How can I check the contents before leaving the userControl?

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Hi,
I have built a WPF-UserControl that is to accept a date value. For the control is equipped with 3 TextBoxes. For day, month and year.
When the user enters a number for the day, the entered value is checked for logical validity about the event "TextBox_PreviewLostKeyboardFocus". (Only not > 31).
If the value is valid, then the focus is automatically shifted to the TextBox for the month. Is the value not valid, then forwarding the focus will be canceled and selects the specified value. The same procedure for the month (only not > 12). After entering the value for Year, the Inputs are checked for Leapyear (February 29, 2000 = o.k, 2001 = wrong). The user must Change the input.

If the control is left by the user, then about the event "Control_PreviewLostKeyboardFocus" the inputs are checked for a valid date. Are all TextBoxes empty, this ist o.k. too. This case must be checked by the application which uses my UserControl.

And now the Problem:
The event "Control_PreviewLostKeyboardFocus" is raised first by any TextBoxFocus change.

Is it possible to manipulate the raising of "Control_PreviewLostKeyboardFocus"? Or is there an other way to check the Input?

Thanks in advance.

Posted 8-Apr-15 0:13am

oldboy24

Updated 8-Apr-15 21:58pm

v2

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Herman<T>.Instance 9-Apr-15 4:06am

What's the tabindexes of these controls?

oldboy24 9-Apr-15 6:33am

Hi, digimanus! What do you mean about "tabindexes"?

Herman<T>.Instance 9-Apr-15 6:50am

Hi oldboy24,
controls hav a TabIndex. It is their nr in the Tab Order. When you press TAB you go to the next control...

oldboy24 9-Apr-15 12:38pm

The TabIndex of my 3 TextBoxes in my UserControl - I have now changed to 1, 2 and 3.(They had have the Default). The behavior did not change.
If the user enter the caret (with the mouse) in one TextBox (for day, month or year) it raises the "UserControl_PreviewLostKeyboardFocus" - event first. This event should check the Inputs of the TextBoxes. All empty or a valid date - is o.k. But if one TextBox or 2 TextBoxes are empty, this is wrong. In this case I Show a MessageBox and put the Focus to one of the empty TextBoxes.

Herman<T>.Instance 9-Apr-15 13:34pm

The event is raised because you enter a TextBox object whoch is not the UserControl object. Do you really need this event?

oldboy24 9-Apr-15 14:15pm

How can I check the Input, if the user leavs the UserControl to set the Focus to the wrong TextBox?

Herman<T>.Instance 9-Apr-15 15:04pm

TextBox has OnLeave event too

oldboy24 10-Apr-15 13:55pm

Hi digimanus, do you have a link for an example?

Herman<T>.Instance 10-Apr-15 16:45pm

Just create the events....set breakpoints and learn your new world

oldboy24 13-Apr-15 6:21am

I'll try it. Thank you

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