如果database列为null，则用string替换

本文介绍了如果database列为null，则用string替换的处理方法，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

i只想问一下如何使用sql server在C＃中编写以下场景： 1.我正在编写一个页面，反映表单是否已经提交。我有[name]列和[date submitted]列。 2.我想替换[date submitted]列中的数据。如果[提交日期]有条目，我希望将其反映为已提交，如果[提交日期]为空，则无法提交。 3. [名称]和[提交日期]来自不同的数据库：mydb.name和project.dateSubmitted 4.它将反映到一个gridview 5.在gridview内部，会有一列按钮。如果[提交日期]为空，则该按钮将被禁用。如果[提交日期]有条目，则启用。 感谢

i just want to ask how to code in C# using sql server the following scenario: 1. I am coding a page that reflects if a form is already submitted or not. i have [name] column and [date submitted] column. 2. I want to replace the data inside the [date submitted] column. I want to reflect it as ALREADY SUBMITTED if [date submitted] has entry and NOT YET SUBMITTED if [date submitted] is null. 3. [name] and [date submitted] comes from different databases: mydb.name and project.dateSubmitted 4. it will reflect into just one gridview 5. inside gridview, there will be a column for buttons. if [date submitted] is null, the button will be disabled. enabled if [date submitted] has entry. thanks

推荐答案

尝试 Try //dr is datareader if ( dr[0][0] is DBNull ) { //Handle null here }

处理此问题的最佳方法是从数据库中获取所需的结果。查询将如下所示： The best way to handle this is get the required result from the database. The query would be like the one below: SELECT NAME, CASE WHEN dateSubmitted IS NULL THEN 'NOT YET SUBMITTED' ELSE 'ALREADY SUBMITTED' END 'STATUS' FROM MYTABLE