[Solved] DataMemberBinding.Converter broken

[Patrick Holloway]

in Q2, this code worked fine, to format columnar data in $0.00 format:

GridViewDataColumn gvdc = (GridViewDataColumn)_dg.Columns[x];
    if (gvdc.DataMemberBinding.Converter == null) {
    gvdc.DataMemberBinding.Converter = new FloatToMoneyConverter();
}


public class FloatToMoneyConverter : IValueConverter {

   public object Convert( object value, Type targetType, object parameter, System.Globalization.CultureInfo culture ) {
      double val = System.Convert.ToDouble(value);
      string fval = String.Format("{0:C}", val);
      return fval;
}

   public object ConvertBack( object value, Type targetType, object parameter, System.Globalization.CultureInfo culture ) {
      return System.Convert.ToDouble(value);
   }
}

Now, with Q3, the converter is only applied when the cell is in Edit mode. Worse, it throws an exception when leaving the cell, because ConvertBack() is trying to convert a string of $0.00 format to a float. It seems completely backwards from what Q2 did.

If this is not a bug, what would be the correct way to implement this?

Thanks.

EDIT: I opened a support case for this, #261228, and sent along a sample project. Thanks 

[Rossen Hristov]

Hi Patrick Holloway,

1. You need to specify the IValueConverters before binding the grid, in the CreateColumn method. But I do not think you will be needing them at all. See the next points.

2 & 3. With Q3 we have made several changes. If there is an IValueConverter the edit mode will take it into account. That is it will use the converted value which would have to be converted back when editing finishes.

This means that if you decide to stick to converters you will have to rewrite your ConvertBack method to receive a string such as "$0.00" and return the double 0. But we have a better suggestion. If you are using this converter with the sole purpose of displaying currency, the the proper way to do this would be to use the column's DataFormatString property like this:

col.DataFormatString = "{0:C}";

This will have two benefits -- in edit mode you will see pure raw numbers (without the currency sign) and you will not have to implement a ConvertBack method that parses currency strings.

I have modified and attached the project. It is using our latest internal build binaries.

I hope this helps. Let me know if there are other issues.

Best wishes,
Ross
the Telerik team

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