.net - 为什么 DialogResult::Yes 需要一个::？

Question

为什么这样做:

using namespace System;
using namespace System::Windows::Forms;
...
if( MessageBox::Show("Really do it?", "Are you sure?", System::Windows::Forms::MessageBoxButtons::YesNo) == System::Windows::Forms::DialogResult::Yes )
{
    Console::WriteLine("Do it!");
}

..当失败时:

using namespace System;
using namespace System::Windows::Forms;
...
if( MessageBox::Show("Really do it?", "Are you sure?", System::Windows::Forms::MessageBoxButtons::YesNo) == DialogResult::Yes )
{
    Console::WriteLine("Do it!");
}

...出现以下错误:

error C2039: 'Yes' : is not a member of 'System::Windows::Forms::Form::DialogResult'

我假设 Visual Studio 正在获取 DialogResult 但我看不到它在哪里找到它？

Answer 1

System::Windows::Forms::Form 有一个名为 DialogResult 的属性(类型为 System::Windows::Forms::DialogResult)，因此错误。

http://msdn.microsoft.com/library/system.windows.forms.form.dialogresult.aspx

http://msdn.microsoft.com/library/system.windows.forms.dialogresult.aspx