/// <summary>
/// 打开shp、shx文件流
/// 读取shp、shx信息时需要首先执行此操作
/// 同时操作头文件读取和ShxRecord、ShpRecord示例化
/// </summary>
/// <param name="ofs"></param>
public void Open(Stream shpStream, Stream shxStream)
{
if (mShpFile != null)
{
Close();
}
mShpFile = shpStream;
mShxFile = shxStream;
mShpFileReader = null;
mShpFileWriter = null;
mShxFileReader = null;
mShxFileWriter = null;
if (mShpFile.CanRead)
{
mShpFileReader = new BinaryReader(mShpFile);
}
if (mShpFile.CanWrite)
{
mShpFileWriter = new BinaryWriter(mShpFile);
}
if (mShxFile.CanRead)
{
mShxFileReader = new BinaryReader(mShxFile);
}
if (mShxFile.CanWrite)
{
mShxFileWriter = new BinaryWriter(mShxFile);
}
//reset position
mRecordsReadCount = 0;
//assume header is not written
mHeaderWritten = false;
//read the header
if (shpStream.CanRead)
{
//try to read the header...
try
{
mHeader.Read(mShpFileReader);
mHeaderWritten = true;
}
catch (EndOfStreamException)
{
//could not read header, file is empty
mHeader = new ShpHeader();
mHeaderWritten = false;
}
}
if (mShpFile != null)
{
mIsReadOnly = !mShpFile.CanWrite;
mIsForwardOnly = !mShpFile.CanSeek;
}
mShxRecord = new ShxRecord(mHeader);
mShpRecord = new ShpRecord(mHeader);
}
/// <summary>
/// 更新header信息 清除(flush)buffers 关闭streams
/// 在操作完shp文件后必须调用此方法
/// </summary>
public void Close()
{
//Empty header...
//--------------------------------
mHeader = new ShpHeader();
mHeaderWritten = false;
//reset current record index
//--------------------------------
mRecordsReadCount = 0;
//Close streams...
//--------------------------------
if (mShpFileWriter != null)
{
mShpFileWriter.Flush();
mShpFileWriter.Close();
}
if (mShpFileReader != null)
{
mShpFileReader.Close();
}
if (mShpFile != null)
{
mShpFile.Close();
}
if (mShxFileWriter != null)
{
mShxFileWriter.Flush();
mShxFileWriter.Close();
}
if (mShxFileReader != null)
{
mShxFileReader.Close();
}
if (mShxFile != null)
{
mShxFile.Close();
}
//set streams to null
//--------------------------------
mShpFileReader = null;
mShpFileWriter = null;
mShpFile = null;
mShxFileReader = null;
mShxFileWriter = null;
mShxFile = null;
mFileName = "";
}
/// <summary>
/// 根据RecordDic求header
/// </summary>
private void TransHeader()
{
if (mHeader == null)
{
mHeader = new ShpHeader();
}
mHeader.FileCode = 9994; //固定
mHeader.FileLength = 50; //文件头
foreach (var item in mRecordDic)
{
mHeader.FileLength += item.Value.GeoShape.DataLength + 4; //每条记录多出4字
}
mHeader.Version = 1000; //固定
mHeader.GeoType = mRecordDic[1].GeoShape.GeoType;
GetBorder(); //求包围盒
}
/// <summary>
///
/// </summary>
public ShpFile()
{
mHeader = new ShpHeader();
}
/// <summary>
/// 构造时传入已经实例化的ShpHeader对象
/// </summary>
/// <param name="oHeader"></param>
public ShpRecord(ShpHeader oHeader)
{
mHeader = oHeader;
}