当我在下拉列表中选择月份时，如何显示文本框中的天数 [英] how to display the number of days in the textbox when i select the month in the dropdownlist

问题描述

任何人都可以帮助我，当我在下拉列表中选择月份时如何显示文本框中的天数

can anyone help me,how to display the number of days in the textbox when i select the month in the dropdownlist

推荐答案

你可以使用DateTime.DaysInMonth Method [ ^ ]获取一个月内的天数并将结果分配到文本框中下拉列表的SelectedIndexChanged事件。

You can use DateTime.DaysInMonth Method[^] to get the number of days in a month and assign the result to your textbox in the SelectedIndexChanged event of your dropdown.

具体如何执行此操作取决于您首先加载到DropDownList中的内容（字符串与数字不同，将与月份不同）课程） - 以及您尝试工作的环境。基于Web的项目的解决方案将与Windows应用程序的解决方案不同（因为它将涉及Javascript来保存回发）。



但基本结构是相同：处理下拉的Changed事件，获取当前值，然后在表中查找或使用它的参数来访问天数。然后看一年检查闰年/二月问题，并设定值。



但是我们不能更具体而不了解更多关于你的环境。

Exactly how you do this depends on what you load into your DropDownList in the first place (a string would be different from a number, would be different from a Month class) - and also on what environment you are trying to work. The solution for a web based project would be different from that for a windows application (in that it would involve Javascript to save a postback).

But the basic structure is the same: handle the Changed event fro the drop down, get teh current value, then either look it up in a table or use it''s parameters to access the number of days. Then look at the year to check for leap years / February problems, and set teh value.

But we can''t be more specific without knowing a lot more about your environment.

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