path: root/docs/Xamarin.Forms.Core/Xamarin.Forms/Binding.xml

<Type Name="Binding" FullName="Xamarin.Forms.Binding">
  <TypeSignature Language="C#" Value="public sealed class Binding : Xamarin.Forms.BindingBase" />
  <TypeSignature Language="ILAsm" Value=".class public auto ansi sealed beforefieldinit Binding extends Xamarin.Forms.BindingBase" />
  <AssemblyInfo>
    <AssemblyName>Xamarin.Forms.Core</AssemblyName>
    <AssemblyVersion>1.0.0.0</AssemblyVersion>
    <AssemblyVersion>1.1.0.0</AssemblyVersion>
    <AssemblyVersion>1.2.0.0</AssemblyVersion>
    <AssemblyVersion>1.3.0.0</AssemblyVersion>
    <AssemblyVersion>1.4.0.0</AssemblyVersion>
    <AssemblyVersion>1.5.0.0</AssemblyVersion>
    <AssemblyVersion>2.0.0.0</AssemblyVersion>
  </AssemblyInfo>
  <Base>
    <BaseTypeName>Xamarin.Forms.BindingBase</BaseTypeName>
  </Base>
  <Interfaces />
  <Docs>
    <summary>A single 1:1 immutable data binding.</summary>
    <remarks>This class is immutable.</remarks>
  </Docs>
  <Members>
    <Member MemberName=".ctor">
      <MemberSignature Language="C#" Value="public Binding ();" />
      <MemberSignature Language="ILAsm" Value=".method public hidebysig specialname rtspecialname instance void .ctor() cil managed" />
      <MemberType>Constructor</MemberType>
      <AssemblyInfo>
        <AssemblyVersion>1.0.0.0</AssemblyVersion>
        <AssemblyVersion>1.1.0.0</AssemblyVersion>
        <AssemblyVersion>1.2.0.0</AssemblyVersion>
        <AssemblyVersion>1.3.0.0</AssemblyVersion>
        <AssemblyVersion>1.4.0.0</AssemblyVersion>
        <AssemblyVersion>1.5.0.0</AssemblyVersion>
        <AssemblyVersion>2.0.0.0</AssemblyVersion>
      </AssemblyInfo>
      <Parameters />
      <Docs>
        <summary>Constructs and initializes a new instance of the <see cref="T:Xamarin.Forms.Binding" /> class.</summary>
        <remarks>
        </remarks>
      </Docs>
    </Member>
    <Member MemberName=".ctor">
      <MemberSignature Language="C#" Value="public Binding (string path, Xamarin.Forms.BindingMode mode = Xamarin.Forms.BindingMode.Default, Xamarin.Forms.IValueConverter converter = null, object converterParameter = null, string stringFormat = null);" />
      <MemberSignature Language="ILAsm" Value=".method public hidebysig specialname rtspecialname instance void .ctor(string path, valuetype Xamarin.Forms.BindingMode mode, class Xamarin.Forms.IValueConverter converter, object converterParameter, string stringFormat) cil managed" />
      <MemberType>Constructor</MemberType>
      <AssemblyInfo>
        <AssemblyVersion>1.0.0.0</AssemblyVersion>
        <AssemblyVersion>1.1.0.0</AssemblyVersion>
        <AssemblyVersion>1.2.0.0</AssemblyVersion>
      </AssemblyInfo>
      <Parameters>
        <Parameter Name="path" Type="System.String" />
        <Parameter Name="mode" Type="Xamarin.Forms.BindingMode" />
        <Parameter Name="converter" Type="Xamarin.Forms.IValueConverter" />
        <Parameter Name="converterParameter" Type="System.Object" />
        <Parameter Name="stringFormat" Type="System.String" />
      </Parameters>
      <Docs>
        <param name="path">The property path.</param>
        <param name="mode">The binding mode. This property is optional. Default is <see cref="E:Xamarin.Forms.BindingMode.Default" />.</param>
        <param name="converter">The converter. This parameter is optional. Default is <see langword="null" />.</param>
        <param name="converterParameter">An user-defined parameter to pass to the converter. This parameter is optional. Default is <see langword="null" />.</param>
        <param name="stringFormat">A String format. This parameter is optional. Default is <see langword="null" />.</param>
        <summary>Constructs and initializes a new instance of the <see cref="T:Xamarin.Forms.Binding" /> class.</summary>
        <remarks>
          <para>The following example shows how to set a binding to a property with a BindingMode and Converter:</para>
          <example>
            <code lang="C#"><![CDATA[
public class PersonViewModel
{
  public string Name { get; set; }
  public string Company { get; set; }
}

public class ReverseConverter : IValueConverter
{
  public object Convert (object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
  {
    var s = value as string;
    if (s == null)
      return value;
    return new string (s.Reverse ().ToArray ());
  }

  public object ConvertBack (object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
  {
    var s = value as string;
    if (s == null)
      return value;
    return new string (s.Reverse ().ToArray ());
  }
}

var label = new Label ();
PersonViewModel person;
label.BindingContext = person = new PersonViewModel { Name = "John Doe", Company= "Xamarin" };
label.SetBinding (Label.TextProperty, new Binding ("Name", mode: BindingMode.TwoWay, converter: new ReverseConverter ()));
Debug.WriteLine (label.Text); //prints "eoD nhoJ". ReverseConverter.Convert () is invoked in this case.

label.Text = "ooF";
Debug.WriteLine (person.Name); //prints "Foo". ReverseConverter.ConvertBack () is invoked in this case. The label Text change is propagated back as the BindingMode is TwoWay.
        ]]></code>
          </example>
        </remarks>
      </Docs>
    </Member>
    <Member MemberName=".ctor">
      <MemberSignature Language="C#" Value="public Binding (string path, Xamarin.Forms.BindingMode mode = Xamarin.Forms.BindingMode.Default, Xamarin.Forms.IValueConverter converter = null, object converterParameter = null, string stringFormat = null, object source = null);" />
      <MemberSignature Language="ILAsm" Value=".method public hidebysig specialname rtspecialname instance void .ctor(string path, valuetype Xamarin.Forms.BindingMode mode, class Xamarin.Forms.IValueConverter converter, object converterParameter, string stringFormat, object source) cil managed" />
      <MemberType>Constructor</MemberType>
      <AssemblyInfo>
        <AssemblyVersion>1.3.0.0</AssemblyVersion>
        <AssemblyVersion>1.4.0.0</AssemblyVersion>
        <AssemblyVersion>1.5.0.0</AssemblyVersion>
        <AssemblyVersion>2.0.0.0</AssemblyVersion>
      </AssemblyInfo>
      <Parameters>
        <Parameter Name="path" Type="System.String" />
        <Parameter Name="mode" Type="Xamarin.Forms.BindingMode" />
        <Parameter Name="converter" Type="Xamarin.Forms.IValueConverter" />
        <Parameter Name="converterParameter" Type="System.Object" />
        <Parameter Name="stringFormat" Type="System.String" />
        <Parameter Name="source" Type="System.Object" />
      </Parameters>
      <Docs>
        <param name="path">The property path.</param>
        <param name="mode">The binding mode. This property is optional. Default is <see cref="E:Xamarin.Forms.BindingMode.Default" />.</param>
        <param name="converter">The converter. This parameter is optional. Default is <see langword="null" />.</param>
        <param name="converterParameter">An user-defined parameter to pass to the converter. This parameter is optional. Default is <see langword="null" />.</param>
        <param name="stringFormat">A String format. This parameter is optional. Default is <see langword="null" />.</param>
        <param name="source">An object used as the source for this binding. This parameter is optional. Default is <see langword="null" />.</param>
        <summary>Constructs and initializes a new instance of the <see cref="T:Xamarin.Forms.Binding" /> class.</summary>
        <remarks>
          <para>The following example shows how to set a binding to a property with a BindingMode and Converter:</para>
          <example>
            <code lang="C#"><![CDATA[
public class PersonViewModel
{
  public string Name { get; set; }
  public string Company { get; set; }
}

public class ReverseConverter : IValueConverter
{
  public object Convert (object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
  {
    var s = value as string;
    if (s == null)
      return value;
    return new string (s.Reverse ().ToArray ());
  }

  public object ConvertBack (object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
  {
    var s = value as string;
    if (s == null)
      return value;
    return new string (s.Reverse ().ToArray ());
  }
}

var label = new Label ();
PersonViewModel person;
label.BindingContext = person = new PersonViewModel { Name = "John Doe", Company= "Xamarin" };
label.SetBinding (Label.TextProperty, new Binding ("Name", mode: BindingMode.TwoWay, converter: new ReverseConverter ()));
Debug.WriteLine (label.Text); //prints "eoD nhoJ". ReverseConverter.Convert () is invoked in this case.

label.Text = "ooF";
Debug.WriteLine (person.Name); //prints "Foo". ReverseConverter.ConvertBack () is invoked in this case. The label Text change is propagated back as the BindingMode is TwoWay.
        ]]></code>
          </example>
        </remarks>
      </Docs>
    </Member>
    <Member MemberName="Converter">
      <MemberSignature Language="C#" Value="public Xamarin.Forms.IValueConverter Converter { get; set; }" />
      <MemberSignature Language="ILAsm" Value=".property instance class Xamarin.Forms.IValueConverter Converter" />
      <MemberType>Property</MemberType>
      <AssemblyInfo>
        <AssemblyVersion>1.0.0.0</AssemblyVersion>
        <AssemblyVersion>1.1.0.0</AssemblyVersion>
        <AssemblyVersion>1.2.0.0</AssemblyVersion>
        <AssemblyVersion>1.3.0.0</AssemblyVersion>
        <AssemblyVersion>1.4.0.0</AssemblyVersion>
        <AssemblyVersion>1.5.0.0</AssemblyVersion>
        <AssemblyVersion>2.0.0.0</AssemblyVersion>
      </AssemblyInfo>
      <ReturnValue>
        <ReturnType>Xamarin.Forms.IValueConverter</ReturnType>
      </ReturnValue>
      <Docs>
        <summary>Gets or sets the converter to be used for this binding ?</summary>
        <value>An IValueConverter, or <see langword="null" />.</value>
        <remarks>
        </remarks>
      </Docs>
    </Member>
    <Member MemberName="ConverterParameter">
      <MemberSignature Language="C#" Value="public object ConverterParameter { get; set; }" />
      <MemberSignature Language="ILAsm" Value=".property instance object ConverterParameter" />
      <MemberType>Property</MemberType>
      <AssemblyInfo>
        <AssemblyVersion>1.0.0.0</AssemblyVersion>
        <AssemblyVersion>1.1.0.0</AssemblyVersion>
        <AssemblyVersion>1.2.0.0</AssemblyVersion>
        <AssemblyVersion>1.3.0.0</AssemblyVersion>
        <AssemblyVersion>1.4.0.0</AssemblyVersion>
        <AssemblyVersion>1.5.0.0</AssemblyVersion>
        <AssemblyVersion>2.0.0.0</AssemblyVersion>
      </AssemblyInfo>
      <ReturnValue>
        <ReturnType>System.Object</ReturnType>
      </ReturnValue>
      <Docs>
        <summary>Gets or sets the parameter passed as argument to the converter.</summary>
        <value>An object, or <see langword="null" />.</value>
        <remarks>
        </remarks>
      </Docs>
    </Member>
    <Member MemberName="Create&lt;TSource&gt;">
      <MemberSignature Language="C#" Value="public static Xamarin.Forms.Binding Create&lt;TSource&gt; (System.Linq.Expressions.Expression&lt;Func&lt;TSource,object&gt;&gt; propertyGetter, Xamarin.Forms.BindingMode mode = Xamarin.Forms.BindingMode.Default, Xamarin.Forms.IValueConverter converter = null, object converterParameter = null, string stringFormat = null);" />
      <MemberSignature Language="ILAsm" Value=".method public static hidebysig class Xamarin.Forms.Binding Create&lt;TSource&gt;(class System.Linq.Expressions.Expression`1&lt;class System.Func`2&lt;!!TSource, object&gt;&gt; propertyGetter, valuetype Xamarin.Forms.BindingMode mode, class Xamarin.Forms.IValueConverter converter, object converterParameter, string stringFormat) cil managed" />
      <MemberType>Method</MemberType>
      <AssemblyInfo>
        <AssemblyVersion>1.0.0.0</AssemblyVersion>
        <AssemblyVersion>1.1.0.0</AssemblyVersion>
        <AssemblyVersion>1.2.0.0</AssemblyVersion>
        <AssemblyVersion>1.3.0.0</AssemblyVersion>
        <AssemblyVersion>1.4.0.0</AssemblyVersion>
        <AssemblyVersion>1.5.0.0</AssemblyVersion>
        <AssemblyVersion>2.0.0.0</AssemblyVersion>
      </AssemblyInfo>
      <Attributes>
        <Attribute>
          <AttributeName>System.Obsolete</AttributeName>
        </Attribute>
      </Attributes>
      <ReturnValue>
        <ReturnType>Xamarin.Forms.Binding</ReturnType>
      </ReturnValue>
      <TypeParameters>
        <TypeParameter Name="TSource" />
      </TypeParameters>
      <Parameters>
        <Parameter Name="propertyGetter" Type="System.Linq.Expressions.Expression&lt;System.Func&lt;TSource,System.Object&gt;&gt;" />
        <Parameter Name="mode" Type="Xamarin.Forms.BindingMode" />
        <Parameter Name="converter" Type="Xamarin.Forms.IValueConverter" />
        <Parameter Name="converterParameter" Type="System.Object" />
        <Parameter Name="stringFormat" Type="System.String" />
      </Parameters>
      <Docs>
        <typeparam name="TSource">The type of the source of the binding.</typeparam>
        <param name="propertyGetter">An expression used to retrieve the binding path.</param>
        <param name="mode">The binding mode. This property is optional. Default is <see cref="E:Xamarin.Forms.BindingMode.Default" />.</param>
        <param name="converter">The converter. This parameter is optional. Default is <see langword="null" />.</param>
        <param name="converterParameter">An user-defined parameter to pass to the converter. This parameter is optional. Default is <see langword="null" />.</param>
        <param name="stringFormat">A String format. This parameter is optional. Default is <see langword="null" />.</param>
        <summary>This is a convenient factory method to create a binding from an expression, instead of a property name. This api is more resilient to refactoring.</summary>
        <returns>A newly created binding.</returns>
        <remarks>
          <para>The following example shows how to set a binding to a property :</para>
          <example>
            <code lang="C#"><![CDATA[
public class PersonViewModel
{
  public string Name { get; set; }
  public string Company { get; set; }
}

var label = new Label ();
PersonViewModel person;
label.BindingContext = person = new PersonViewModel { Name = "John Doe", Company= "Xamarin" };
label.SetBinding (Label.TextProperty, Binding.Create<PersonViewModel> (vm => vm.Name));
Debug.WriteLine (label.Text); //prints "John Doe".
        ]]></code>
          </example>
        </remarks>
      </Docs>
    </Member>
    <Member MemberName="Path">
      <MemberSignature Language="C#" Value="public string Path { get; set; }" />
      <MemberSignature Language="ILAsm" Value=".property instance string Path" />
      <MemberType>Property</MemberType>
      <AssemblyInfo>
        <AssemblyVersion>1.0.0.0</AssemblyVersion>
        <AssemblyVersion>1.1.0.0</AssemblyVersion>
        <AssemblyVersion>1.2.0.0</AssemblyVersion>
        <AssemblyVersion>1.3.0.0</AssemblyVersion>
        <AssemblyVersion>1.4.0.0</AssemblyVersion>
        <AssemblyVersion>1.5.0.0</AssemblyVersion>
        <AssemblyVersion>2.0.0.0</AssemblyVersion>
      </AssemblyInfo>
      <ReturnValue>
        <ReturnType>System.String</ReturnType>
      </ReturnValue>
      <Docs>
        <summary>Gets or sets the path of the property</summary>
        <value>A string indicating the path to the property.</value>
        <remarks>
        </remarks>
      </Docs>
    </Member>
    <Member MemberName="Source">
      <MemberSignature Language="C#" Value="public object Source { get; set; }" />
      <MemberSignature Language="ILAsm" Value=".property instance object Source" />
      <MemberType>Property</MemberType>
      <AssemblyInfo>
        <AssemblyVersion>1.3.0.0</AssemblyVersion>
        <AssemblyVersion>1.4.0.0</AssemblyVersion>
        <AssemblyVersion>1.5.0.0</AssemblyVersion>
        <AssemblyVersion>2.0.0.0</AssemblyVersion>
      </AssemblyInfo>
      <ReturnValue>
        <ReturnType>System.Object</ReturnType>
      </ReturnValue>
      <Docs>
        <summary>Gets or sets the source of the binding.</summary>
        <value>An object used as the binding source.</value>
        <remarks>If the Source is not null, the BindingContext is ignored, and the Source is used instead. This allows to set a source for a single Binding, and not for all the Bindings applied to the BindableObject.</remarks>
      </Docs>
    </Member>
  </Members>
</Type>