RadDataForm: Get the Result

If you followed the articles about providing the source and describing the properties, you now know how to edit an object's properties with RadDataForm for NativeScript. Now to get the result of these modifications, you need to commit the modifications and get the updated object.

Commit Changes

When you set the source property of RadDataForm, an editor is created for each of the properties of the source object and the values of these properties are loaded into the corresponding editor. When you make changes to the values of the editors, they are not necessarily immediately saved in the source object. The changes are saved when the values are validated (if there are validators) and then committed. To commit a value in the context of RadDataForm means to save the current editor value in the source object. When this commit happens is determined by the value of the commitMode property.

Commit Modes

The commit modes in RadDataForm define when the changes in the editors will be reflected in the source object. You can set your preferred value to the commitMode property. Here are the options:

  • Immediate: This is the default mode. All changes are committed immediately when the editor's value is changed.
  • OnLostFocus: The changes are committed when another editor gets focused.
  • Manual: The changes are committed only when the commitAll or the validateAndCommitAll methods is called.

Once the modifications are committed the source object will be updated so you can use it to check the result. You can also use the editedObject property of RadDataForm which returns a stringified JSON representation of the modified object.
When the commit is Manual, the commit happens when one of the commitAll or validateAndCommitAll methods is called. The first is of type void while the second returns a Promise which will be resolved with a boolean value which is the result from the validation. When there is no validation, the two methods do not differ significantly. When there is validation, you need to ensure that the values are validated before calling commitAll or you can use validateAndCommitAll which will do the both. You can read more about the validation in RadDataForm here.

Commit Events

RadDataForm provides propertyCommit and propertyCommitted events that you can use to get notified that some modifications are committed or are about to be.
The propertyCommit event notifies you before the actual commit so you can optionally cancel it by setting the returnValue of the arguments to false as shown in the following example.

Example 1: Cancel the commit for an editor

<RadDataForm [source]="person" marginTop="50" row="1" (groupExpanded)="dfGroupExpanded($event)" (groupCollapsed)="dfGroupCollapsed($event)"
    (propertyCommit)="dfPropertyCommit($event)" (propertyCommitted)="dfPropertyCommitted($event)">
public dfPropertyCommit(args) {
    if (args.propertyName == "name") {
        this._eventsText = "LastEvent: name property commit cancelled";
        args.returnValue = false;
    }
}

The other event - propertyCommitted - is called after the property is committed so you can use it to get the new value from the source object or through the RadDataForm's editedObject property.

References

Want to see these scenarios in action?
Check our SDK Examples for Angular repo on GitHub. You will find these and many other practical examples with NativeScript UI.

Related articles you might find useful: