我有以下代码将十进制输入格式化为public class WaveWriter {
private static final int OUTPUT_STREAM_BUFFER = 16384;
private File mOutFile;
private BufferedOutputStream mOutputStream;
private int mSampleRate;
private int mChannels;
private int mSampleBits;
private int mBytesWritten;
/**
* Constructor; initializes WaveWriter
*
* @param path output file path
* @param name output file name
* @param sampleRate output sample rate
* @param channels number of channels
* @param sampleBits number of bits per sample (S8LE, S16LE)
*/
public WaveWriter(String path, String name, int sampleRate, int channels,
int sampleBits) {
this.mOutFile = new File(path + File.separator + name);
this.mSampleRate = sampleRate;
this.mChannels = channels;
this.mSampleBits = sampleBits;
this.mBytesWritten = 0;
}
/**
* Constructor; Initializes WaveWriter
*
* @param file output file handle
* @param sampleRate output sample rate
* @param channels number of channels
* @param sampleBits number of bits per sample
*/
public WaveWriter(File file, int sampleRate, int channels, int sampleBits) {
this.mOutFile = file;
this.mSampleRate = sampleRate;
this.mChannels = channels;
this.mSampleBits = sampleBits;
this.mBytesWritten = 0;
}
/**
* Create output wav file
*
* @return whether file creation succeded
*
* @throws IOException if file I/O error occurs allocating header
*/
public boolean createWaveFile() throws IOException {
if (mOutFile.exists()) {
mOutFile.delete();
}
if (mOutFile.createNewFile()) {
FileOutputStream fileStream = new FileOutputStream(mOutFile);
mOutputStream = new BufferedOutputStream(fileStream, OUTPUT_STREAM_BUFFER);
//write 44 bytes of space for the header
mOutputStream.write(new byte[44]);
return true;
}
return false;
}
/**
* write audio data to ooutput file (mono). Does nothing if output
* file is not mono channel
*
* @param src audo data input buffer
* @param offset offset into src buffer
* @param length buffer size in number of samples
*
* @throws IOException if file I/O error occurs
*/
public void write(short[] src, int offset, int length) throws IOException {
if (mChannels != 1) return;
if (offset > length) throw new IndexOutOfBoundsException(
String.format("offset %d is greater than length %d", offset, length));
for (int i = offset; i<length; i++) {
writeUnsignedShortLE(mOutputStream, src[i]);
mBytesWritten += 2;
}
}
/**
* write audio data to output file (stereo). Does nothing if output file is not
* stereo channel
*
* @param left left channel audio data buffer
* @param right right channel audio data buffer
* @param offset offset into left/right buffers
* @param length buffer size in number of samples
*
* @throws IOException if file I/O error occurs
*/
public void write(short[] left, short[] right, int offset, int length) throws IOException {
if (mChannels != 2) {
return;
}
if (offset > length) {
throw new IndexOutOfBoundsException(String.format("offset %d is greater than length %d", offset, length));
}
for (int i = offset; i < length; i++) {
writeUnsignedShortLE(mOutputStream, left[i]);
writeUnsignedShortLE(mOutputStream, right[i]);
mBytesWritten += 4;
}
}
/**
* close output Wav file and write WAV header. WaveWriter cannot
* be used anymore after this method has been called
*
* @throws IOException if file I/O error occurs writing WAV header
*/
public void closeWaveFile() throws IOException {
if (mOutputStream != null) {
this.mOutputStream.flush();
this.mOutputStream.close();
}
writeWaveHeader();
}
private void writeWaveHeader() throws IOException {
// go back to the beginning of file
RandomAccessFile file = new RandomAccessFile(this.mOutFile, "rw");
file.seek(0);
int bytesPerSec = (mSampleBits + 7) / 8;
file.writeBytes("RIFF"); // WAV chunk header
file.writeInt(Integer.reverseBytes(mBytesWritten + 36)); // WAV chunk size
file.writeBytes("WAVE"); // WAV format
file.writeBytes("fmt "); // format subchunk header
file.writeInt(Integer.reverseBytes(16)); // format subchunk size
file.writeShort(Short.reverseBytes((short) 1)); // audio format
file.writeShort(Short.reverseBytes((short) mChannels)); // number of channels
file.writeInt(Integer.reverseBytes(mSampleRate)); // sample rate
file.writeInt(Integer.reverseBytes(mSampleRate * mChannels * bytesPerSec)); // byte rate
file.writeShort(Short.reverseBytes((short) (mChannels * bytesPerSec))); // block align
file.writeShort(Short.reverseBytes((short) mSampleBits)); // bits per sample
file.writeBytes("data"); // data subchunk header
file.writeInt(Integer.reverseBytes(mBytesWritten)); // data subchunk size
file.close();
file = null;
}
private static void writeUnsignedShortLE(BufferedOutputStream stream, short sample)
throws IOException {
// write() already writes the lower order byte of this short
stream.write(sample);
stream.write((sample >> 8));
}
}
。
TextBox但是，如果我在If Char.IsDigit(e.KeyChar) OrElse e.KeyChar = "."c Then
If e.KeyChar = "."c Then
If txtPrice.Text.Contains("."c) Then
e.Handled = True
End If
ElseIf Char.IsDigit(e.KeyChar) Then
If txtPrice.Text.Contains("."c) Then
Dim value As String = txtPrice.Text
Dim units As String = value.Substring(value.IndexOf("."c) + 1)
If units.Length >= 2 Then
e.Handled = True
End If
End If
End If
ElseIf e.KeyChar <> Chr(8) Then
e.Handled = True
End If
中输入一个值，那么一切正常。 10.50，当我然后尝试删除第一个0并将值更改为11.50时，它将不允许我，因为小数点后面有2个数字取消所有其他用户输入，以确保只有2个小数位可以输入。
有没有办法可以对此进行验证，以检查是否在小数点之前或之后添加了数字？或者它是否可以根据插入符位置进行检查？
可能有一种更简单的方法来验证TextBox中的小数，但是此代码也用于验证网格和其他控件，因此需要使用此格式的内容。
答案 0 :(得分：0)
检查SelectionStart属性。
If units.Length >= 2 AndAlso txtPrice.SelectionStart > txtPrice.Text.IndexOf(".") Then
e.Handled = True
End If
以上代码解释：
如果.您尝试添加另一个文字之后的文字已有2个字符，请禁止按键。如果在.之前添加，则允许。