Mutliselect Text return null reference exception

[shang]

I am enabling mulitpleselection of combobox and using Text field to bind a string value. After I use the multipleSelectionSeparator = "|", there is the null reference exception thrown. The binding field "BindText" has been initialized to empty string. There is no issue if I do not use multipleSelectionSeparator., so I am really confused why null reference is thrown and stack trace image is attached.

<telerik:RadComboBox x:Name="RadComboBox"                             

 IsReadOnly="False"                             

 IsEditable="False"                              

Text="{Binding BindText, Mode=OneWayToSource}"                             

 AllowMultipleSelection="True"                        

ItemsSource="{Binding BindTexts}"                             

 IsEnabled="{Binding IsEnabled}"                                

MultipleSelectionSeparator=";"         

/>

[Martin Ivanov]

Hello Shang Sun,

The error appears because the control expects that the Text property won't contain null value in the multiselection scenario. However, it seems that initially the binding returns a null value which messes up with the initial selection logic. To avoid the error you can set the FallbackValue property of the binding to an empty string. Here is an example in code:

<telerik:RadComboBox Text="{Binding Text, Mode=OneWayToSource, FallbackValue={x:Static system:String.Empty}}"/>

Where "system" points to "xmlns:system="clr-namespace:System;assembly=mscorlib"".

I hope that helps.

Regards,
Martin Ivanov
Progress Telerik