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33 lines
3.1 KiB
Markdown
33 lines
3.1 KiB
Markdown
---
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title: "How to: Bind to a Method"
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description: Follow this example to find out how to bind to the method of an object in the Windows Presentation Foundation (WPF).
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ms.date: "03/30/2017"
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helpviewer_keywords:
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- "data binding [WPF], binding to methods using ObjectDataProvider"
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- "binding [WPF], to methods"
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- "methods [WPF], binding to"
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ms.assetid: 5f55e71e-2182-42a0-88d1-700cc1427a7a
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---
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# How to: Bind to a Method
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The following example shows how to bind to a method using <xref:System.Windows.Data.ObjectDataProvider>.
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## Example
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In this example, `TemperatureScale` is a class that has a method `ConvertTemp`, which takes two parameters (one of `double` and one of the `enum` type `TempType)` and converts the given value from one temperature scale to another. In the following example, an <xref:System.Windows.Data.ObjectDataProvider> is used to instantiate the `TemperatureScale` object. The `ConvertTemp` method is called with two specified parameters.
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[!code-xaml[BindToMethod#WindowResources](~/samples/snippets/csharp/VS_Snippets_Wpf/BindToMethod/CS/Window1.xaml#windowresources)]
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Now that the method is available as a resource, you can bind to its results. In the following example, the <xref:System.Windows.Controls.TextBox.Text%2A> property of the <xref:System.Windows.Controls.TextBox> and the <xref:System.Windows.Controls.Primitives.Selector.SelectedValue%2A> of the <xref:System.Windows.Controls.ComboBox> are bound to the two parameters of the method. This allows users to specify the temperature to convert and the temperature scale to convert from. Note that <xref:System.Windows.Data.Binding.BindsDirectlyToSource%2A> is set to `true` because we are binding to the <xref:System.Windows.Data.ObjectDataProvider.MethodParameters%2A> property of the <xref:System.Windows.Data.ObjectDataProvider> instance and not properties of the object wrapped by the <xref:System.Windows.Data.ObjectDataProvider> (the `TemperatureScale` object).
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The <xref:System.Windows.Controls.ContentControl.Content%2A> of the last <xref:System.Windows.Controls.Label> updates when the user modifies the content of the <xref:System.Windows.Controls.TextBox> or the selection of the <xref:System.Windows.Controls.ComboBox>.
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[!code-xaml[BindToMethod#UI](~/samples/snippets/csharp/VS_Snippets_Wpf/BindToMethod/CS/Window1.xaml#ui)]
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The converter `DoubleToString` takes a double and turns it into a string in the <xref:System.Windows.Data.IValueConverter.Convert%2A> direction (from the binding source to binding target, which is the <xref:System.Windows.Controls.TextBox.Text%2A> property) and converts a `string` to a `double` in the <xref:System.Windows.Data.IValueConverter.ConvertBack%2A> direction.
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The `InvalidationCharacterRule` is a <xref:System.Windows.Controls.ValidationRule> that checks for invalid characters. The default error template, which is a red border around the <xref:System.Windows.Controls.TextBox>, appears to notify users when the input value is not a double value.
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## See also
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- [How-to Topics](data-binding-how-to-topics.md)
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- [Bind to an Enumeration](how-to-bind-to-an-enumeration.md)
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