[英]Inference of second generic argument
我有如下類結構:
public interface IBinder<T>
where T : Control
{
T Control { get; }
}
public class ButtonBinder : IBinder<Button>
{
public ButtonBinder(Button control)
{
Control = control ?? throw new ArgumentNullException(nameof(control));
}
public Button Control { get; private set; }
}
在這樣的工廠方法的幫助下,創建我想要的那個 Binder 的實例:
public void Main()
{
// This line works.
var binder = RegisterBinder<ButtonBinder, Button>(new Button());
// But I want use type inference like this:
var binder2 = RegisterBinder<ButtonBinder>(new Button());
}
/// <summary>
/// My pseudo-factory.
/// </summary>
public T_Binder RegisterBinder<T_Binder, T_Control>(T_Control control)
where T_Binder : IBinder<T_Control>
where T_Control : Control
{
return (T_Binder)Activator.CreateInstance(typeof(T_Binder), control);
}
因為“ButtonBinder”類聲明了通用控件類型“Button”,編譯器應該能夠推斷出它。 如何告訴編譯器我想使用類型推斷?
謝謝你。
不幸的是,C# 不能僅推斷多個泛型參數之一。 但是,如果您不介意在中間類中捕獲可推斷類型,您可以執行以下操作:
public class Factory
{
public void Main()
{
// This line works.
var binder = RegisterBinder<ButtonBinder, Button>(new Button());
// Now only T_Binder is needed
var binder2 = ForControl(new Button()).RegisterBinder<ButtonBinder>();
}
private BinderRegistration<T_Control> ForControl<T_Control>(T_Control control) where T_Control : Control
{
return new BinderRegistration<T_Control>(control);
}
/// <summary>
/// My pseudo-factory.
/// </summary>
public T_Binder RegisterBinder<T_Binder, T_Control>(T_Control control)
where T_Binder : IBinder<T_Control>
where T_Control : Control
{
return (T_Binder)Activator.CreateInstance(typeof(T_Binder), control);
}
}
internal class BinderRegistration<T_Control>
where T_Control : Control
{
private readonly Control _control;
public BinderRegistration(Control control)
{
_control = control;
}
public T_Binder RegisterBinder<T_Binder>()
where T_Binder : IBinder<T_Control>
{
return (T_Binder)Activator.CreateInstance(typeof(T_Binder), _control);
}
}
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.