Textbox onvalidating

As for validating the text, it can range from simply ensuring there is value (i.e., not an empty string) or more complex task such as validating the format of an email address. Once you have written a validation function for a specific format, convert it into a snippet, so the next time you need to validate similar data, you will save time by simply inserting your snippet.

The bad news is that you have to script your validation and it can change depending on the data type and format. Validation Example 1: Checking if a Text Box Field is Empty For the first example, we will create a simple function that will ensure the field is empty as well as making sure it doesn’t only contain blank spaces.

Note: If the Validation was canceled in the Validating Event, then this event will not be called.

This property indicates whether the control causes validation to be performed on any controls that require validation when it receives focus.

Let us assume that we have two standard textboxes on the form, and we wanted one of them to exhibit behavior similar to a Rad Text Box, and the other one as a Rad Numeric Text Box.

In this case, the declaration of the two textboxes, along with the Rad Input Manager, would look like this: Each of the Setting tags contains a Behavior ID, which is used to identity settings pertaining to a given text box.

Since we are canceling, the focus will remain on the Text Box until the user enters the correct format. You can have a label to display the error message or change the foreground color of the Text Box or use a Tool Tip control to display a popup message.

For example, let us assume that we have a repeater hosting a text box.

Further, if we want the text box(es) nested in the repeater to accept only e-mail addresses (a regular expression is used to determine this behavior), the setup would look something like: An enumeration which is used to determine how the input control behaves when it first gets input focus.

Example use of a regular expression in Power Shell: In this example we are matching any string that contains the word “shell”.

We will not go into details on how to use Regular Expressions, since it’s an extensive subject unto itself.

The possible values are Caret To Beginning, Caret To End, None and Select All.

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Hab eine klasse von textBox abgeleitet, und will ein rotes dreieck raufmalen. Die methhode onValidating funktioniert wenn es ein pflichfeld ist wird das. 
09-Nov-2018 22:04
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Die Veränderung einer TextBox im KeyDown-Event verhindern zu wollen. findet man in OnValidating durchaus eine elegante Lösung. 
09-Nov-2018 22:08
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Textbox onvalidating introduction

Textbox onvalidating

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