Vb net using errorprovider on multiple controls

#VB NET USING ERRORPROVIDER ON MULTIPLE CONTROLS CODE#

The idea behind Enumerations (or Enums as they are often called) is that they let you provide meaningful names that are indexed by their integer value. An Enumeration is really nothing more than a list of numeric values, each value equating to some kind of textual description. This DialogResult is what is known as an Enumeration. In line 5, I have created a variable named вЂresultвЂ™ that will hold a DialogResult. If result = Then Me.(F2.InputTextBox.Text)

#VB NET USING ERRORPROVIDER ON MULTIPLE CONTROLS CODE#

If youвЂ™d like to test this, try changing the code so that the Show method is used in place of ShowDialog. And thatвЂ™s why the value from the text box is still visible to Form1 even though Form2 appears to be closed. This applies even if you explicitly call the Close method as I have in the code snippet above. It turns out that when you run the Close method on a modal form that the form doesnвЂ™t get closed it is only hidden. But if youвЂ™re wondering how line 6 in the Click event handler of the Button on Form1 can possibly know what the value is in a control on a Form вЂ“ Form2 вЂ“ that has now been closed, then (1) Well done for thinking it through and (2) HereвЂ™s the answer. If youвЂ™re happy to have a cheap and cheerful, reasonably safe way of passing the data back like this, without wondering how it works, then go ahead thatвЂ™s all you need to know. So, clicking on the button (or using the built-in one at the top right of the Form) will remove the modal form from view. In the Form2 instance, IвЂ™ve used the Close method of the Form class to close that modal form when the button is clicked: When it is run, the value from the text box is added to the list box on Form1. Recall from the earlier post that nothing happens on or to Form1 until the modal Form2 is closed, youвЂ™ll understand that the code in line 6 doesnвЂ™t run until Form2 is closed. Line 6 takes the Text content of the Form2 TextBox named InputTextBox and displays it in the ListBox on Form1. Anyhow, whether you set it explicitly or not, once ShowDialog runs, Form1 will be the owning form of Form2 and so Form2 will be owned by Form1.

However, if thereвЂ™s a built-in feature that will make your project less likely to fail, itвЂ™s always a good policy to use it. ThatвЂ™s because by default the owner of the modal form will be the currently active window вЂ“ which in this limited scenario will always be Form1. In the examples in the earlier posts I didnвЂ™t assign a value (an argument) to this parameter and in fact itвЂ™s not strictly necessary here either. Notice that the ShowDialog method will take a parameter that sets Form1 as the owner of Form2. Line 3 uses the ShowDialog method to display the newly created form instance.

Line 2 creates a new instance of the Form2 class. Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click The code in the Click event of the Button on Form1 (the Main Form) looks like this: Form1 contains the controls shown in the screenshot below: To demonstrate this, IвЂ™ve created two forms, Form1 and Form2. You saw ShowDialog in action in this earlier post. That is, where the ShowDialog method is used to show the second form. I do think that there is one acceptable exception to this rule and that is where you directly access data held on a form that is shown modally. In these examples, the instance of the Form2 class is represented by a variable named F2.ДЄs IвЂ™ll explain later, the principles of Object Oriented Programming mean itвЂ™s generally not thought to be a good idea to let one form directly access a control on another, even when itвЂ™s possible to do so. Just for clarification, whenever I talk about вЂthe user sees Form2вЂ™ or вЂcontrol returns to Form1вЂ™, in all those kind of cases IвЂ™m talking about a single instance of the Form1 class or the Form2 class. In this post IвЂ™m going to take another look at modal forms. There are several ways of doing this and which you use is often just a matter of personal preference. Very often though, if you have multiple forms in use then youвЂ™ll want one or more forms to be able to read the data on another form or forms.

In the previous posts, I talked about ways of showing, hiding and switching between forms in VB.NET.

Vb net using errorprovider on multiple controls