C++/CLI - how to open a new form and back - winforms

Question

I am creating an application where the front end has to be a Windows Form using C++/CLI. The form is used for login purpose.
In my form, I have a register button. On click of this button, a new form should open ( closing the login form ). I was able to achieve this by the following code:
Form^ rgForm = gcnew RegisterForm;
rgForm->Show();
this->Hide(); // using this->Close() was closing the application
Now I want to have a cancel button on the register form, whose click should open the login form again and close the register form. How do I achieve that?
( I am confused with the use of this->Hide(), does it mean that the form exists, we just did not show it, and so even after the register form visibility, the login form still exists? )
Update : Now current form handle is passed into register form constructor ( storing it as a private variable with the name loginForm in RegisterForm class ).
Following is the code for cancel button click:
// RegisterForm class constructor
RegisterForm(System::Windows::Forms::Form^ f)
{
loginForm = f;
}
// Cancel button click
private: System::Void BtnCancel_Click(System::Object^ sender, System::EventArgs^ e)
{
loginForm->Show();
this->Hide();
}
On cancel button click I am getting the exception : "object not set to instance".
Can someone please help me.
Thanks.

Answer 1

Create a constructor for RegisterForm which accepts a System::Windows::Form ^ object, and pass this to it when you are instantiating it from within the login form class
Form^ rgForm = gcnew RegisterForm(this);
rgForm->Show();
this->Hide();
Assume the login form object is called otherform within the RegisterForm class. Once you're ready to bring it back, just call otherform->Show()
When you hide the form, it still exists, it is just not visible to the user.
EDIT: I got this to work just fine. Here are the modifications (not the full code) that I made to the form
Form2(Registration form)
Form2(System::Windows::Forms::Form ^ frm1)
{
otherform = frm1;
InitializeComponent();
}
private: System::Windows::Forms::Form ^ otherform;
private: System::Void Cancel_Click(System::Object^ sender, System::EventArgs^ e) {
this->Hide();
otherform->Show();
}
Form1(Login form)
#include "Form2.h"
private: System::Void Register_Click(System::Object^ sender, System::EventArgs^ e) {
Form2 ^ frm2 = gcnew Form2(this);
frm2->Show();
this->Hide();
}

Answer 2

Thereby , I would like to show my full code to help the others:-
Form2.h
#pragma once
using namespace System;
using namespace System::ComponentModel;
using namespace System::Collections;
using namespace System::Windows::Forms;
using namespace System::Data;
using namespace System::Drawing;
namespace Form1 {
/// <summary>
/// Summary for Form2
/// </summary>
public ref class Form2 : public System::Windows::Forms::Form
{
private: System::Windows::Forms::Form ^ otherform;
public:
Form2(System::Windows::Forms::Form ^ o )
{
otherform = o;
InitializeComponent();
//
//TODO: Add the constructor code here
//
}
protected:
/// <summary>
/// Clean up any resources being used.
/// </summary>
~Form2()
{
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(147, 132);
this->button1->Name = L"button1";
this->button1->Size = System::Drawing::Size(102, 38);
this->button1->TabIndex = 0;
this->button1->Text = L"Menu";
this->button1->UseVisualStyleBackColor = true;
this->button1->Click += gcnew System::EventHandler(this, &Form2::button1_Click);
//
// Form2
//
this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
this->ClientSize = System::Drawing::Size(412, 295);
this->Controls->Add(this->button1);
this->Name = L"Form2";
this->Text = L"Form2";
this->Load += gcnew System::EventHandler(this, &Form2::Form2_Load);
this->ResumeLayout(false);
}
#pragma endregion
private: System::Void Form2_Load(System::Object^ sender, System::EventArgs^ e) {
}
private: System::Void button1_Click(System::Object^ sender, System::EventArgs^ e) {
this->Hide();
otherform->Show();
}
};
////////////////////////
}

Answer 3

///////////////////////Form1.h
#pragma once
#include "stdafx.h"
#include "Form2.h"
namespace Form1 {
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
/// </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(140, 206);
this->button1->Name = L"button1";
this->button1->Size = System::Drawing::Size(75, 23);
this->button1->TabIndex = 0;
this->button1->Text = L"Login";
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(377, 291);
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) {
Form2 ^ frm2 = gcnew Form2(this);
frm2->Show();
this->Hide();
}
};
}