寫作和保存文本文件中的C++的Visual Studio

Question

所以這裏的這段代碼：

private: System::Void button1_Click(System::Object^ sender, System::EventArgs^ e) { 
       mn=textBox1->Text; 
       MessageBox::Show(mn+" "+tsk, "Info"); 
       String^ fileName = "records.txt"; 
       StreamWriter^ sw = gcnew StreamWriter("records.txt"); 
       sw->Write(mn,tsk); 
       sw->Close(); 
      } 

每次我嘗試寫一些新的東西到從程序文件，它只是寫入新的文本，不會保留舊。我怎樣才能保存它，所以它不會刪除？

Answer 1

StreamWriter constructor的文檔聲明您必須將append參數設置爲true以避免僅覆蓋該文件。您的代碼應該是：

private: System::Void button1_Click(System::Object^ sender, System::EventArgs^ e) { 
      mn=textBox1->Text; 
      MessageBox::Show(mn+" "+tsk, "Info"); 
      String^ fileName = "records.txt"; 
      StreamWriter^ sw = gcnew StreamWriter("records.txt", true); //append to file 
      sw->Write(mn,tsk); 
      sw->Close(); 
     }