C# 非静态方法需要一个目标
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Non static method requires a target
提问by Khnemu
private PMS_USERS currUser;
private bool validateUserName()
{
dbContext = new PmsEntities();
var validateUser = dbContext.PMS_USERS.Where(p=> p.LOGICALREF != currUser.LOGICALREF).Where(p=> p.USERNAME == currUser.USERNAME);
return !validateUser.Any();
}
Hello, I got an error while validating on my new user register form.
您好，我在验证我的新用户注册表时遇到错误。
My PMS_USERStable has no record(null). I also tried checking for nullcontrol(s) for currUser.
我的PMS_USERS表没有记录（null）。我也试过检查null控制（多个）currUser。
What am I missing?
我错过了什么？
Error is :
错误是：
Non static method requires a target
非静态方法需要一个目标
采纳答案by Rom Eh
You should first test if currUser is null or not and your dbContext too.
您应该首先测试 currUser 是否为 null 以及您的 dbContext 。
if (currUser == null) return false;
if (dbContext == null) throw new Exception ("The dbContext has not been set");
Secondly, you can simplify your query like yhat :
其次，您可以像 yhat 一样简化您的查询：
var validateUser = dbContext.PMS_USERS.Where(p=> p.LOGICALREF != currUser.LOGICALREF && p.USERNAME == currUser.USERNAME);
And then change the return statement to :
然后将返回语句更改为：
return (validateUser.FirstOrDefault() != null);
You can alternativelly use SingleOrDefault statement insead of FirstOrDefault, if you want to be sure there is only one user corresponding to your criteria.
如果您想确保只有一个用户符合您的条件，您也可以使用 SingleOrDefault 语句代替 FirstOrDefault。
回答by Carlos Landeras
"Non static method requires a target" means that some object inside the scope is null.
“非静态方法需要目标”意味着范围内的某个对象是null.
Try checking the context and the var result values:
尝试检查上下文和 var 结果值：
dbContext = new PmsEntities();
if (dbContext != null && currUser != null)
{
var validateUser = dbContext.PMS_USERS.Where(p=> p.LOGICALREF != currUser.LOGICALREF && p.USERNAME == currUser.USERNAME);
if (validateUser !=null)
{
return !validateUser.Any();
}
else
return null;
}
Check it and tell us if you have the same exception.
检查它并告诉我们您是否有相同的异常。
回答by Sysketov Alexey
Use
用
private PMS_USERS currUser;
private bool validateUserName()
{
dbContext = new PmsEntities();
return PMS_USERS != null
? var validateUser = dbContext.PMS_USERS.Where(p=> p.LOGICALREF != currUser.LOGICALREF).Where(p=> p.USERNAME == currUser.USERNAME).Any()
: false;
}
