[英]How to cast Object to its actual type and convert it?
如何将对象数量放入_StoredStock
? 数量是一个对象,我发现很难将其转换为int
以将值放入_StoredStock
。
class EachStock: Stock
{
public override void bookStock(Quantity quantity)
{
if (quantity.GetType() == typeof(EachStockQuantity))
{
//How to placethe object quantity into a _BookedStock
// the quantity is an object which I find it hard to convert it to int for _StoredStock
}
}
}
您正在尝试将类实例存储在整数变量中。 我认为部分问题在于参数名称具有误导性,因为它不是数量,而是具有 Quantity 属性的类。
访问您需要的属性,在本例中为Quantity
:
public override void AdjustStock(StockQuantity stockQty)
{
if (stockQty.GetType() == typeof(DiscreteStockQuantity))
_StoredStock = ((DiscreteStockQuantity)stockQty).Quantity;
}
或者,可能稍微更具可读性(但这是一个意见问题):
public override void AdjustStock(StockQuantity stockQty)
{
var discStockQty = stockQty as DiscreteStockQuantity;
if (discStockQty != null)
_StoredStock = discStockQty.Quantity;
}
有多种方法可以了解类型并进行实际转换。
这是一个懒惰的例子:
class Program
{
static void Main(string[] args)
{
object obj = new Foo();
Type objType = obj.GetType();
if(objType == typeof(Foo))
{
var foobar = (Foo)obj;
Console.WriteLine(foobar.Bar);
}
else if(objType == typeof(int))
{
// Do something
}
else
{
// Do something
}
// If you are brave enough you can use dynamic
dynamic bar = obj;
Console.WriteLine(bar.Bar);
Console.ReadLine();
}
}
class Foo
{
public string Bar { get; set; }
public Foo()
{
Bar = "FooBar";
}
}
这输出:
FooBar
FooBar
更新:
这是一个类似于您的问题的示例
class Program
{
static void Main(string[] args)
{
int i = FooBar(new Foo());
Console.WriteLine(i);
Console.ReadLine();
}
public static int FooBar(FooBase fooBase)
{
int val = -1;
Type type = fooBase.GetType();
if(type == typeof(Foo))
{
Foo foo = (Foo)fooBase;
val = foo.Bar;
}
else
{
// Do something
}
return val;
}
}
class Foo : FooBase
{
public int Bar { get; set; }
public Foo()
{
Bar = 999;
}
}
class FooBase
{
}
输出:
999
尝试这个:
public override void AdjustStock(StockQuantity quantity)
{
if (quantity is DiscreteStockQuantity)
{
var dq = quantity as DiscreteStockQuantity;
_StoredStock = dq.Quantity;
}
}
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