Check WPF Selection Date

Question

How to apply validations to a WPF datepicker toolbox? I want him to make a mistake if the wrong date is selected, and in some cases I have arrival and departure dates, so I want to check it to see that the arrival date is not later than the departure date.

Answer 1

It seems the year above the validation of the date picker has a problem . Anyway, now it works.

I'm not a WPF specialist, boo, I will try to give you an idea

write a validation rule

public class DateExpiredRule : ValidationRule { public override ValidationResult Validate(object value, CultureInfo cultureInfo) { DateTime orderDate = (DateTime)value; return new ValidationResult(orderDate < DateTime.Now, "Please, enter date before Now()"); } } 

then you can attach it to datepicker

  <!-- since validation works hand by hand with binding, I use hidden datepicker as binding source --> <WPFToolkit:DatePicker Name="dateProvider" Visibility="Collapsed"> </WPFToolkit:DatePicker> <WPFToolkit:DatePicker Name="notExpired"> <WPFToolkit:DatePicker.SelectedDate> <Binding ElementName="dateProvider" Path="SelectedDate" UpdateSourceTrigger="PropertyChanged"> <Binding.ValidationRules> <local:DateExpiredRule/> </Binding.ValidationRules> </Binding> </WPFToolkit:DatePicker.SelectedDate> </WPFToolkit:DatePicker> 

specify the management template for validation failure. By default, a validation error changes the border color. I used an extra hint when the mouse is under control.

source

About the statement "picker for picking."

I know that you can use custom properties in validation rules (see AgeRangeRule in msdn )

Maybe you should use this feature like

 <local:MaxDateRule MaxDate="{Binding ElementName=DepartureDatePicker, Path=SelectedDate" /> 

but in order to apply the binding, you need to make MaxDate a dependent property. You should definitely ask the guru;)

Instead of highlighting, you should consider intercepting the change in the date picker value (through some datepicker onchange event) and accept or reject the change.