如何在 c# WPF 中录制 WAV？

Question

I can get this code to work in a console application. But I want this to work on a Windows Forms application in c# visual studio 2010. Here is my code:

public partial class MainWindow : Window
{
[DllImport("winmm.dll", EntryPoint = "mciSendStringA", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
private static extern int mciSendString(string lpstrCommand, string lpstrReturnString, int uReturnLength, int hwndCallback);

...

private void buttonRecordWAV_click(object sender, RoutedEventArgs e)
    {
        mciSendString("open new Type waveaudio Alias recsound", "", 0, 0);
        mciSendString("record recsound", "", 0, 0);
        Console.WriteLine("recording, press Enter to stop and save ...");
        Console.ReadLine();
        if (System.Windows.Forms.MessageBox.Show("recording, press OK to stop recording and save", "Recording...", MessageBoxButtons.OK) == System.Windows.Forms.DialogResult.OK)
            {
                System.Windows.Forms.MessageBox.Show("you entered the if statement");
                mciSendString("save recsound result.wav", "", 0, 0);
                mciSendString("close recsound ", "", 0, 0);
            }

    }

However, when I execute this, I don't see any 'result.wav' file in the bin/Debug folder. When I run this code on a console application, it works, and I can see a 'result.wav' in the bin/Debug folder and when I play that file, I hear what ever I recorded. Anybody know how to make this work in the C# Forms Application? Thanks.

Answer 1

You have a strange mixture of technologies going on in your sample code. As you are using Console.ReadLine in an application that has a form as a front end. You are also using System.Windows.Forms.MessageBox which is a winforms class, not a WPF class, here you should be using System.Windows.MessageBox .

I just put a quick same together however using snippets from your example and it works for me. Sample as follows; markup:

<Grid>
    <Button x:Name="buttonRecordWav" Click="buttonRecordWav_Click">Start Recording</Button>
</Grid>

And in the code behind:

public enum MCIErrors
{
    NO_ERROR = 0,
    MCIERR_BASE = 256,
    MCIERR_INVALID_DEVICE_ID = 257,
    MCIERR_UNRECOGNIZED_KEYWORD = 259,
    MCIERR_UNRECOGNIZED_COMMAND = 261,
    MCIERR_HARDWARE = 262,
    MCIERR_INVALID_DEVICE_NAME = 263,
    MCIERR_OUT_OF_MEMORY = 264,
    MCIERR_DEVICE_OPEN = 265,
    MCIERR_CANNOT_LOAD_DRIVER = 266,
    MCIERR_MISSING_COMMAND_STRING = 267,
    MCIERR_PARAM_OVERFLOW = 268,
    MCIERR_MISSING_STRING_ARGUMENT = 269,
    MCIERR_BAD_INTEGER = 270,
    MCIERR_PARSER_INTERNAL = 271,
    MCIERR_DRIVER_INTERNAL = 272,
    MCIERR_MISSING_PARAMETER = 273,
    MCIERR_UNSUPPORTED_FUNCTION = 274,
    MCIERR_FILE_NOT_FOUND = 275,
    MCIERR_DEVICE_NOT_READY = 276,
    MCIERR_INTERNAL = 277,
    MCIERR_DRIVER = 278,
    MCIERR_CANNOT_USE_ALL = 279,
    MCIERR_MULTIPLE = 280,
    MCIERR_EXTENSION_NOT_FOUND = 281,
    MCIERR_OUTOFRANGE = 282,
    MCIERR_FLAGS_NOT_COMPATIBLE = 283,
    MCIERR_FILE_NOT_SAVED = 286,
    MCIERR_DEVICE_TYPE_REQUIRED = 287,
    MCIERR_DEVICE_LOCKED = 288,
    MCIERR_DUPLICATE_ALIAS = 289,
    MCIERR_BAD_CONSTANT = 290,
    MCIERR_MUST_USE_SHAREABLE = 291,
    MCIERR_MISSING_DEVICE_NAME = 292,
    MCIERR_BAD_TIME_FORMAT = 293,
    MCIERR_NO_CLOSING_QUOTE = 294,
    MCIERR_DUPLICATE_FLAGS = 295,
    MCIERR_INVALID_FILE = 296,
    MCIERR_NULL_PARAMETER_BLOCK = 297,
    MCIERR_UNNAMED_RESOURCE = 298,
    MCIERR_NEW_REQUIRES_ALIAS = 299,
    MCIERR_NOTIFY_ON_AUTO_OPEN = 300,
    MCIERR_NO_ELEMENT_ALLOWED = 301,
    MCIERR_NONAPPLICABLE_FUNCTION = 302,
    MCIERR_ILLEGAL_FOR_AUTO_OPEN = 303,
    MCIERR_FILENAME_REQUIRED = 304,
    MCIERR_EXTRA_CHARACTERS = 305,
    MCIERR_DEVICE_NOT_INSTALLED = 306,
    MCIERR_GET_CD = 307,
    MCIERR_SET_CD = 308,
    MCIERR_SET_DRIVE = 309,
    MCIERR_DEVICE_LENGTH = 310,
    MCIERR_DEVICE_ORD_LENGTH = 311,
    MCIERR_NO_INTEGER = 312,
    MCIERR_WAVE_OUTPUTSINUSE = 320,
    MCIERR_WAVE_SETOUTPUTINUSE = 321,
    MCIERR_WAVE_INPUTSINUSE = 322,
    MCIERR_WAVE_SETINPUTINUSE = 323,
    MCIERR_WAVE_OUTPUTUNSPECIFIED = 324,
    MCIERR_WAVE_INPUTUNSPECIFIED = 325,
    MCIERR_WAVE_OUTPUTSUNSUITABLE = 326,
    MCIERR_WAVE_SETOUTPUTUNSUITABLE = 327,
    MCIERR_WAVE_INPUTSUNSUITABLE = 328,
    MCIERR_WAVE_SETINPUTUNSUITABLE = 329,
    MCIERR_SEQ_DIV_INCOMPATIBLE = 336,
    MCIERR_SEQ_PORT_INUSE = 337,
    MCIERR_SEQ_PORT_NONEXISTENT = 338,
    MCIERR_SEQ_PORT_MAPNODEVICE = 339,
    MCIERR_SEQ_PORT_MISCERROR = 340,
    MCIERR_SEQ_TIMER = 341,
    MCIERR_SEQ_PORTUNSPECIFIED = 342,
    MCIERR_SEQ_NOMIDIPRESENT = 343,
    MCIERR_NO_WINDOW = 346,
    MCIERR_CREATEWINDOW = 347,
    MCIERR_FILE_READ = 348,
    MCIERR_FILE_WRITE = 349,
    MCIERR_CUSTOM_DRIVER_BASE = 512
};

[DllImport("winmm.dll", EntryPoint = "mciSendStringA", CharSet = CharSet.Ansi, SetLastError = true, ExactSpelling = true)]
private static extern int mciSendString(string lpstrCommand, string lpstrReturnString, int uReturnLength, int hwndCallback);

private bool _recording = false;

private void buttonRecordWav_Click(object sender, RoutedEventArgs e)
{            
    MCIErrors result;
    if (!_recording)
    {
        result = (MCIErrors)mciSendString("open new Type waveaudio Alias recsound", "", 0, 0);
        if (result != MCIErrors.NO_ERROR)
        {
            MessageBox.Show("Error code: " + result.ToString());
            return;
        }
        result = (MCIErrors)mciSendString("record recsound", "", 0, 0);
        if (result != MCIErrors.NO_ERROR)
        {
            MessageBox.Show("Error code: " + result.ToString());
            return;
        }
        buttonRecordWav.Content = "Stop Recording";
        _recording = true;
    }
    else
    {
        result = (MCIErrors)mciSendString("save recsound result.wav", "", 0, 0);
        if (result != MCIErrors.NO_ERROR)
        {
             MessageBox.Show("Error code: " + result.ToString());
             return;
        }
        result = (MCIErrors)mciSendString("close recsound ", "", 0, 0);
        if (result != MCIErrors.NO_ERROR)
        {
            MessageBox.Show("Error code: " + result.ToString());
            return;
        }
        buttonRecordWav.Content = "Start Recording";
        _recording = false;
    }                            
}

If I run that, I get the wav file created as expected. Documentation on the mciSendString method here:

mciSendString function

Answer 2

couldn't comment on the accepted solution (no rep) but ppl's problem with the accepted solution is due to spaces in the file path. to resolve, just pass the full path to mciSendString and wrap it in quotes , like:

string fullPath = @"c:\path with spaces\result.wav";
result = (MCIErrors)mciSendString("save recsound \"" + fullPath + "\"", "", 0, 0);