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Nullable DateTimePicker

Printed From: IdeaBlade
Category: DevForce
Forum Name: DevForce Classic
Forum Discription: For .NET 2.0
URL: http://www.ideablade.com/forum/forum_posts.asp?TID=502
Printed Date: 25-Apr-2025 at 12:44am


Topic: Nullable DateTimePicker
Posted By: Miszou
Subject: Nullable DateTimePicker
Date Posted: 16-Oct-2007 at 11:05am
I am trying to databind a nullable DateTime to the DateTimePicker in .NET.
 
However, it does not appear to be working as I would expect - and I'm not sure if this is due to the 3rd party DateTimePicker controls I am using, or whether the DateConverter is somehow translating the data prior to display.
 
I have tried several free controls that I have found on the internet, but none of them seem to work properly when binding to an EntityList<T>. I am particularly interested in using this one http://www.codeproject.com/cs/miscctrl/NullableDateTimePicker.asp - http://www.codeproject.com/cs/miscctrl/NullableDateTimePicker.asp  as I like the display when there is no date. (a prompt string instead of an unchecked checkbox and todays date).
 
I realize that you probably aren't going to support this guys control (!), but I was wondering if you could perhaps point me in the right direction. I am wondering whether I have to create my own DataConverter to support null values? And if so, would you happen to have a DateConverter that supports null values just sort of lying around? Wink
 
Basically, do I need to write my own DevForce specific DateTimePicker and/or DateConverter to get it to work as I want?
 
Thanks for your help.


Replies:
Posted By: davidklitzke
Date Posted: 16-Oct-2007 at 7:50pm

I am not entirely sure why you don't want to use the DevForce Nullable Date Picker.  I assume that you don't like the way it looks when the date is Null.

Here are some options:

(1) You might consider building a custom control based on the Nullable Date Picker.  Look at a previous post and the reply at:
 
http://www.ideablade.com/forum/forum_posts.asp?TID=133 - http://www.ideablade.com/forum/forum_posts.asp?TID=133
 
It shows you how to create a custom control (a textbox with a blue background).  This custom TextBox will show up in the Designer and will be one of your choices for a TextBox control in your Autopopulate form.

I can give you the DataBinder for the NullableDataPicker.

(2) Use .NET databinding

You can use .NET databinding to bind to DevForce objects

Posted By: Miszou
Date Posted: 17-Oct-2007 at 9:05am

Thanks for your quick reply.

Yes, the reason for using a different nullable date-time picker is due to a customer requirement that no date should be displayed if no date has yet been entered. The .NET date-time picker (is this the same as the DevForce one?) will always display a date, even when the value is null.
 
It has a strange checkbox implementation that is not intuitive at all - especially as null dates are displayed as todays date, but grayed out.
 
So, what I would really like, is a datetime picker that allows users to type freehand dates, but also contains a drop down picker. I was hoping to be able to use the control that I mentioned in my initial post, but I don't think it's going to work...
 
I think I am going to have to write my own control (using http://www.ideablade.com/forum/forum_posts.asp?TID=133 - http://www.ideablade.com/forum/forum_posts.asp?TID=133  as a reference).
 
As far as I can see, there are a couple of ways to go about this. I can either create an owner-drawn date-time picker, or I can roll my own, using a combination of a combo-box and a calendar control, which is the direction I am leaning towards at the moment. I can catch the dropdown/up events and display the calendar appropriately and users can also type free text into the combo (which would of course be parsed by a DateConverter).
 
At some point, I will almost certainly need to host this control in a DataGridView as well, but I am assuming I can follow these instructions to implement that functionality: http://msdn2.microsoft.com/en-us/library/7tas5c80%28VS.80%29.aspx - http://msdn2.microsoft.com/en-us/library/7tas5c80(VS.80).aspx  
 
You also mentioned that you could give me the DataBinder for the NullableDatePicker. If you could provide that, or even just an example of a custom DataBinder, I would be extremely grateful.
 
Thanks again for your response, and if you think of any additional hints or pitfalls to avoid, please let me know!

Posted By: Customer
Date Posted: 17-Oct-2007 at 10:12am
See the post I last referenced (about the custom blue textbox control) to see an example of how to build a custom binder.

Posted By: dr_kreso
Date Posted: 04-Jan-2010 at 12:39pm
1. Bind your datetimepicker.text, not datetimepicker.value
2. Add this code in datetimepicker_Validating(object sender, CancelEventArgs e) event:

if (!datetimepicker.Checked)
((Order)orderBindingSource.Current).OrderDate= null;

So, you need to manually set your Date to null value

3. ShowCheckBow of datetimepicker must be set to True

I hope it helps!


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