Lambda表达式C#无法转换为对象类型,并以ref引起失败 [英] Lambda expression C# failed to convert to the object type and fail with ref
本文介绍了Lambda表达式C#无法转换为对象类型,并以ref引起失败的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
有这样的功能:
private static void EncodeString(ref string str)
{
using (RLE inst_rle = new RLE())
{
string str_encoded = inst_rle.Encode(ref str);
Console.WriteLine(
"\r\nBase string ({0} chars): {1}\r\nAfter RLE-encoding ({2} chars): {3}\r\nCompression percentage: %{4}",
str.Length, str, str_encoded.Length, str_encoded,
() => { (100 * (str.Length - str.encoded.Length) / str.Length); }
);
}
}
我记得这是C#中的lambdas风格: ()=> {<动作>;
As I remember it's a style of lambdas in C#: () => { < action > ; }
但是得到这样的错误:
- 无法转换lambda表达式键入对象,因为
- 只有赋值,调用,增量,减量和新的对象表达式才能用作语句 li>
- 不能在匿名方法,lambda表达式或查询表达式中使用ref或out参数'str'
- 不能在匿名方法,lambda表达式或查询表达式中使用ref或out参数'str'
- Cannot convert lambda expression to type 'object' because it
- Only assignment, call, increment, decrement, and new object expressions can be used as a statement
- Cannot use ref or out parameter 'str' inside an anonymous method, lambda expression, or query expression
- Cannot use ref or out parameter 'str' inside an anonymous method, lambda expression, or query expression
代理服务器中的C#EXACLTY中的Lambda如何在我的应用程序(控制台应用程序)中使用Lambda / Func< T>,如()=> {} $>
推荐答案
我不太确定为什么你想在这里使用一个lambda,它看起来像你想要的:
I'm not really sure why you want to use a lambda here, it looks like you want:
Console.WriteLine(@"\r\nBase string ({0} chars): {1}\r\nAfter RLE-encoding
(
{2} chars): {3}\r\nCompression percentage: {4}",
str.Length, str, str_encoded.Length, str_encoded,
(100 / str.Length) * (str.Length / str_encoded.Length)
);
正如评论指出的那样,您需要在格式字符串前加一个 @
,因为它跨越多行。
As the comment points out, you need to prefix the format string with an @
since it spans multiple lines.
这篇关于Lambda表达式C#无法转换为对象类型,并以ref引起失败的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!
查看全文