skip to content »

www.140000.ru

Wpf combobox not updating when source updates

Updating after every keystroke can diminish performance and it denies the user the usual opportunity to backspace and fix typing errors before committing to the new value.

The default is Default, which returns the default Update Source Trigger value of the target dependency property.However, the default value for most dependency properties is Property Changed, while the Bindings that are Two Way or One Way To Source listen for changes in the target property and propagate them back to the source. Usually, these updates happen whenever the target property changes.This is fine for check boxes and other simple controls, but it is usually not appropriate for text fields.Deselectable Combo Box onclick if ( selected Item == current Target ), either throw a ctrl-click or just set selected Index = -1.A common requirement for any user interface application that accepts user input is to validate the entered information to ensure that it has the expected format and type for the back-end to be able to accept and persist it.Hmmm I never knew that you could ctrl-click on the combobox to reset that value to -1.

I knew about the pmrpot, but wow learn something new every day Sounds like that might be a nice custom control though.

The Mode property of the , which is the default for the Text property of the Text Box control, the text you type into the Text Box does not update the source property until the control loses focus which happens when you click away from it. the setter for the bound property of the Data Context to get called, as the user is typing into the Text Box you set the Update Source Trigger property to enumeration.

This is more precise and understandable to me to say that a ‘Delay’ property has been added to the Binding markup extension !

Correspondingly, an underlying data value in the view model is automatically updated when the user modifies the bound value in the view.

Provided that the view model has a property called “Name”, you bind it to a Text Box’s Text property in XAML the following way: Besides the path that specifies the name of the property to bind to, the binding must also have a source object.

This post is a part of the serie on WPF 4.5 new features.