How to use VC++ code in C# windows application

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Hello all

I am using EPSON printer for passbook printing and barcode reading.

from many days i am trying to add the VC++ dll functionality(dll given by epson) to c# by help of one document,but i am not able to get it.

Now i am feeling i am going some where wrong.

Bwlow is one of the dll methods

DWORD WINAPI PrtOpen(LPCSTR lpszPortName)
Description:
The function opens the communication port.
Parameters:
lpszPortName is a string representing the name of the communication channel.
ex. "COM1", "USB001", "LPT1"
Return values:
PRT_SUCCESS if the port is not yet open and there are no errors.
PRT_ERR_ALREADY_OPEN if the port has already been opened with this function.

This is how i tried

C#

[DllImport(@"C:\Documents and Settings\Administrator\My Documents\visual studio 2010\Projects\TestClass\TestClass\PLQ20W32.dll", EntryPoint = "PrtBarRead")]
        private static extern string PrtOpen(string PortName);

But i am not able to make it work.

Please tell me the correct way to do it.
I have to finish my project soon.Please help.

Posted 26-May-14 1:29am

Snehasish_Nandy

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Comments

[no name] 26-May-14 7:37am

PrtOpen does not return a string.

[no name] 26-May-14 7:42am

Please tell me the correct way to call it..

[no name] 26-May-14 7:46am

Do you not know the difference between data types? Do you think that the DWORD being returned by PrtOpen is the same as a string in .NET?

[no name] 26-May-14 7:48am

That's why i am asking that please tell me the correct way to call..i am going in a wrong way all to gather.

[no name] 26-May-14 8:24am

Then I would suggest that you get a basic primer on programming and work through it. If you don't know the difference between an integer and a string then you are going to have nothing but trouble.

[no name] 26-May-14 11:08am

See vc++ is very much new for me.so what is the way of conversion i don't have idea.we are here to help..
Thanks for your suggestion but it would be more appreciated if you also help in the thing which is asked .

_Asif_ 26-May-14 8:09am

I am sure the Epson also have given a sample application as well to show how to use this dll. If not then ask Epson to sure the sample solution.

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_Asif_ · Answer 1 · 2014-05-26T02:16:00

Solution 1

Your definition seems wrong. use below definition and try again.

C#

[DllImport(@"C:\Documents and Settings\Administrator\My Documents\visual studio 2010\Projects\TestClass\TestClass\PLQ20W32.dll", EntryPoint = "PrtBarRead")]
        private static extern UInt32 PrtOpen(string PortName);

Posted 26-May-14 2:16am

_Asif_

Comments

[no name] 26-May-14 11:06am

Thanks..i will check and let u know..

[no name] 26-May-14 23:26pm

I wrote the way u told, but when the control is coming to the method it's redirecting to the disassembly page..