- #VB NET TEXTBOX VALIDATING EVENT ERRORPROVIDER CODE#
- #VB NET TEXTBOX VALIDATING EVENT ERRORPROVIDER WINDOWS#
I've also tried to bubble the validating event up to the main form through a custom event, so that the validating logic handled from the highest level in the solution, and the message box is displayed from the main form. This leads me to believe that it may be some bug in the way that VB.net handles lost focus/validating events of controls instantiated in user controls. I've also noticed that if I don't display a messagebox in the validating event, the program works just fine, even when focus is lost to outside the user control. I've noticed that if switch to a different tab, then return to this tab, the user control gains functionality again and events trigger as expected. The program doesn't completely break, but none of the other buttons or check boxes in the user control trigger their corresponding events. clicking on another tab or clicking on the menu strip) the user control loses functionality. However, when focus is lost outside this user control (ie.
This validating event works perfectly when focus is lost to another control inside the user control on this tab. If the email address is not in the standard format (containing '' and '.'), the validation fails, an ErrorProvider icon is displayed, and the event is canceled.
#VB NET TEXTBOX VALIDATING EVENT ERRORPROVIDER CODE#
The following code example uses the derived class TextBox and validates an email address that the user enters.
If it is outside this range, the method cancels the event (using canceleventargs) and displays a MessageBox to the user instructing them to input a value in the specified range. Public Custom Event Validating As CancelEventHandler Event Type CancelEventHandler Examples. Validation that is performed using Validating event, the Causes Validation property and ErrorProvider component. essentially the method checks if the entry is within the range of 0 to 100 when the user tries leaving the text box control. I've written the event handler sub for this validating event. Correct me if I'm wrong here, but it appears that I could do the following: Private Sub textBox1Validating(ByVal sender As Object, ByVal e As ) Handles textBox1.Validating 'check to see if the textbox has is correct or not If > 0 Then If IsNumeric. In one of my user controls I want to validate numeric entries upon leaving a TextBox (ie. Take a look at this MSDN article for specifics of using the ErrorProvider class. ErrorProvider component in VB.NET Visual Studio 2010 ErrorProvider control in VB.NET Read user input using While loop in Vb.Net User Define Exception in VB.NET WPF Grid Using VB. Under each of the three tabs there is a custom user control that I've defined for encapsulating the functionality of each tab.
#VB NET TEXTBOX VALIDATING EVENT ERRORPROVIDER WINDOWS#
I really don't see this as an ideal approach.I'm making a windows form application that has a primary form (MainForm) holding a tab control. I default everything to not CauseValidation, enables them all before I use the event for validating the whole form, and disables them all after again. So basic question is, what is the best approach to validate a specific set of controls only when I want to and not when focus is lost from the control?ĮDIT: presently as a work around, I have a method that toggles the "CausesValidation" property on and off. I have been using the ErrorProvider class to support this visually. They use "e.Cancel = true " to cancel the validation. However, I don't want to have the validation run when the textboxes lose focus, only when the whole form is being validated.Įach control that I want to be validated, I have registered with the "validating" event. I only want to close the form if the validation is successful. MessageBox.Show("Validation passed with flying colours. So I have an event that fires for that like so: if (!this.ValidateChildren())
Maybe defer to a private method per control if the validation is complex. 2) Write a validation routine, maybe directly under the button click, that loops through the control collection, checking the value/validity of the control's content. However, I only want this validation to occur when I click a button. 1) Define the controls you want validated in a collection of some sort. I have a C# winform project that I want to validate a form before closing.
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