Question

我正在尝试使用此代码关闭消息框特定答案的表单。我一直收到一条错误消息，指出Yes和No都不属于DialogResult::。我基本上直接从MS站点复制了这段代码，所以我不知道出了什么问题。帮助

private: System::Void Form1_FormClosing(System::Object^  sender, System::Windows::Forms::FormClosingEventArgs^  e) {
             if(!watchdog->Checked)
             {
                 if((MessageBox::Show("CAN Watchdog is currently OFF. If you exit with these settings, the SENSOWheel will still be engaged. To prevent this, please enable CAN Watchdog before closing. Would you still like to quit?", "Watchdog Warning", MessageBoxButtons::YesNo, MessageBoxIcon::Question) == DialogResult::No))
                 {
                     return;
                 }
                 else
                 {
                     close_Click(this, e);
                 }
             }

     }

Answer 1

if((MessageBox::Show("...", "Watchdog Warning", MessageBoxButtons::YesNo, MessageBoxIcon::Question) == 
    System::Windows::Forms::DialogResult::No))                  
{
   e->Cancel = true;    // don't close              
}

Answer 2

DialogResult枚举与DialogResult Form属性之间存在命名冲突。你想要前者，编译器假设你指的是后者。

解决歧义的一种方法是完全限定您对枚举的引用：

if((MessageBox::Show("CAN Watchdog ... Would you still like to quit?", "Watchdog Warning", MessageBoxButtons::YesNo, MessageBoxIcon::Question) == System::Windows::Forms::DialogResult::No))

我在thread找到了第二种方法;将using namespace System...语句移出namespace块，然后通过全局命名空间引用枚举。

if((MessageBox::Show("CAN Watchdog ... Would you still like to quit?", "Watchdog Warning", MessageBoxButtons::YesNo, MessageBoxIcon::Question) == ::DialogResult::No))

Answer 3

这是工作解决方案，它有一些额外的代码，所以你可以看到整个图片。在此示例中，有一些工作BackgroundWorker必须在应用程序关闭之前停止。

#pragma region Start/Stop/Exit

    private: System::Void backgroundWorker1_RunWorkerCompleted(System::Object^  sender, System::ComponentModel::RunWorkerCompletedEventArgs^  e) {
                 if(e->Cancelled)     
                 {
                     rtbLog->Text = rtbLog->Text  +  ">>> Application stopped \n";  
                 }
                 else   
                 {
                     rtbLog->Text = rtbLog->Text  +  ">>> Application completed \n";  
                 }
             }

    private: System::Void startToolStripMenuItemStart_Click(System::Object^  sender, System::EventArgs^  e) 
             {
                 if (backgroundWorker1->IsBusy == false) 
                 { 
                     backgroundWorker1->RunWorkerAsync(1);  //starting background worker
                 }
             }

    private: System::Void stopToolStripMenuItemStop_Click(System::Object^  sender, System::EventArgs^  e) 
             {
                 if (backgroundWorker1->IsBusy == true && backgroundWorker1->WorkerSupportsCancellation == true) 
                 {     
                     backgroundWorker1->CancelAsync(); 
                 } 
             }    

    private: System::Void Form1_FormClosing(System::Object^  sender, System::Windows::Forms::FormClosingEventArgs^  e) {

                 if((MessageBox::Show("Would you still like to quit?", "Warning", MessageBoxButtons::YesNo, MessageBoxIcon::Question) == 
                     System::Windows::Forms::DialogResult::No))                  
                 {
                     e->Cancel = true;    // Don't close and BackgroundWoker is executing.             
                 }  
                 else
                 {
                     if (backgroundWorker1->IsBusy == true && backgroundWorker1->WorkerSupportsCancellation == true) 
                     {     
                         backgroundWorker1->CancelAsync(); 
                     } 
                 } 
             }

    private: System::Void exitToolStripMenuItemExit_Click(System::Object^  sender, System::EventArgs^  e) {

                 Application::Exit(); // The user wants to exit the application. Close everything down.

             }

#pragma endregion

消息框上的关闭表单回答麻烦

3 个答案: