Go4Expert - Error: cannot convert from (__clrcall *) to (_

I am compiling in Visual C++ 2005 Express Edition.

I am getting the following error:

error C2440: '=' : cannot convert from 'void (__clrcall sept05::Form1::* )(pjsua_call_id)' to 'void (__cdecl *)
(pjsua_call_id)'

Please help. Thanks.

Following is the code that is causing the error:
Code:
#pragma once

 

#include "pjsua-lib/pjsua.h"

 

namespace sept05 {

using namespace System;

using namespace System::ComponentModel;

using namespace System::Collections;

using namespace System::Windows::Forms;

using namespace System::Data;

using namespace System::Drawing;

/// <summary>

/// Summary for Form1

///

/// WARNING: If you change the name of this class, you will need to change the

/// 'Resource File Name' property for the managed resource compiler tool

/// associated with all .resx files this class depends on. Otherwise,

/// the designers will not be able to interact properly with localized

/// resources associated with this form.

/// </summary>

public ref class Form1 : public System::Windows::Forms::Form

{

public:

Form1(void)

{

InitializeComponent();

//

//TODO: Add the constructor code here

//

}

protected:

/// <summary>

/// Clean up any resources being used.

/// </summary>

~Form1()

{

if (components)

{

delete components;

}

}

private: System::Windows::Forms::Button^ button1;

protected: 

private:

/// <summary>

/// Required designer variable.

/// </summary>

System::ComponentModel::Container ^components;

#pragma region Windows Form Designer generated code

/// <summary>

/// Required method for Designer support - do not modify

/// the contents of this method with the code editor.

/// </summary>

void InitializeComponent(void)

{

this->button1 = (gcnew System::Windows::Forms::Button());

this->SuspendLayout();

// 

// button1

// 

this->button1->Location = System::Drawing::Point(173, 124);

this->button1->Name = L"button1";

this->button1->Size = System::Drawing::Size(75, 23);

this->button1->TabIndex = 0;

this->button1->Text = L"button1";

this->button1->UseVisualStyleBackColor = true;

this->button1->Click += gcnew System::EventHandler(this, &Form1::button1_Click);

// 

// Form1

// 

this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);

this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;

this->ClientSize = System::Drawing::Size(284, 262);

this->Controls->Add(this->button1);

this->Name = L"Form1";

this->Text = L"Form1";

this->ResumeLayout(false);

}

#pragma endregion

private: System::Void button1_Click(System::Object^ sender, System::EventArgs^ e) {



pj_status_t status;

pjsua_acc_id acc_id;

 

status = pjsua_create();

{

pjsua_config cfg;

pjsua_config_default(&cfg);

cfg.cb.on_call_media_state = &on_call_media_state;    //this line is creating error

 

status = pjsua_init(&cfg, NULL, NULL);

}



{

pjsua_transport_config cfg;

pjsua_transport_config_default(&cfg);

cfg.port = 5060;

status = pjsua_transport_create(PJSIP_TRANSPORT_UDP, &cfg, NULL);



}



status = pjsua_start();



{

pjsua_acc_config cfg;



pjsua_acc_config_default(&cfg);

cfg.id = pj_str("sip:abc@1.1.1.1");

cfg.reg_uri = pj_str("sip:1.1.1.1");

cfg.cred_count = 1;

cfg.cred_info[0].realm = pj_str("aaa");

cfg.cred_info[0].scheme = pj_str("digest");



cfg.cred_info[0].username = pj_str("abc");

cfg.cred_info[0].data_type = PJSIP_CRED_DATA_PLAIN_PASSWD;

cfg.cred_info[0].data = pj_str("abc");

 



status = pjsua_acc_add(&cfg, PJ_TRUE, &acc_id);

 

 



}

 

 

 

}



// Callback called by the library when call's media state has changed 

private: static void on_call_media_state(pjsua_call_id call_id)

{

pjsua_call_info ci;



pjsua_call_get_info(call_id, &ci);

if (ci.media_status == PJSUA_CALL_MEDIA_ACTIVE) {

// When media is active, connect call to sound device.

pjsua_conf_connect(ci.conf_slot, 0);

pjsua_conf_connect(0, ci.conf_slot);

}

}

 

};

}