How to close & clear the OLEDBConnection on Form()_Load?

Hi,
I am using vs-2015. Managed C++/Cli Windows Forms Applications. I have Form1-MdiContainer & Form2. From Form1_Button_Click() accessing Form2.
In Form2_Load() I have OLEDBConnection. For When I press Form1-Button_Click(),
First time it's working good. Also when I re-click() the same Form1-Button()
the whole application is getting closed. I analysed that when I close the OLEDBConnection, the whole program is also getting closed. And the same code working good in c#. I can't understand my mistakes..! Thanks.

Note:- For First time when I click the Form1-Button no problem it's working good. But for re-click() whole application is getting closed().
Thanks Again

Code:

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My Codes
Form1-MdiContainer()
private: System::Void button1_Click(System::Object^  sender, System::EventArgs^  e) {
        Form2^ MyStForm = Form2::GetForm(true, this);
        MyStForm->MdiParent = this;
        MyStForm->FormBorderStyle = System::Windows::Forms::FormBorderStyle::None;
        MyStForm->Dock = DockStyle::Fill;
        MyStForm->Show();
}

Form2-Top side
        public ref class Form2 : public System::Windows::Forms::Form
        {
                public: static Form2^ Form2::_instance = nullptr;
                public:        static Form2^ Form2::GetForm(bool IsMDIChild, System::Windows::Forms::Form^ MyInstFrm) {
                        if (_instance == nullptr)
                                _instance = gcnew Form2();

                        if (_instance->IsDisposed)
                                _instance = gcnew Form2();

                        if (IsMDIChild)
                                _instance->MdiParent = MyInstFrm;

                        return _instance;
                }
                blah..blah...blah...
        }


Form2-Load()
private: System::Void Form2_Load(System::Object^  sender, System::EventArgs^  e) {
        String^ MyStrConn = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + MyExcelFile + "; Extended Properties=\"Excel 12.0; HDR=YES; OLE DB Services=-1; \"";
        String^ MyExcelFile="C:\\Students\\Names.xlsx";
        String^ MyExcelSheet = "[Sheet1$]";
        String^ MySQLSelect = "select * from " + MyExcelSheet;
        System::Data::OleDb::OleDbConnection^ Cn1 = nullptr;
        Cn1 = gcnew System::Data::OleDb::OleDbConnection();
        Cn1->ConnectionString = MyStrConn;
        System::Data::OleDb::OleDbCommand^ MyCmd = nullptr;
        MyCmd = gcnew System::Data::OleDb::OleDbCommand();
        MyCmd->CommandText = MySQLSelect;
        MyCmd->Connection = Cn1;
        Cn1->Open();
                System::Data::OleDb::OleDbDataAdapter^ Da1 = gcnew System::Data::OleDb::OleDbDataAdapter(MyCmd);
                Da1->Fill(MyDataTable);
        Cn1->Close(); //????????????????? getting stuck
        if (Cn1 != nullptr){
                MyCmd->Cancel();
        }
        //Cn1->ConnectionString = nullptr;
        //Cn1->ReleaseObjectPool();
        MyCmd = nullptr;
        Cn1 = nullptr;

}

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Thanks