c# - System.InvalidCastException：无法将“System.Object”类型的对象转换为“System.IO.StreamWriter”类型

Question

我试图将 Object 变量转换为 StreamWriter。但是，它不起作用。错误是什么？

StreamWriter file = (StreamWriter) myObject;

score 3 · Accepted Answer

3

的值myObject不是（可转换为）StreamWriter。

于 2013-11-06T18:49:55.773 回答

score 3 · Accepted Answer

试试这个：

if (myObject is StreamWriter) 
{
    var file = (StreamWriter) myObject as StreamWriter;
}

score 2 · Accepted Answer

2

于 2013-11-06T18:58:00.990 回答

score 1 · Accepted Answer

在转换之前，检查是否可以StreamWriter使用is关键字将其转换为对象，如下所示：

if(myObject is StreamWriter)
{
//can be cast
}
else
{
//can not be cast
}

4 回答 4