WinForm C＃：检查首次运行并显示消息

Question

I am creating a winform application containing first run check. I've been following these 2 articles:

• How can I check if a program is running for the first time?
• Windows Forms User Settings in C#

First run check is supposed to check if application has ever been run and if not, it should show some message to the user. Problem i am having is, that this message is displayed before winform application is initialized/displayed and I am not able to find out why. Here is my code:

Program.cs

public static void Main()
{
    Application.EnableVisualStyles();
    Application.SetCompatibleTextRenderingDefault(false);
    Application.Run(new Form1());
}

Form1.cs

public Form1()
{
    this.InitializeComponent();
    CheckFirstRun();
}

private static void CheckFirstRun()
{
    if(Settings.Default.FirstRun)
    {
        MessageBox.Show(
            "First run");
        Settings.Default.FirstRun = false;
        Settings.Default.Save();
}

It shows Message box with msg: "First run" and after clicking OK button it shows WinForm. What I am trying to achieve is to Display WinForm first and if it is first run then show this msgBox.

Any ideas?

Answer 1

Instead of calling CheckFirstRun() from constructor you can call it Form.Shown

Form.Shown Event

The Shown event is only raised the first time a form is displayed; subsequently minimizing, maximizing, restoring, hiding, showing, or invalidating and repainting will not raise this event

private void Form1_Shown(Object sender, EventArgs e) 
{
    CheckFirstRun();
}

Overriding OnShown

The OnShown method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class, MSDN

Notes to Inheritors When overriding OnShown in a derived class, be sure to call the base class's OnShown method so that registered delegates receive the event, MSDN .

protected override void OnShown(EventArgs e)
{
    base.OnShown(e);
    CheckFirstRun();
}

Answer 2

Call CheckFirstRun from OnShown method.

The Shown event occurs whenever the form is first shown.

[...]

The OnShown method also allows derived classes to handle the event without attaching a delegate. This is the preferred technique for handling the event in a derived class.

public Form1()
{
    this.InitializeComponent();
}

protected override void OnShown(EventArgs e)
{
    base.OnShown(e);
    CheckFirstRun();
}

private static void CheckFirstRun()
{
    if(Settings.Default.FirstRun)
    {
        MessageBox.Show(
            "First run");
        Settings.Default.FirstRun = false;
        Settings.Default.Save();
    }
}

Answer 3

Use this event to fire the event after form has load.

private void Form1_Shown(Object sender, EventArgs e) {

MessageBox.Show("First run.");

}