TPVPC: C# Integration

Integrating Get Central in a .NET environment is performed through Platform Invocation Services (P/Invoke), allowing managed C# code to call the native Get Central library. This guide explains how to configure your project, declare the native functions, and execute a basic payment operation.

This guide applies to TpvpcImplantado.

This integration model applies to TpvpcImplantado.

Requirements

Before you begin, ensure you have:

• dllTpvpcLatente.dll available at runtime
• All required native dependencies present in the same directory
• Visual Studio or another .NET-compatible IDE
• Project Target Platform set to x86 (the library is 32-bit)

Failure to compile or run in x86 mode will result in a BadImageFormatException.

C-Sharp Integration Process

The integration process consists of mapping the native library functions and invoking them from managed code. No XML is sent as a request; parameters are passed positionally, and the XML is returned as a response.

Step 1: Declare Native Functions

Native functions are declared using the DllImport attribute. The library exposes a fixed set of entry points that must be mapped exactly.

Library Initialization

The following functions are used to initialize the library:

[DllImport("dllTpvpcLatente.dll", CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Ansi)]
public static extern int fnDllIniTpvpcLatente(
    string cComercio,
    string cTerminal,
    string cClaveFirma,
    string cConfPuerto,
    string cVersion
);

Payment Execution

The following functions are used to execute a payment operation:

[DllImport("dllTpvpcLatente.dll", CallingConvention = CallingConvention.StdCall, CharSet = CharSet.Ansi)]
public static extern int fnDllOperPinPad(
    string cImporte,
    string cFactura,
    string cTipoOper,
    StringBuilder cXMLResp,
    int iTamMaxResp
);

Library Finalization

The following functions are used to finalize the library:

[DllImport("dllTpvpcLatente.dll", CallingConvention = CallingConvention.StdCall)]
public static extern int fnDllParaTpvpcLatente();

Step 2: Initialize the Library

Before executing any transaction, the library must be initialized once per application lifecycle.

int result = fnDllIniTpvpcLatente(
    "99999999",
    "00000001",
    "CLAVE123456",
    "",
    ""
);

if (result != 0)
{
    // Initialization failed. Do not proceed.
}

A return value of 0 indicates successful initialization.

Step 3: Execute a Payment Operation

Once initialized, a standard card-present payment can be executed using cTipoOper = "PAGO".

StringBuilder xmlResponse = new StringBuilder(8192);

int result = fnDllOperPinPad(
    "1.00",
    "TEST0001",
    "PAGO",
    xmlResponse,
    xmlResponse.Capacity
);

When the function returns, the XML response buffer is populated with the transaction result.

Step 4: Process the Response

The integer return value indicates only the technical execution status. The financial outcome must be determined by parsing the XML response.

A transaction is authorized only if the response contains:

<estado>F</estado>
<resultado>Autorizada</resultado>

Any other combination must be treated as a denied transaction.

Step 5: Finalize the Library

When the application no longer needs to perform operations, the library should be finalized to release system resources.

fnDllParaTpvpcLatente();

Next Steps

After completing the C# integration, you can proceed with further implementation:

• To process standard payments, refer to the Process a Single-Step Payment guide.
• For details on generating and printing receipts, see the Generate and Print Receipts documentation.
• To implement subscription models, consult the Handle Recurring Payments guide.
• For a complete reference of technical exit codes and host errors, refer to the Result Codes and Errors documentation.