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Default value for enum column

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This is a migrated thread and some comments may be shown as answers.
Richard
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Richard asked on 18 Nov 2014, 06:25 PM
Suppose I have an enum that I'd like to use in a Grid, using the _underlying value_ as the cell value:

public enum Currency : int {
   USD = 0,
   GBP = 1
}

The editor is thus something similar to:

@(Html.Kendo().DropDownListFor(m => m)
      .BindTo(Enum.GetValues(typeof(Currency)).Cast<Currency>().Select(v => {
          return new DropDownListItem()
          {
              Text = v.DisplayName(),
              Value = ((int)v).ToString(),
              Selected = v == Model,
          };
      }).ToList()))

If I don't include an entry in the data source model for the field, the field defaults as expected to 0.

However, if I include the following entry in the data source model, Kendo attempts to default the value to "usd":

model.Field(d => d.Currency).DefaultValue((int) Currency.USD);

This isn't a problem for this case, as I can just leave off the model configuration. However, it becomes a problem if I change the type of the column to Nullable<Currency> because there is no way to default the value to 0. Not configuring the model attempts to use null (which causes Kendo grid to throw an exception), and attempting to configure the model uses "usd", which is invalid.

I have attempted manually setting the schema using JS:

$(document).ready(function () {
     $("#MyGrid").data("kendoGrid").dataSource.options.schema.model.fields.Currency.defaultValue = 0;
}

However when I add a new column, the grid still attempts to use "usd" as the default value.

Please advise how to set the default value to 0 for a column type of Nullable<Currency>.



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Richard
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answered on 18 Nov 2014, 07:23 PM

As a work around, I've overwritten the _createNewModel method for the Grid.  

$(document).ready(function () { 
    // Kendo Hack to correct the default of currency to 0 (for USD)
      var gridSource = $("#MyGrid").data("kendoGrid").dataSource;
    gridSource.options.schema.model.fields.Currency.defaultValue = 0;
    gridSource._createNewModel = function (model) {
        if (this.reader.model) {
            var result = new this.reader.model(model);
            result.Currency = 0;
            return result;
        }
 
        if (model instanceof ObservableObject) {
            return model;
        }
 
        return new ObservableObject(model);
    };
});
0
Daniel
Telerik team
answered on 20 Nov 2014, 02:23 PM
Hello,

Could you clarify what exception is thrown when no default value is specified?
I reproduced the problem with the default value conversion and we will fix it for one of the next internal builds. For now I can suggest to set a function for the default value that returns the underlying value;
model.Field(o => o.Currency).DefaultValue(new Kendo.Mvc.ClientHandlerDescriptor
    {
        HandlerName = "function() {return " + (int)Currency.USD + "}"
    });

As for setting the value via JavaScript - this can be achieved as in the snippet below without overriding the dataSource methods:
$(document).ready(function () {
    $("#MyGrid").data("kendoGrid").dataSource.reader.model.fn.defaults.Currency = 0;
});


Regards,
Daniel
Telerik
 

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Daniel
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