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DatePicker week number silverlight

Can i enable week number in silverlight DatePicker ? And how ?

That is not possible with the standard DatePicker control, have you considered adding another control like a label and when the user clicks the date you display the week in the label.
ScreenShot

Stop DatePicker from resetting the TimeOffDay when new date is selected

I have a DatePicker which displays the date only and a separate TextBox that displays the time. Both elements use TwoWay binding.
My issue is that when ever I adjust the date using the DatePicker, my time resets to 00:00. Is there a way to disable this behavior and leave the TimeOfDay alone? I can't seem to find an answer anywhere.
I know I could grab the time with a GotFocus event and then manually restore, but it seems messy.

The DatePicker and TextBox should be bound to two different source properties, a DateTime? and a TimeSpan respectively.
The built-in DatePicker control selects only a date without any specific time so it makes no sense to try to display the time of the selected date in a TextBox.

How to set ClockIdentifier dynamically in WinRT app

I have a TimePicker and would like to set its ClockIdentifier property dynamically based on the time format supported by the locale of that system. I tried getting the CultureInfo.CurrentUICulture.DateTimeFormat, but, it does not have any property specifying whether current culture set on the system supports 12 hour time format or 24 hours format.
Any ideas?

How to programatically dismiss the calendar of a DateTimePicker

I am working on a Windows Form that uses a good amount of DateTimePicker controls.
As per spec, the controllers need to show 'no date' initially till user manually selects a date.
As per the DateTimePicker functionality, we cant assign 'nothing' as a value.
So what we do is set a default minimum date, and then change the custom format of the control to "", to give the illusion of an empty field.
A quirk we have found is that when the user clicks on the DateTimePicker and selects a new date for the first time, his initial click does not dismiss the calendar. So instead the calendar persists, and the user has to manually click outside the control to dismiss the calendar.
To make the user experience slightly worse, while in this state the calendar is immune to any further date selection. So the date selection is stuck with the initially selected date, and the user needs to click out.
Once a date has been selected by the control, selecting a new date dismisses the calendar as expected.
My best guess would be that it would have something to do with the custom format that is there originally, which causes a hiccup with the control when a new properly formatted date is selected.
I am trying to find a way to 'force' the calendar to dismiss if open on value change, but I am not finding the way to do this.
I have even tried to set focus elsewhere on value change, but no luck either.
Has anybody else experienced this behavior and/or know of a way around it?
Thanks!
Some of the code-----------
//if dateTime property has not been saved, then call ClearDateTime on the controller, else display the saved value.
public static void ClearDateTime(DateTimePicker dtp)
{
dtp.Value = DateTime.Today.AddDays(-1);
//set the format
dtp.Format = System.Windows.Forms.DateTimePickerFormat.Custom;
// set custom format to empty
dtp.CustomFormat = " " ;
}
// When value is changed/date is selected
private void DateTimePicker_ValueChanged(object sender, EventArgs e)
{
MainFormUtilities.ShowDateTime(this.DateTimePicker);
this.LockFormDown();
}
public static void ShowDateTime(DateTimePicker dtp)
{
dtp.Format = System.Windows.Forms.DateTimePickerFormat.Long;
}

Essentially you need to manually raise the CloseUp event, please refer to the solutions here, How can I programmatically close the dropdown calendar of a datetimepicker or update the dropdown calendar to reflect the .Value property?.

I had a similar situation where a client insisted on having the field show no date (appear blank). I gave up on trying to hack the standard .NET DateTimePicker and used the DevExpress DateEdit control which does allow a blank value.

The solution I have pursued that was most practical for my project was the suggestion by Reniuz, to use a checkbox to control the values and behaviour of the DateTimePicker.
If a user wants to add a date, he selects the checkbox which enables the Picker and defaults to todays date.
If he wants to clear the date (ie not submit a date after all) he unchecks the checkbox which clears the picker with a empty format and we save nothing to the database.
If I had the points I would upvote all the other suggestions. They were helpful, but this solution seemed to be the practical path for us. Thanks to all again!

DateTime Picker In WinForm How To Pick Time? [duplicate]

This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
DateTimePicker: pick both date and time
I'm using a WinForm DateTime picker and it does a fantastic job of choosing dates, but I don't know how to do times. It looks like a time is associated with the value, so maybe there's a way to use this to pick a time?
If there is no built in way to do this, I'll just create another box for the time and modify the DateTime value from the DateTime picker.
Thanks!

You can use the built in DateTime picker by adding a custom format string as follows:
DateTimePicker.ShowUpDown = true;
DateTimePicker.CustomFormat = "hh:mm";
DateTimePicker.Format = System.Windows.Forms.DateTimePickerFormat.Custom;
Enjoy!

You can either choose the datepicker to have a "long" date, even only "time" or you can create your custom date.
I always use this format, as it's the most easy one to understand for users (IMHO): yyyy.MM.dd HH:mm
This can be done in the designer the fastest, just change the property.
Or, change it in the program with
YourDatePicker.Format = DateTimePickerFormat.Custom;
YourDatePicker.CustomFormat = "yyyy.MM.dd HH:mm";

The DateTimePicker works pretty much like how setting the Windows clock works. If you set the ShowUpDown property to true, it displays a spin control to the right of the DateTimePicker. If you then click on a section of the control, such as the time in hours, and then hit the up or down arrow of the spin control, it will change the time in hours.
Also, if you want to use a custom DateTime format, change the Format property to Custom and set the flags you'd like. For example, MM dddd yyyy HH:mm:ss. For an explanation of all the custom format specifiers, here's the full list of them from MSDN.
Hope that helps.