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Binding to date on new object shows DateTime.MinValue. Can this be hidden?

I've got a DatePicker field that's bound to an underlying object. When I create a new object and bind it to the screen, it displays DateTime.MinValue (1/1/0001), which is expected. But, I don't want the user to see that, I want them to see an empty text-box.

How can I accomplish this?

Thanks,
Chris

CCusson15

You can do an IValueConverter to handle this and put this converter in the binding. For example:

public class DateTimeNullConverter : IValueConverter
{
 public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
 {
  if (value is DateTime)
  {
   DateTime typedValue = (DateTime)value;
   if (typedValue == DateTime.MinValue)
   {
    return string.Empty;
   }
   return typedValue.ToString();
  }
  throw new InvalidOperationException();
 }

Marked As Answer byJim Zhou - MSFTModeratorMonday, April 13, 2009 9:49 AM

Mariano O. Rodriguez

Hi CCussson15,
I have answered a similar question here http://social.msdn.microsoft.com/Forums/en-US/wpf/thread/b3c600cc-c848-4733-b193-9c2c39db7ae5

The answer is about the same. although the converter would be different:

The easiest way to me is to use a converter, taking in a DateTime, returning a string.
In converter:
1. Cast value to DateTime.
2. Compare to DateTime.MinValue
3. If true return string.Empty, if not DateTime.toString()

Hope this helps!

-noorbakhsh

Marked As Answer byJim Zhou - MSFTModeratorMonday, April 13, 2009 9:49 AM
Proposed As Answer bynoorbakhsh Friday, April 10, 2009 4:18 PM

noorbakhsh

You can do an IValueConverter to handle this and put this converter in the binding. For example:

public class DateTimeNullConverter : IValueConverter
{
 public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
 {
  if (value is DateTime)
  {
   DateTime typedValue = (DateTime)value;
   if (typedValue == DateTime.MinValue)
   {
    return string.Empty;
   }
   return typedValue.ToString();
  }
  throw new InvalidOperationException();
 }

Marked As Answer byJim Zhou - MSFTModeratorMonday, April 13, 2009 9:49 AM

Mariano O. Rodriguez

Marked As Answer byJim Zhou - MSFTModeratorMonday, April 13, 2009 9:49 AM
Proposed As Answer bynoorbakhsh Friday, April 10, 2009 4:18 PM

noorbakhsh

Thanks noorbakhsh and Mariano, this works great!!

One question, what should i put in for the ConvertBack method? I'm thinking this isn't something I need to do (though I need to code it bc of the interface).

Thanks,
Chris

CCusson15

If you are using TwoWay mode you will need to implement this method too. Basically you have to convert from string to DateTime.

Mariano O. Rodriguez

You could make the datetime object nullable.

mariocatch

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