Filter Empty Date Value

[Betsy]

 I have a GridView with a Nullable(DateTime) column (Inactive Date).  I want the grid to open with a default filter of records where the InactiveDate has no value.  How can I do this?  I have tried something like below but keep getting an error that String cannot be converted to a DateTime value.  I've tried Value="", Value=" ", Value="Nothing"....can't get it to work.

<telerik:RadGridView ItemsSource="{Binding Items}" AutoGenerateColumns="False" Name="datagrid" DataLoaded="datagrid_DataLoaded" >
  <telerik:RadGridView.FilterDescriptors>
    <telerik:FilterDescriptor Member="InActiveDate" Operator="IsEqualTo" Value=" " />
  </telerik:RadGridView.FilterDescriptors>
  <telerik:RadGridView.Columns>
    <telerik:GridViewDataColumn Header="Device Number" DataMemberBinding="{Binding DeviceNumber}" ShowDistinctFilters="False" />
    <telerik:GridViewDataColumn Header="Active Date" DataMemberBinding="{Binding ActiveDate}" DataFormatString="{}{0:d}" Width="90" />
    <telerik:GridViewDataColumn Header="InActive Date" DataMemberBinding="{Binding InActiveDate}" ShowDistinctFilters="False"  DataFormatString="{}{0:d}" Width="90"/>
    <telerik:GridViewDataColumn Header="Service Account" DataMemberBinding="{Binding IssuingAccountName}" />
    <telerik:GridViewDataColumn Header="License Plate" DataMemberBinding="{Binding VehicleLicensePlate,TargetNullValue=Not Assigned}" ShowDistinctFilters="False" />
    <telerik:GridViewDataColumn Header="Truck Number" DataMemberBinding="{Binding VehicleDisplayName}" ShowDistinctFilters="False"  />
  </telerik:RadGridView.Columns>
</telerik:RadGridView>

[Veselin Vasilev]

Hello Heather,

You can try the following:

<telerik:FilterDescriptor Member="InActiveDate" Operator="IsEqualTo" Value="{x:Null}" />

Kind regards,
Veselin Vasilev
the Telerik team

[Betsy]

Wonderful, thank you.  Is there any way to make the Filter icon show that it has a filter?

[Veselin Vasilev]

Hello Heather,

To make that work you need to use the ColumnFilterDescriptor. It should be created in code behind only.

Hope this helps.

Best wishes,
Veselin Vasilev
the Telerik team

[Betsy]

OK, so I changed things to create the filter in code as follows in the UserControl loaded event.

Dim columnDescriptor As New ColumnFilterDescriptor(DirectCast(vehiclegrid.Columns("InActiveDate"), IDataFieldDescriptor))
columnDescriptor.FieldFilter.Filter1.Operator = FilterOperator.IsEqualTo
columnDescriptor.FieldFilter.Filter1.Value = Nothing
vehiclegrid.FilterDescriptors.Add(columnDescriptor)

This works great but if I try to change the filter from the UI I get the following error and the filter does not change.  The InActiveDate column is of type Nullable(Of DateTime)

System.Windows.Data Error: 23 : Cannot convert '' from type 'FilterDescriptorUnsetValue' to type 'System.Nullable`1[System.DateTime]' for 'en-US' culture with default conversions; consider using Converter property of Binding. NotSupportedException:'System.NotSupportedException: DateTimeConverter cannot convert from Telerik.Windows.Data.FilterDescriptor+FilterDescriptorUnsetValue.
   at System.ComponentModel.TypeConverter.GetConvertFromException(Object value)
   at System.ComponentModel.TypeConverter.ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, Object value)
   at System.ComponentModel.DateTimeConverter.ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, Object value)
   at System.ComponentModel.NullableConverter.ConvertFrom(ITypeDescriptorContext context, CultureInfo culture, Object value)
   at MS.Internal.Data.DefaultValueConverter.ConvertHelper(Object o, Type destinationType, DependencyObject targetElement, CultureInfo culture, Boolean isForward)'

[Veselin Vasilev]

Hello Heather,

I tried to reproduce the problem in a simple project but everything worked as expected - no exception was thrown. Can you please open a support ticket and attach a sample project there so we can investigate it more thoroughly.

Regards,
Veselin Vasilev
the Telerik team