Shapelib--DBFReadStringAttribute

Shapefile C Library:    http://shapelib.maptools.org/

 

API使用：

1.SHP File API：    http://shapelib.maptools.org/shp_api.html

2.Attribute (.DBF) API:     http://shapelib.maptools.org/dbf_api.html

 

shapefile格式说明及读写代码示例:    http://www.gispower.org/article/arcgis/arcother/2008/48/0848115049GB922C13K2I22H7G06A4.html

 

问题：

在winform(c#)中使用maptools时，在研发机上程序运行正常，在测试机上程序闪退或报错。dubug发现问题出在函数DBFReadStringAttribute。

解决方案：

在stackoverflow上找到了解决方法。

问题链接：http://stackoverflow.com/questions/11860982/msvcr71-dll-crashing-iis-7-app-pool-on-windows-server-2008-w-asp-net-4/11875302#11875302

内容引用：

    Here's my original import:（原定义）

    [DllImport("shapelib.dll", CharSet = CharSet.Ansi)]
public static extern string DBFReadStringAttribute (IntPtr hDBF, int iShape, int iField);

   ...and here's what I had to change it to:（修改后定义）

    [DllImport("shapelib.dll", CharSet = CharSet.Ansi)]
public static extern IntPtr DBFReadStringAttribute (IntPtr hDBF, int iShape, int iField);

Here's what I ended up doing in the end...

public static string DBFReadStringAttribute(IntPtr hDBF, int iShape, int iField)
{
    IntPtr dataPtr = _DBFReadStringAttribute(hDBF, iShape, iField);
    string output = Marshal.PtrToStringAnsi(dataPtr, 255); //255 is the supposed max length for DBF databases
    int idx = output.IndexOf('\0');
    string strData;
    if (idx > 0)
        strData = output.Substring(0, idx).Trim();
    else
        strData = "";

    return strData;
}