C++: Windows Form unable to run char loop for string in textbox

I am trying to create a program that can translate normal characters to binary with interface included. But I happened to get an error that won't let the program compile.

Here is my code:

#pragma once

namespace Interface {

    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 std;

    /// <summary>
    /// Summary for MyForm
    /// </summary>
    public ref class MyForm : public System::Windows::Forms::Form
    {
    public:
        MyForm(void)
        {
            InitializeComponent();
            //
            //TODO: Add the constructor code here
            //
        }

    protected:
        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        ~MyForm()
        {
            if (components)
            {
                delete components;
            }
        }
    private: System::Windows::Forms::RichTextBox^  User_Input;
    protected:
    private: System::Windows::Forms::RichTextBox^  Binary_Output;
    private: System::Windows::Forms::Button^  Translate;
    private: System::Windows::Forms::Button^  Reset;

    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->User_Input = (gcnew System::Windows::Forms::RichTextBox());
            this->Binary_Output = (gcnew System::Windows::Forms::RichTextBox());
            this->Translate = (gcnew System::Windows::Forms::Button());
            this->Reset = (gcnew System::Windows::Forms::Button());
            this->SuspendLayout();
            // 
            // User_Input
            // 
            this->User_Input->Location = System::Drawing::Point(61, 31);
            this->User_Input->Name = L"User_Input";
            this->User_Input->Size = System::Drawing::Size(574, 185);
            this->User_Input->TabIndex = 0;
            this->User_Input->Text = L"";
            // 
            // Binary_Output
            // 
            this->Binary_Output->Location = System::Drawing::Point(61, 237);
            this->Binary_Output->Name = L"Binary_Output";
            this->Binary_Output->ReadOnly = true;
            this->Binary_Output->Size = System::Drawing::Size(574, 170);
            this->Binary_Output->TabIndex = 1;
            this->Binary_Output->Text = L"";
            // 
            // Translate
            // 
            this->Translate->Location = System::Drawing::Point(727, 108);
            this->Translate->Name = L"Translate";
            this->Translate->Size = System::Drawing::Size(148, 75);
            this->Translate->TabIndex = 2;
            this->Translate->Text = L"button1";
            this->Translate->UseVisualStyleBackColor = true;
            this->Translate->Click += gcnew System::EventHandler(this, &MyForm::Translate_Click);
            // 
            // Reset
            // 
            this->Reset->Location = System::Drawing::Point(727, 279);
            this->Reset->Name = L"Reset";
            this->Reset->Size = System::Drawing::Size(147, 68);
            this->Reset->TabIndex = 3;
            this->Reset->Text = L"button2";
            this->Reset->UseVisualStyleBackColor = true;
            this->Reset->Click += gcnew System::EventHandler(this, &MyForm::Reset_Click);
            // 
            // MyForm
            // 
            this->AutoScaleDimensions = System::Drawing::SizeF(6, 13);
            this->AutoScaleMode = System::Windows::Forms::AutoScaleMode::Font;
            this->ClientSize = System::Drawing::Size(908, 441);
            this->Controls->Add(this->Reset);
            this->Controls->Add(this->Translate);
            this->Controls->Add(this->Binary_Output);
            this->Controls->Add(this->User_Input);
            this->Name = L"MyForm";
            this->Text = L"MyForm";
            this->ResumeLayout(false);

        }
#pragma endregion
    private: System::Void Reset_Click(System::Object^  sender, System::EventArgs^  e) {
        User_Input->ResetText();
        Binary_Output->ResetText();
    }
    private: System::Void Translate_Click(System::Object^  sender, System::EventArgs^  e) {

        String ^ UserInput;
        UserInput = User_Input->Text;

        for (char x : UserInput) {
            String binary = UserInput->ToString;
        }

    }
};
}

Here is my error:

myform1.h(124): error C3312: no callable 'begin' function found for type 'System::String ^'
myform1.h(124): error C3312: no callable 'end' function found for type 'System::String ^'
myform1.h(125): error C3149: 'System::String': cannot use this type here without a top-level '^'
myform1.h(125): error C3867: 'System::String::ToString': non-standard syntax; use '&' to create a pointer to member

First time learning about Windows Form so still unfamiliar to it. Hope to get some advice on how to improve the code and what should I be careful next time I try to make a program.