Problem with c# events

Question

I need to implement Pause and Resume events of a MP3 player inside the same button click event. following is the code i have tried and its not working,Can any one give me the solution

private void button3_Click(object sender, EventArgs e)
{
    if (button3.Text == "Pause")
    {
        CommandString = "pause mp3file";
        mciSendString(CommandString, null, 0, 0);
        Status = true;
        button3.Text = "Resume";           
    }
    if (button3.Text == "Resume")
    {   
        CommandString = "resume mp3file";
        mciSendString(CommandString, null, 0, 0);
    }
}

What is not working? The if condition is not verified or the mciSendString function? If it's the mciSendString function you will have to describe what this function is, where it comes from, what it is supposed to do, etc... — Darin Dimitrov
– Darin Dimitrov, Commented Aug 23, 2010 at 8:04
"it's not working" is unfortunately not very helpful for us. Can you be more specific? Do you get errors? Does the pause work, but not the resume, or the other way around? Do the buttons fail, or the MP3? Exceptions, crashes? What happens when you place a breakpoint in the event handler, is it hit and does the execution follow the path you expect? — Abel
– Abel, Commented Aug 23, 2010 at 8:06
It appears that depending on the text on the button you decide which state your MP3 player is in. Whether or not this is a wise choice is a different question but it would be helpful to understand what mciSendString() does. I also agree with previous comments: "It's not working." isn't specific enough to provide good answers. — Manfred
– Manfred, Commented Aug 23, 2010 at 8:09

Lewray · Accepted Answer · 2010-08-23 08:07:10Z

5

You are changing the button3.Text property within the first if statement. When the second if statement is tested it is true (both if statements are running with each button click when the Text property is "Pause")

Use if, else to run one code block or another.

Use if, else if statements if you want a test to be run on the second code block also.

You should also take account of the possibility that neither of these cases is true.

if (button3.Text == "Pause")
{
    CommandString = "pause mp3file";
    mciSendString(CommandString, null, 0, 0);
    Status = true;
    button3.Text = "Resume";
}
else if(button3.Text == "Resume")
{   
    CommandString = "resume mp3file";
    mciSendString(CommandString, null, 0, 0);
    button3.Text = "Pause";
}

answered Aug 23, 2010 at 8:07

Lewray

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1 Comment

Abel Over a year ago

+1 for good advice (but missed the change back to "Pause" though)

Arseny · Accepted Answer · 2010-08-23 08:21:35Z

4

at first glance it won't work properly 'cause in 2 case

if (button3.Text == "Resume")
{   
    CommandString = "resume mp3file";
    mciSendString(CommandString, null, 0, 0);
}

you missed the line:

button3.Text = "Pause";

Actually it's not a good idea to check the button state by its text property. As a simple solution you need to have a boolean flag to check against it.

edited Aug 23, 2010 at 8:21

answered Aug 23, 2010 at 8:07

Arseny

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2 Comments

Lewray Over a year ago

Ah... I missed that, but noticed the two if statements

Arseny Over a year ago

@Lewray it's not you but the author :)

Matt Jacobsen · Accepted Answer · 2010-08-23 08:21:32Z

1

you have two if consecutive if statements. You need just one if/else statement.

change your code to:

    if (button3.Text == "Pause")
    {
        CommandString = "pause mp3file";
        mciSendString(CommandString, null, 0, 0);
        Status = true;
        button3.Text = "Resume";           
    }
    else if (button3.Text == "Resume")
    {   
        CommandString = "resume mp3file";
        mciSendString(CommandString, null, 0, 0);
    }

answered Aug 23, 2010 at 8:21

Matt Jacobsen

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Comments

user406632 · Accepted Answer · 2010-08-23 08:25:16Z

The problem is:

By the time you get to the second if statement, you have changed the Text of the button, hence both statements are being run...

Here is a quick test:

        if (button1.Text == "Pause")
        {
            label1.Text = label1.Text + " saw pause ";
            button1.Text = "Resume";


        }
        if (button1.Text == "Resume")
        {
            label1.Text = label1.Text + " saw resume ";
            button1.Text = "Pause";
        }

returns: label1 saw pause saw resume.

There are two ways to fix this:

You could insert a 'return;' statement within each if statement:

private void button3_Click(object sender, EventArgs e)
{

    if (button3.Text == "Pause")
    {
        CommandString = "pause mp3file";
        mciSendString(CommandString, null, 0, 0);
        Status = true;
        button3.Text = "Resume";
        return;
    }
    if (button3.Text == "Resume")
    {   
        CommandString = "resume mp3file";
        mciSendString(CommandString, null, 0, 0);
        button3.Text = "Pause";
        return;
    }
}

Or secondly, you could capture the value of the button text once:

private void button3_Click(object sender, EventArgs e)
{
    String value = button3.Text;
    if (value == "Pause")
    {
        CommandString = "pause mp3file";
        mciSendString(CommandString, null, 0, 0);
        Status = true;
        button3.Text = "Resume";

    }
    if (value == "Resume")
    {   
        CommandString = "resume mp3file";
        mciSendString(CommandString, null, 0, 0);
        buton3.Text = "Pause"; // As mentioned before, this is required too.
    }
}

Hope that helps.

Steve

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