "Jane Doe"
Not all methods can be used to define a binding. The expression must be a simple property access expression. The following are examples of valid and invalid expressions:
// Valid: Property access
static (PersonViewModel vm) => vm.Name;
static (PersonViewModel vm) => vm.Address?.Street;
// Valid: Array and indexer access
static (PersonViewModel vm) => vm.PhoneNumbers[0];
static (PersonViewModel vm) => vm.Config["Font"];
// Valid: Casts
static (Label label) => (label.BindingContext as PersonViewModel).Name;
static (Label label) => ((PersonViewModel)label.BindingContext).Name;
// Invalid: Method calls
static (PersonViewModel vm) => vm.GetAddress();
static (PersonViewModel vm) => vm.Address?.ToString();
// Invalid: Complex expressions
static (PersonViewModel vm) => vm.Address?.Street + " " + vm.Address?.City;
static (PersonViewModel vm) => $"Name: {vm.Name}";
Applies to
.NET MAUI