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Using a textbox and other items between multiple forms

ComplexComponent453 (8)
Hello, I am writing a program in Visual C++ 10 with 2 forms.

In the first form I have a textbox and a button.
The button opens the second form.

In the second form, I have a button that changes the text in the textbox in form1 to an item from a listbox in form2.

Here is my problem. When I do the code for the button in form2 to change the textbox in form1 I get the errors:

error C2065: 'textBox1' : undeclared identifier
error C2227: left of '->Text' must point to class/struct/union/generic type


I thought maybe I should just include the "Form1.h" file but I can't do that because I already included "Form2.h" in form1 in order to be able to open the second form. If I try to include form1 in form2, it says that the code to open form2 is an error now.

My question is, how can I access identifiers such as "textbox1" from other forms and other files when I already used the first form to open the second form? I also want to know how to do this for all identifiers between all files.

One more question is how to print the selecteditem from a listbox into a textbox because that doesn't work by just setting them equal either.

Thank you. Here is my code:

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#pragma once
#include "Form2.h"

namespace Test1 {

	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: System::Windows::Forms::TextBox^  textBox1;

	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->textBox1 = (gcnew System::Windows::Forms::TextBox());
			this->SuspendLayout();
			// 
			// button1
			// 
			this->button1->Location = System::Drawing::Point(155, 60);
			this->button1->Name = L"button1";
			this->button1->Size = System::Drawing::Size(100, 23);
			this->button1->TabIndex = 0;
			this->button1->Text = L"Second Form";
			this->button1->UseVisualStyleBackColor = true;
			this->button1->Click += gcnew System::EventHandler(this, &Form1::button1_Click);
			// 
			// textBox1
			// 
			this->textBox1->Location = System::Drawing::Point(155, 124);
			this->textBox1->Multiline = true;
			this->textBox1->Name = L"textBox1";
			this->textBox1->Size = System::Drawing::Size(100, 45);
			this->textBox1->TabIndex = 1;
			// 
			// Form1
			// 
			this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
			this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
			this->ClientSize = System::Drawing::Size(386, 227);
			this->Controls->Add(this->textBox1);
			this->Controls->Add(this->button1);
			this->Name = L"Form1";
			this->Text = L"Form1";
			this->ResumeLayout(false);
			this->PerformLayout();

		}
#pragma endregion
	private: System::Void button1_Click(System::Object^  sender, System::EventArgs^  e) {
			Form2^ frm = gcnew Form2;
			frm->Show(this);
			 }
	};
}



Form2.h

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#pragma once

namespace Test1 {

	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 Form2
	/// </summary>
	public ref class Form2 : public System::Windows::Forms::Form
	{
	public:
		Form2(void)
		{
			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^  button2;
	protected: 
	private: System::Windows::Forms::ListBox^  listBox1;

	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->button2 = (gcnew System::Windows::Forms::Button());
			this->listBox1 = (gcnew System::Windows::Forms::ListBox());
			this->SuspendLayout();
			// 
			// button2
			// 
			this->button2->Location = System::Drawing::Point(75, 152);
			this->button2->Name = L"button2";
			this->button2->Size = System::Drawing::Size(140, 51);
			this->button2->TabIndex = 0;
			this->button2->Text = L"Add";
			this->button2->UseVisualStyleBackColor = true;
			this->button2->Click += gcnew System::EventHandler(this, &Form2::button2_Click);
			// 
			// listBox1
			// 
			this->listBox1->FormattingEnabled = true;
			this->listBox1->Items->AddRange(gcnew cli::array< System::Object^  >(3) {L"Option 1", L"Option 2", L"Option 3"});
			this->listBox1->Location = System::Drawing::Point(84, 32);
			this->listBox1->Name = L"listBox1";
			this->listBox1->Size = System::Drawing::Size(120, 95);
			this->listBox1->TabIndex = 1;
			// 
			// Form2
			// 
			this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
			this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
			this->ClientSize = System::Drawing::Size(284, 261);
			this->Controls->Add(this->listBox1);
			this->Controls->Add(this->button2);
			this->Name = L"Form2";
			this->Text = L"Form2";
			this->ResumeLayout(false);

		}
#pragma endregion
	private: System::Void button2_Click(System::Object^  sender, System::EventArgs^  e) {
				textBox1 -> Text = listBox1 -> SelectedItem;
				Close();
			 }
	};
}

Albatross (4553)
Line 93: I can't particularly say that you have declared a textBox1 in Form2. You'll need to find some other way to access it (maybe include a getter in Form1 and have some way for Form2 to have a reference/pointer to the instance of Form1 that created it?)

-Albatross
naraku9333 (2163)
Maybe overload the Form2 constructor to take a Textbox^
ComplexComponent453 (8)
That was my question, how to I refer to the textbox that was created in Form1 from another form.
Albatross (4553)
naraku9333 actually offered a good solution. Have an overloaded constructor for Form2 that takes a Textbox^, pass in your textBox1, and store the reference somewhere.

-Albatross
ComplexComponent453 (8)
How would I go about doing that?
naraku9333 (2163)
I don't use c++cli often but something like...

Form2:
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public:
		Form2(void)
		{
			InitializeComponent();
			//
			//TODO: Add the constructor code here
			//
		}
		Form2(System::Windows::Forms::Textbox^ tb) : textBox1(tb)
		{
			InitializeComponent();
		}
		private: System::Windows::Forms::TextBox^  textBox1;



Form1:
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private: System::Void button1_Click(System::Object^  sender, System::EventArgs^  e) {
			Form2^ frm = gcnew Form2(textBox1);
			frm->Show(this);
			 }
	};
ComplexComponent453 (8)
I tried to do that but I just get a bunch of errors.

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public: 
	Form2(void)
	{
		InitializeComponent();
		TextBox^ tb = gcnew TextBox;
	}
	Form2(System::Windows::Forms::TextBox^ tb) : textBox1(tb)
	{
		InitializeComponent();
	}
	private: System::Windows::Forms::TextBox^  textBox1;



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error C2059: syntax error : 'public'
error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
error C3861: 'InitializeComponent': identifier not found
warning C4508: 'Test1::Form2' : function should return a value; 'void' return type assumed
error C2550: 'Test1::Form2' : constructor initializer lists are only allowed on constructor definitions
error C3861: 'InitializeComponent': identifier not found
error C2059: syntax error : 'private'
error C3145: 'textBox1' : global or static variable may not have managed type 'System::Windows::Forms::TextBox ^'


The original show() function stopped working in form 1 aswell
naraku9333 (2163)
Where did you add that code? Can you upload the project some where so I can run it and see what is going on?
ComplexComponent453 (8)
I coded it so all of the errors are gone and I can at least get the program running. I made the button in form2 do set the text for the rich text box in form1. The only problem I have now is I get a runtime error popup that says:

"An unhandled exception of type 'System.NullReferenceException' occurred in Test1.exe

Additional information: Object reference not set to an instance of an object."

This popup comes up when I click "button2" in form2. This is the button that sets the text of the textbox in form1.

Here is my exact code from my files:
The code that I put in from you are in lines 19-27 in Form2.h
The rest is there as well for looking over it all.
Thank you for all of your help.


Form1.h

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#pragma once
#include "Form2.h"

namespace Test1 {

	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;
	private: System::Windows::Forms::RichTextBox^  richTextBox1;
	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->richTextBox1 = (gcnew System::Windows::Forms::RichTextBox());
			this->SuspendLayout();
			// 
			// button1
			// 
			this->button1->Location = System::Drawing::Point(120, 41);
			this->button1->Name = L"button1";
			this->button1->Size = System::Drawing::Size(100, 23);
			this->button1->TabIndex = 0;
			this->button1->Text = L"Second Form";
			this->button1->UseVisualStyleBackColor = true;
			this->button1->Click += gcnew System::EventHandler(this, &Form1::button1_Click);
			// 
			// richTextBox1
			// 
			this->richTextBox1->Location = System::Drawing::Point(120, 89);
			this->richTextBox1->Name = L"richTextBox1";
			this->richTextBox1->Size = System::Drawing::Size(100, 96);
			this->richTextBox1->TabIndex = 1;
			this->richTextBox1->Text = L"";
			// 
			// Form1
			// 
			this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
			this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
			this->ClientSize = System::Drawing::Size(386, 227);
			this->Controls->Add(this->richTextBox1);
			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^ frm = gcnew Form2(richTextBox1);
			frm->Show(this);
			 }
	};
}



Form2.h

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#pragma once

namespace Test1 {

	using namespace System;
	using namespace System::ComponentModel;
	using namespace System::Collections;
	using namespace System::Windows::Forms;
	using namespace System::Data;
	using namespace System::Drawing;
	using namespace Test1;

	/// <summary>
	/// Summary for Form2
	/// </summary>
	public ref class Form2 : public System::Windows::Forms::Form
	{
	public:
		Form2(void)
		{
			InitializeComponent();
			RichTextBox^ rtb = gcnew RichTextBox;
		}
		Form2(System::Windows::Forms::RichTextBox^ richTextBox1)
		{
			InitializeComponent();
		}
	private: System::Windows::Forms::RichTextBox^ richTextBox1;

	protected:
		/// <summary>
		/// Clean up any resources being used.
		/// </summary>
		~Form2()
		{
			if (components)
			{
				delete components;
			}
		}
	private: System::Windows::Forms::Button^  button2;
	protected: 


	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->button2 = (gcnew System::Windows::Forms::Button());
			this->SuspendLayout();
			// 
			// button2
			// 
			this->button2->Location = System::Drawing::Point(68, 66);
			this->button2->Name = L"button2";
			this->button2->Size = System::Drawing::Size(140, 124);
			this->button2->TabIndex = 0;
			this->button2->Text = L"Add";
			this->button2->UseVisualStyleBackColor = true;
			this->button2->Click += gcnew System::EventHandler(this, &Form2::button2_Click);
			// 
			// Form2
			// 
			this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
			this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
			this->ClientSize = System::Drawing::Size(284, 261);
			this->Controls->Add(this->button2);
			this->Name = L"Form2";
			this->Text = L"Form2";
			this->ResumeLayout(false);

		}
#pragma endregion
	private: System::Void button2_Click(System::Object^  sender, System::EventArgs^  e) {
				richTextBox1 -> Text = "This is a test";
				Close();
			 }
	};
}

naraku9333 (2163)
Form2
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Form2(void)
{
	InitializeComponent();
	RichTextBox^ rtb = gcnew RichTextBox;
}
Form2(System::Windows::Forms::RichTextBox^ richTextBox1)
{
	InitializeComponent();
}

should be
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Form2(void)
{
	InitializeComponent();
        richTextBox1 = gcnew RichTextBox;//init richTextBox1 here
}
Form2(System::Windows::Forms::RichTextBox^ rtb) 
    : richTextBox1(rtb)//and here
{
	InitializeComponent();
}
ComplexComponent453 (8)
It worked. Thank you so much for all of your help.

The only problem I had afterwards was the original text would erase and the location would be at the top corner of the screen. This was easily fixed because the textbox had its own settings in form2 that applied when the form opened so I just changed the settings and got rid of the text option. Now it works perfectly.

Thank you very much.
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