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How to: Detect When Text in a TextBox Has Changed
03/30/2017
csharp
vb
TextBox control [WPF], detecting text change
text change [WPF], detecting
detecting text change [WPF]
1c39ee14-e37f-49fb-a0d1-a9824ca13584

How to: Detect When Text in a TextBox Has Changed

This example shows one way to use the xref:System.Windows.Controls.Primitives.TextBoxBase.TextChanged event to execute a method whenever the text in a xref:System.Windows.Controls.TextBox control has changed.

In the code-behind class for the [!INCLUDETLA2#tla_xaml] that contains the xref:System.Windows.Controls.TextBox control that you want to monitor for changes, insert a method to call whenever the xref:System.Windows.Controls.Primitives.TextBoxBase.TextChanged event fires. This method must have a signature that matches what is expected by the xref:System.Windows.Controls.TextChangedEventHandler delegate.

The event handler is called whenever the contents of the xref:System.Windows.Controls.TextBox control are changed, either by a user or programmatically.

Note: This event fires when the xref:System.Windows.Controls.TextBox control is created and initially populated with text.

Example

In the [!INCLUDETLA#tla_xaml] that defines your xref:System.Windows.Controls.TextBox control, specify the xref:System.Windows.Controls.Primitives.TextBoxBase.TextChanged attribute with a value that matches the event handler method name.

[!code-xamlTextBox_MiscCode#_TextChangedXAML]

Example

In the code-behind class for the [!INCLUDETLA2#tla_xaml] that contains the xref:System.Windows.Controls.TextBox control that you want to monitor for changes, insert a method to call whenever the xref:System.Windows.Controls.Primitives.TextBoxBase.TextChanged event fires. This method must have a signature that matches what is expected by the xref:System.Windows.Controls.TextChangedEventHandler delegate.

[!code-csharpTextBox_MiscCode#_TextChangedEventHandler] [!code-vbTextBox_MiscCode#_TextChangedEventHandler]

The event handler is called whenever the contents of the xref:System.Windows.Controls.TextBox control are changed, either by a user or programmatically.

Note: This event fires when the xref:System.Windows.Controls.TextBox control is created and initially populated with text.

Comments

See Also

xref:System.Windows.Controls.TextChangedEventArgs
TextBox Overview
RichTextBox Overview