linqto - sql查看是否没有结果。

How come my code is showing a syntax error on this block of code

为什么我的代码在这个代码块上显示语法错误

public string getPassword()
{
   DataClasses1DataContext myDbContext = new DataClasses1DataContext(dbPath);

   var password = (from user in myDbContext.Accounts
                   where user.accnt_User == txtUser.Text
                   select user.accnt_Pass).First();

   if (password == 0) 
   { }

   return password;
}

I want to know if the result of query is 0, if it is 0 I will close the operation or something like that. but It keeps showing an error how would I know if the result is 0? also if you have suggestions regarding my approach feel free to put it in

我想知道查询的结果是否为0，如果是0，我将关闭操作或类似的操作。但它总是显示一个错误我怎么知道结果是否为0呢?如果你对我的方法有什么建议，请随意提出来

1 个解决方案

#1

Calling .First() will result in an exception if there is no data returned...

如果没有返回数据，则调用.First()将导致异常……

Calling .FirstOrDefault() will return null if there is no data

如果没有数据，调用.FirstOrDefault()将返回null

public string getPassword()
{
   DataClasses1DataContext myDbContext = new DataClasses1DataContext(dbPath);

   var password = (from user in myDbContext.Accounts
                   where user.accnt_User == txtUser.Text
                   select user.accnt_Pass).FirstOrDefault();

   if (password == null) 
   {
      // no data found - do whatever is needed in that case...
   }

   return password;
}

#1