I would like to clarify that I already know how to check if a form is loaded by setting a boolean variable flag (Ex: dim FormIsLoaded as boolean
) and setting it to True
after the Load
event of the form, to restrict the usage of the [Enum].Parse
method that is causing the exceptio in my coden.
But that is not what I'm asking for, this is not a typicall question, please continue reading...
I have an eventhandler like this:
''' <summary>
''' Indicates the resulting Batch command redirection.
''' </summary>
Private CommandRedirection As Reg2Bat.CommandRedirection =
Reg2Bat.CommandRedirection.Standard
Private Sub KryptonRadioButton_CommandRedirections_CheckedChanged(sender As Object, e As EventArgs) Handles _
KryptonRadioButton_CommandRedirection_Standard.CheckedChanged,
KryptonRadioButton_CommandRedirection_Error.CheckedChanged,
KryptonRadioButton_CommandRedirection_All.CheckedChanged,
KryptonRadioButton_CommandRedirection_None.CheckedChanged
If CBool(sender.checked) Then
CommandRedirection = [Enum].Parse(GetType(CMD.CommandRedirection),
CStr(sender.tag), True)
End If
End Sub
But the If
is giving me an error of type An unhandled exception of type 'System.InvalidOperationException' occurred in Program.exe
and I'm sure that the error occurs because the form is not totally loaded before the eventhandler tries to access the value of the control.
StackTrace:
en System.Enum.TryParseEnum(Type enumType, String value, Boolean ignoreCase, EnumResult& parseResult)
en System.Enum.Parse(Type enumType, String value, Boolean ignoreCase)
en Reg2Bat.GUI.KryptonRadioButton_CommandRedirection_Standard_CheckedChanged(Object sender, EventArgs e)
en C:\Users\Administrador\Desktop\Reg2Bat\Reg2Bat\UserInterfaces\GUI\GUI.vb:línea 271
en ComponentFactory.Krypton.Toolkit.KryptonRadioButton.set_Checked(Booleanvalue)
en Reg2Bat.GUI.InitializeComponent()
en C:\Users\Administrador\Desktop\Reg2Bat\Reg2Bat\UserInterfaces\GUI\GUI.Designer.vb:línea 104
en Reg2Bat.GUI..ctor()
en C:\Users\Administrador\Desktop\Reg2Bat\Reg2Bat\User Interfaces\GUI\GUI.vb:línea 49
I would like to improve a 'FormIsLoaded?' checking without writting unnecessary variables (boolean flags) to keep my code more pretty and simplified, so, as the title of my question says, what I'm asking for is that if exist a property, or just, an In-One-Line solution to check whether a form is fully loaded in any moment.
I'm also asking this to know more improved alternatives than setting a boolean to check that a form is loaded.
By the moment I'm trying the property (Me.IsAccessible
), and seems that is working correctlly because now the [Enum].Parse
method does not throws any exception, but I'm not sure of what the property is really checking (I've read the IntelliSense help of the prop but nothing).
Private Sub KryptonRadioButton_CommandRedirections_CheckedChanged(sender As Object, e As EventArgs) Handles _
KryptonRadioButton_CommandRedirection_Standard.CheckedChanged,
KryptonRadioButton_CommandRedirection_Error.CheckedChanged,
KryptonRadioButton_CommandRedirection_All.CheckedChanged,
KryptonRadioButton_CommandRedirection_None.CheckedChanged
If Me.IsAccessible Then
If CBool(sender.checked) Then
CommandRedirection = [Enum].Parse(GetType(Reg2Bat.CommandRedirection),
CStr(sender.tag), True)
End If
End If
MsgBox(CommandRedirection.ToString)
End Sub
So, using the Me.IsAccessible
property it's the properlly solution to check if a form/controls are loaded? If not, there is a property that could check this?.
It is like a container for holding different control that allows the user to interact with an application. The controls are an object in a form such as buttons, Textboxes, Textarea, labels, etc. to perform some action. However, we can add any control to the runtime by creating an instance of it. A Form uses a System.
You can manually place controls on a form in two ways: by using the Toolbox and by using the field list.
Control.Name Property (System.
I believe what you're looking for is Form.IsHandleCreated
to confirm is is built (and has gone through InitialiseComponent()
routine in the .Designer file.)
After that it is worth checking Form.IsDisposed
to make sure it has not since been destroyed.
This is more difficult in multiple threaded applications because unless you can execute the check on the form's owning thread, its state change can happen after doing the test.
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