I have a general question about the context of callback functions:
I have, for example, in an arbitrary class a model which I want to modify
with different textboxes, for that I have defined a
converter function because I want to deal with numbers instead of strings:
tf.bind("value", model, tar, {
converter : function(value) { return (parseFloat(value));
}
});
but now I want to handle language specific number conversion, therefore I
have a member function of a class which depends on a
property of that object (mainUI.StringToNumber(value)), therefor I need a
this-reference in the converter, but there is no 'this'
defined
tf.bind("value", model, tar, {
converter : function(value) { return
this.mainUI.StringToNumber(value);
//ERROR: this not defined }
});
One solution might be to define a Javascript variable which holds the
object:
var tf = new qx.ui.form.TextField();
var objMainUI = this.mainUI;
tf.bind("value", model, tar, {
converter : function(value) {
return objMainUI.StringToNumber(value);
}
});
But this solution is looking a little bit weird.
Is there a possibility to pass the this-reference to the callback function?
Another question is:
I have a button, in that execute listener I want to call a callback function
which is defined in another class, and in that callback-
function I want to use the this-reference of the same class, how can I do
that?
For example:
qx.Class.define("proj.Statics",
{
extend: qx.core.Object,
include : [qx.locale.MTranslation],
statics :
{
showConfirmationDialog: function(type, message,
callback)
{
//......
var button = new qx.ui.form.Button();
button.addListener("execute", function(e)
{
callback();
}, this);
}
}
}
);
qx.Class.define("proj.MainUI",
{
extend: qx.core.Object,
members :
{
test : function(applicationRoot)
{
upa.Statics.showConfirmationDialog(upa.Statics.CONFIRMATION_DIALOG_TYPE_INFO,
"Test" , function(e)
{
//
-----------------------------------------------------???????????????????????????????
//here I want to use 'this' (Rererence of the
object of 'proj.MainUI')
});
}
}
});
Are there any ideas how to achieve this?
Thank you very much!
Regards,
Hans Juergen
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