“无过载方法'的ToString'采取'1'参数'错误发生在格式化日期时间字段为字符串ON＆QUOT; DD-MM-YYYY＆QUOT;格式 [英] 'No overload for method 'ToString' takes '1' arguments' error occur While Formating Datetime Field To String ON "dd-MM-yyyy" format

问题描述

我一直在asp.net 3.5.I想从SqlDataReader的转换datetime数据为String的DD-MM-YYYY格式。
但是当我使用DD-MM-YYYY格式化参数为rdMonthlyLeave [LEAVE_DATE]。的ToString（DD-MM-YYYY ）浏览器返回编译误差

I have been working on asp.net 3.5.I want to Convert a DateTime Data from sqldatareader to a String on "dd-MM-yyyy" Format. But when I use "dd-MM-yyyy" formatting parameter as "rdMonthlyLeave["LEAVE_DATE"].ToString("dd-MM-yyyy")" browser returns compile error as

编译器错误信息：CS1501：无过载方法'的ToString'采取'1'参数

Compiler Error Message: CS1501: No overload for method 'ToString' takes '1' arguments

你有一个解决方案？

推荐答案

您需要将其转换为的DateTime 第一：

You need to cast it to DateTime first:

DateTime leave = (DateTime) rdMonthlyLeave["LEAVE_DATE"];
DoSomethingWith(leave.ToString("dd-MM-yyyy"));

或只是

((DateTime)rdMonthlyLeave["LEAVE_DATE"]).ToString("dd-MM-yyyy")

DataReader的索引器的返回类型就是对象和对象没有过载的ToString 这需要一个字符串。不要忘记的重载的是一个编译时的决定 - 编译器选取具有兼容签名适当的方法，也是唯一的覆盖的发生根据执行时的类型。在这种情况下出现的是的任何的ToString超载与兼容的签名，所以你得到一个编译时错误。

The return type of the DataReader indexer is just object, and object doesn't have an overload of ToString which takes a string. Don't forget that overloading is a compile-time decision - the compiler picks the appropriate method with a compatible signature, and only overriding occurs based on the execution-time type. In this case there is no overload of ToString with a compatible signature, so you get a compile-time error.

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