Question

I am using Kendo UI to bind a datasource to the Kendo Grid. I am trying to find the best way to create a column in the grid that is not bound to the datasource.

Currently, I am creating a field in the datasource and using some javascript and jQuery to set the values of that column after the data is read from the remote endpoint.

Datasource:

schema: {
    model: {
        fields: {
            blah: {},
            empty_column: {}
        }
    }
}

Grid:

columns: {
    field: "empty_column",
    width: 100,
    title: "Empty"
}

Javascript:

datasource.data[item].set("empty_column", computed_value);

All code edited for brevity, it all works fine.

My question: is there a way to set the defaultValue for this new, empty column which is not connected to the remote endpoint?
When I set:

empty_column: {defaultValue: "None"}

the grid still displays ‘undefined’, I think because it is not receiveing any data for that field in the read operation. Is there a way to set the defaultValue in the grid? I haven’t seen any examples of this…

Answer 1

defaultValue applies when you create a record, not when it is going to be displayed.

You can do:

Option 1: use parse in schema.fields.fieldName that would be something like this.

model: {
    fields: {
        empty_column: {
            type        : "string",
            defaultValue: "none",
            parse       : function (data) {
                if (!data.empty_columns) {
                    data.empty_column = "none";
                }
                return data;
            }
        },
        blah        : { type: "number" }
    }
},

Option 2: Use schema.parse for adding the extra field value.

            schema: {
                model: {
                    fields: {
                        empty_column: {type: "string", defaultValue: "none"},
                        blah        : { type: "number" }
                    }
                },
                parse: function (response) {
                    $.each(response, function (idx, item) {
                        if (!item.empty_column) {
                            item.empty_column = "none";
                        }
                    });
                    return response;
                }
            }

Of course, (for both options) if you certainly know that there is no previous value in empty_column you might save the test condition and leave only the assignment.