Enable Button When One Of Many Controls Is Changed
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I have a Textbox, CheckBox, NumericUpDown, and Button on my form.
The button's Enabled Property is set to False and this button is a Save Button.
The data for the textbox, checkbox, and numericupdown is loaded from a textfile.
My question is this....
After the data is read from the file and the textbox and numericupdown has its data, and the checkbox is either set to True or False, can I group these 3 controls into a collection or some other grouping and when any one of them is changed, the save button's Enabled property is set to True.
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No, there is no "official" way to do it. You can handle all its events by calling some save sub, which will button.PerformClick, or, if you plan to behave such manner in wider range in project, you can easily create some class, which, for example inherited from arraylist, will for every Overrides Sub Add(control) assign handler (e.g. AddHandler control.TextChanged, AddressOf Me.TextBoxes_TextChanged) depending on control.gettype.lowestbasetype (or just type, if you are not creating some extra controls with inheriting). This inherited collection will then have Public Event ValueChanged(sender as object, field as control) which will be Raised in all such event handlers.
Pseudo sample:
Class evtCollectorInherits ArrayList
Public Event ValueChanged(Sender, Field)
Private Sub TextBoxes_TextChanged(sender As Object, args As ...) ---HANDLER
RaiseEvent ValueChanged(Me, sender)
End Sub...another HANDLERS for different controls you use
Public Overrides Function Add(c as control) As Integer
If c.GetType.Equals(TextBox)
AddHandler c.TextChanged, AddressOf Me.TextBoxes_TextChanged
Else
AddHandler c.ValueChanged, AddressOf Me.NumericUDs_ValueChanged
..
MyBase.Add(c)
End FunctionAfter such implementation you simply create Withevents group1, group2 ... As evtCollector
and in sub new of form you fill them... and handle its event -
figured this one out as soon as you pointed out the handlers to me
Private SaveControlData ( )
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figured this one out as soon as you pointed out the handlers to me
Private SaveControlData ( )
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figured this one out as soon as you pointed out the handlers to me
Private SaveControlData ( ) Handles
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figured this one out as soon as you pointed out the handlers to me
Private SaveControlData ( ) Handles Textbox1.TextChanged, Checkbox1.CheckState, _
NumericUpDown.ValueChanged
Button1.Enabled = True
End Sub
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poetic solution
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