static ShapefileHeader ReadFileHeader(BinaryReader br) //用于读取文件头的函数
{ //*************************************
/*
* byte[] buff = br.ReadBytes(Marshal.SizeOf(typeof(ShapefileHeader)));
* GCHandle handle = GCHandle.Alloc(buff, GCHandleType.Pinned);//handle读取buff数组在内存中的指针
* //指针指向的内存被映射给一个结构体实例header
* ShapefileHeader header = (ShapefileHeader)Marshal.PtrToStructure
* (handle.AddrOfPinnedObject(), typeof(ShapefileHeader));
* handle.Free(); //释放内存 将其还给C#管理
* return header;
*/
return((ShapefileHeader)GISTools.FromBytes(br, typeof(ShapefileHeader)));
}
public static GISLayer ReadFile(string filename)
{
FileStream fsr = new FileStream(filename, FileMode.Open);
BinaryReader br = new BinaryReader(fsr);
MyFileHeader mfh = (MyFileHeader)(GISTools.FromBytes(br, typeof(MyFileHeader))); //读取文件头
SHAPETYPE ShapeType = (SHAPETYPE)Enum.Parse(typeof(SHAPETYPE), mfh.Shapetype.ToString()); //获取空间实体类型shapetype和
GISExtent Extent = new GISExtent(mfh.MinX, mfh.MaxX, mfh.MinY, mfh.MaxY); //地图范围extent
string layername = GISTools.ReadString(br); //读取图层名
List <GISField> Fields = ReadFields(br, mfh.FieldCount); //读取字段信息
GISLayer layer = new GISLayer(layername, ShapeType, Extent, Fields);
ReadFeatures(layer, br, mfh.FeatureCount);
br.Close();
fsr.Close();
return(layer);
}
