Dynamic GridViewColumns filter function throw exception

[Michael]

I have a GridView where the GridViewColumns are created dynamically. We now have data in a column that can sometimes be null. I have kind of figured out how to use the Converter from the binding to change the value based on the value coming in - but this did not fix it. When I click on the filter It throws the error that must be of type Int64.

Here is the code that builds the column:

GridViewDataColumn col = new GridViewDataColumn();
                col.Header = column.Name;
                col.DataMemberBinding = binding;
                col.DataType = column.DataType;
                col.IsSortable = true;

                if (column.DataType == typeof(Int64))
                {
                    col.DataMemberBinding.Converter = new LongConverter();
                }

 Here is the converter: 

public class LongConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            //Int64? convertedValue = (Int64)value;
            //if (convertedValue.HasValue)
            //{
            //    return convertedValue.Value;
            //}
            //else
            //{
            //    return "";
            //}

            return "N/A";
        }

        public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            if (value.ToString().ToUpper() == string.Empty)
            {
                return new Int64();
            }
            else
            {
                return Int64.Parse(value.ToString());
            }
        }
    }

You can see I commented all most of the code out on the converter. I was just trying to get it to work. The value was coming back as the type - so I'm not sure whats going on there.

So I really have to issues here:
1) How to properly set the converter on the column datamember binding.
2) Why does the filter still recognize the null value even though I set the value to "N/A"

[Dimitrina]

Hello,

You get an exception as you try to cast the "N/A" string to an Int64 value. Please make sure that you convert only valid values.

Regards,
Didie
Telerik