在将日期时间字段格式化为字符串ON时，发生“方法'ToString'不重载为'1'参数"错误.格式 [英] 'No overload for method 'ToString' takes '1' arguments' error occur While Formatting Datetime Field To String ON "dd-MM-yyyy" format

问题描述

我一直在asp.net 3.5上工作.我想将DateTime数据从sqldatareader转换为"dd-MM-yyyy"格式的字符串. 但是，当我使用"dd-MM-yyyy"格式参数作为"rdMonthlyLeave["LEAVE_DATE"].ToString("dd-MM-yyyy")"时，浏览器将返回编译错误为

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

编译器错误消息:CS1501:方法'ToString'的重载没有接受'1'参数

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

您有解决方案吗?

推荐答案

您需要先将其转换为DateTime:

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

或者只是

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

DataReader索引器的返回类型仅为object，而object没有具有字符串的ToString重载.不要忘记 overloading 是编译时的决定-编译器选择具有兼容签名的适当方法，并且只有 overrideing 会根据执行时类型发生.在这种情况下， 不会包含具有兼容签名的ToString重载，因此会出现编译时错误.

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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