pb9升级到12.1后读卡器报错_PB

pb9升级到12.1后读卡器出错！
如题，怎么办


//9.0中声明外部函数,调用时成功返回0
//寻卡后选卡
function long rf_select(uint icdev,ref string pSnr,char srcLen,ref char Size) library "MasterRD.dll"
//12.1中声明用上面的失败，用下面的也失败，返回234
function long rf_select(uint icdev,ref string pSnr,char srcLen,ref char Size) library "MasterRD.dll" alias for "rf_select;Ansi"

------解决方案--------------------
把string 改成byte数组试试
------解决方案--------------------
//9.0中声明外部函数,调用时成功返回0//寻卡后选卡function long rf_select(uint icdev,ref string pSnr,char srcLen,ref char Size) library "MasterRD.dll"//12.1中声明用上面的失败，用下面的也失败，返回234
function long rf_select(uint icdev,ref string pSnr,char srcLen,ref char Size) library "MasterRD.dll" alias for "rf_select;Ansi"

试试声明如下：

function long rf_select(uint icdev,ref string pSnr,char srcLen,ref char Size) library "MasterRD.dll" //不加ansi试试
------解决方案--------------------
不用byte 用blob也可以试一下
Blob ( text {, encoding} )

Argument Description
text The string you want to convert to a blob datatype
encoding Character encoding of the resulting blob. Values are:?EncodingANSI!?EncodingUTF8!?EncodingUTF16LE! (default)?EncodingUTF16BE!