C#

Thanks for your reply but I did the same before, but did not receive any response

Thanks for your cooperation friends. But I find myself sharing the reason that other friends, if they can find this problem, can use grammar code in this way (or in your program). Saman from Iran

D:\Fd\DevExpressUniversal2019.exe /Q /EULA:accept /DEBUG

[DllImport("user32.dll")]
public static extern int SendMessage(IntPtr hWnd, int wMsg, IntPtr wParam, IntPtr lParam);

    IntPtr windowHandle = IntPtr.Zero;
    if (this.InvokeRequired)
    {
        this.Invoke((MethodInvoker)delegate
        {
            windowHandle = this.Handle;
        });
     }
     else
     {
         windowHandle = this.Handle;
     }
     SendMessage(windowHandle, DBT_DEVNODES_CHANGED, IntPtr.Zero, IntPtr.Zero);  

{
    int devType;
    char c;

    if (m.Msg == WM_DEVICECHANGE)
    {
        // WM_DEVICECHANGE can have several meanings depending on the WParam value...
        switch (m.WParam.ToInt32())
        {

public static bool HandleDeviceChange = true;


public void WndProc(ref Message m)
{
    int devType;
    char c;

    if (HandleDeviceChange && m.Msg == WM_DEVICECHANGE)
    {
        // WM_DEVICECHANGE can have several meanings depending on the WParam value...
        switch (m.WParam.ToInt32())
        {

Brian_TheLion wrote:

A lot of books deal with the console side of c# more than the form side.

MessageBox.Show("The Yes button was clicked", "My form event handler", MessageBoxButtons.OK, MessageBoxIcon.Information);

private void YesButton_Click(object sender, EventArgs e)
    {
    MessageBox.Show("The Yes button was clicked", "My form event handler", MessageBoxButtons.OK, MessageBoxIcon.Information);
    }

private           So that it is only usable inside the form.
void              Because it doesn't return a value
YesButton_Click   Name of the handler method: YesButton Click event
object sender     "sender" is object that raised the event (useful if several buttons share the same handler)
EventArgs e       Provides extra information on the event if you need it.

a TextBox 'tbxQuizQuestion

two RadioButtons 'rbtnYes 'rbtnNo : the 'CheckChanged for both these RadioButtons is set to 'rbtn_CheckedChanged

a Button 'btnNextQuestion

// used to reset RadioButton state
private bool ignoreRBCheckEvent = true;

private List<string> questions = new List<string>
{
    "who", "when", "where", "how"
};

// holds results
private Dictionary<int, bool> QA = new Dictionary<int, bool>();

// question counter
private int qcnt = 0;

// show the quiz
private void btnShowQuiz_Click(object sender, EventArgs e)
{
    QA.Clear();
    qcnt = 0;

    tbxQuizQuestion.Text = questions[0];

    btnNextQuestion.Enabled = false;

    rbtnYes.Enabled = true;
    rbtnYes.CheckedChanged += rbtn_CheckedChanged;

    rbtnNo.Enabled = true;
    rbtnNo.CheckedChanged += rbtn_CheckedChanged;

    ignoreRBCheckEvent = false;

    grpbxQuiz.Visible = true;

    // set the clip
    Cursor.Clip = grpbxQuiz.RectangleToScreen(grpbxQuiz.ClientRectangle);
}

private void BtnNextQuestion_Click(object sender, EventArgs e)
{
    ignoreRBCheckEvent = true;

    rbtnYes.Checked = false;
    rbtnNo.Checked = false;

    btnNextQuestion.Enabled = false;

    tbxQuizQuestion.Text = questions[qcnt];

    ignoreRBCheckEvent = false;
}

private void rbtn_CheckedChanged(object sender, EventArgs e)
{
    if (ignoreRBCheckEvent) return;

    QA.Add(qcnt++, rbtnYes.Checked);

    if (qcnt < questions.Count)
    {
        btnNextQuestion.Enabled = true;
    }
    else
    {
        // release the clip
        Cursor.Clip = Rectangle.Empty;
        grpbxQuiz.Visible = false;
        OnQuizFinished();

    }
}

// inspect the results
public void OnQuizFinished()
{
    foreach (var kvp in QA)
    {
        Console.WriteLine($"({kvp.Key}) \"{questions[kvp.Key]}\" | {kvp.Value}");
    }
}