Populate another Datasource from within first!

[Bilal]

Hi,
I have a view model with two Data Sources A & B.

- Data Source A requests data from server. Data received contains multi-collections.
- One collection is returned from the "Parse" function to populate Data Source A
- Another collection is being set to a JavaScript variable to be used later on by Data Source B. Why? I couldn't access current view model to set the value of the other Data Source.

Problem now is, when the page loads, the local collection is empty and Data Source B is defined based on that local collection. By the time the data received by Data Source A, the form would have been bound to empty data.

Is there a work around in here?

signatures is a local array outside view model that is being updated by Data Source A parse function.

signatureDatasource: new kendo.data.DataSource({
    data: function() { return signatures },
    schema: {
        model: SignatureModel
    }
})

[Sherman]

Can you not use a promise from datasource A to then update datasource B?

$(function() {
    datasourceA.read().then(function() {

        datasourceB.read();

    });
});

[Petyo]

Hello,

Problem now is, when the page loads, the local collection is empty and Data Source B is defined based on that local collection. By the time the data received by Data Source A, the form would have been bound to empty data.

If I understand you correctly, you are trying to avoid that behavior. Can you please elaborate on the alternative which would fit your project requirements? Thank you in advance.

Regards,
Petyo
Telerik

 

 

[Bilal]

Hi Petyo,

I might be "misusing" the Data Source in a sense that I am returning multiple sets of data from server. However, in the parse function I return whatever data needed by Data Source to bind to Grid. The rest I am currently populating them as follows:

if ( e.signatures ) {
    viewmodel.get("signatureDatasource").data(e.signatures);
}

At first the "signatureDatasource" is empty, but then it gets populated.

The aforementioned Data Source is used to populate a Drop Down List, so it is not major and essential to be shown when page loads.

How do you find this solution?

Best regards
Bilal Haidar

[Petyo]

Hello Bilal,

in case this solution is applicable to your project, feel free to implement it. 

Regards,
Petyo
Telerik