Question

这是我的代码：

using System.Reflection;
Public class ClassA
{
    public ClassA()
    {
        ClassB classB = new ClassB();
        classB.UsingType = "ClassD";
        ClassB.Do();
    }
}
Public class ClassB
{
    public string UsingType { get; set; }
    public void Do()
    {
        ClassC classC = new ClassC();
        Type type = Type.GetType(UsingType);
        Object obj = Activator.CreateInstance(type);
        classC.Do(obj); // Error : cannot convert from 'object' to 'ClassD'
    }
}
public class ClassC
{
    public void Do(ClassD classD) // If I change "ClassD" to "Object" It works!!
    {
        //Do something with classD
    }
}

我收到此错误：＆＃34;无法转换为＆＃39; object＆＃39;到＆＃39; ClassD＆＃39;。＆＃34;

如果我改变＆＃34;做＆＃34;方法参数＆＃34; ClassC＆＃34;来自＆＃34; ClassD＆＃34;到＆＃34;对象＆＃34;错误消失然后我可以把它投射到＆＃34; ClassD＆＃34;并使用该参数。但那不是我想要的。

有没有办法施展＆＃34; obj＆＃34; by＆＃34; UsingType＆＃34;字符串到＆＃34; ClassD＆＃34; （＆＃34;＆＃34;＆＃34; ClassB＆＃34的方法;）并消除编译时错误？

换句话说:(因为＆＃34; ClassA＆＃34;知道类型名称字符串并将其传递给＆＃34; ClassB＆＃34;）我怎样才能从＆＃34;对象＆＃34;到#C; ClassC＆＃34;的类型请问？

Answer 1

由于您确定ClassC的类型为ClassC obj = (ClassC)Activator.CreateInstance(type); classC.Do(obj);，因此只需将其转换为预期类型即可。

Object

进一步说明这一点：ToString()是一种泛型类型，并且只有全局可用的属性/方法（例如GetHashCode()或null。）

将其强制转换为类意味着编译器会尝试转换它，如果转换失败则返回public static String rfc5987_encode(final String s) throws UnsupportedEncodingException { final byte[] s_bytes = s.getBytes("UTF-8"); final int len = s_bytes.length; final StringBuilder sb = new StringBuilder(len << 1); final char[] digits = {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'}; final byte[] attr_char = {'!','#','$','&','+','-','.','0','1','2','3','4','5','6','7','8','9', 'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z','^','_','`', 'a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z','|', '~'}; for (int i = 0; i < len; ++i) { final byte b = s_bytes[i]; if (Arrays.binarySearch(attr_char, b) >= 0) sb.append((char) b); else { sb.append('%'); sb.append(digits[0x0f & (b >>> 4)]); sb.append(digits[b & 0x0f]); } } return sb.toString(); }。

如何通过类型名称转换Object并将其作为参数传递给另一个方法

1 个答案: