c# - 将 UserControl 转换为特定类型的用户控件

Question

有没有办法将用户控件转换为特定的用户控件，以便我可以访问它的公共属性？基本上我正在通过占位符的控件集合进行搜索，并且我正在尝试访问用户控件的公共属性。

foreach(UserControl uc in plhMediaBuys.Controls)
{
    uc.PulblicPropertyIWantAccessTo;
}

Answer 1

foreach(UserControl uc in plhMediaBuys.Controls) {
    MyControl c = uc as MyControl;
    if (c != null) {
        c.PublicPropertyIWantAccessTo;
    }
}

Answer 2

foreach(UserControl uc in plhMediaBuys.Controls)
{
  if (uc is MySpecificType)
  {
    return (uc as MySpecificType).PulblicPropertyIWantAccessTo;
  }
}

Answer 3

铸件

我更喜欢使用：

foreach(UserControl uc in plhMediaBuys.Controls)
{
    ParticularUCType myControl = uc as ParticularUCType;
    if (myControl != null)
    {
        // do stuff with myControl.PulblicPropertyIWantAccessTo;
    }
}

主要是因为使用 is 关键字会导致两次（准昂贵）强制转换：

if( uc is ParticularUCType ) // one cast to test if it is the type
{
    ParticularUCType myControl = (ParticularUCType)uc; // second cast
    ParticularUCType myControl = uc as ParticularUCType; // same deal this way
    // do stuff with myControl.PulblicPropertyIWantAccessTo;
}

参考

• C# 中的 3 个强制转换运算符
• C# 中类型转换对执行性能的影响