程序：通过点击按钮，上传本地图片到winform中显示，可以显示，但只要打开其他windows窗口，图片就消失了。具体代码如下，请高手答疑。 
private: System::Void 选择button3_Click(System::Object^ sender, System::EventArgs^ e) { 
this->openFileDialog1->ShowDialog(); 
Image^ image=gcnew Bitmap(openFileDialog1->FileName); 
Image^ pThumbnail = image->GetThumbnailImage(50, 50, nullptr, System::IntPtr::Zero); 
this->CreateGraphics()->DrawImage(pThumbnail,218,230,pThumbnail->Width,pThumbnail->Height); 
delete pThumbnail; 
}