C validating canceleventargs

In a Win Form I'm doing initial validation in the Form. To make the code short only three fields are shown in the code. Text)) Save(sender, e); } } } private bool Is Filled(string s) { if (s !

Let’s assume when we click our save button that we wish to validate the controls and display an icon if there is a problem.

First, add the following code to the Form’s constructor after the Initialize Component method: This is a handy trick to prevent implicit validation of our controls when they lose focus.

You do not have to disable the Form’s Auto Validate property.

However, I prefer to call it explicitly and handle all validation at once since you most likely will take action only if the entire control’s children pass validation. The most important thing to recognize here is how precise you can be with the validation error message in the error provider.

There are 2 code paths for validation failure, and in each case we provide the user with an appropriate error message.

The error provider simply takes a control and a message in the Set Error method and does the rest of the work for you!If the user enters invalid data they’ll see an icon shown in Figure 3.I recommend against relying on submission validation in a Windows Forms application. Set Error(text Box1, "Only numbers may be entered here"); } } namespace.Errors should be trapped sooner, as close to when they are entered as possible. The regex pattern matches any integer value, with empty strings allowed. The rest of the method sets the error provider if the match failed, or clears it if the match succeeded.Nothing is more annoying to a user than a dialog box with a laundry list of errors, and a form with as many red marks as a badly-written school paper is not far behind. Note that to clear the provider, we set it with an empty string.The rule on validation is the same as the rule on voting in my home town of Chicago: “Validate early, and validate often.”The Validating Event Windows provides a private void text Box1_Validating(object sender, Cancel Event Args e){ Regex regex = new Regex("^[0-9]*$"); if (regex.