英文:
Operator '!=' cannot be applied to operands of type 'Student' and 'int'
问题
我尝试将索引变量也更改为仍然给出相同的错误
public void UpdateStudent(int rollNo, Student updatedStudent)
{
var index = _list.FirstOrDefault(s => s.RollNo == rollNo);
if (index != null)
{
index.Name = updatedStudent.Name;
index.RollNo = updatedStudent.RollNo;
index.Marks = updatedStudent.Marks;
index.Branch = updatedStudent.Branch;
index.Location = updatedStudent.Location;
}
}
我已尝试更改其类型
英文:
I tried making index var also still it gives the same error
public void UpdateStudent(int rollNo, Student updatedStudent)
{
var index = _list.FirstOrDefault(s => s.RollNo == rollNo);
if (index != -1)
{
index.Name = updatedStudent.Name;
index.RollNo = updatedStudent.RollNo;
index.Marks = updatedStudent.Marks;
index.Branch = updatedStudent.Branch;
index.Location = updatedStudent.Location;
}
}
I have tried changing it type
答案1
得分: 3
FirstOrDefault返回列表中的项，而不是项的索引！
你应该使用item!=null进行检查，如下所示：
public void UpdateStudent(int rollNo, Student updatedStudent)
{
var item = _list.FirstOrDefault(s => s.RollNo == rollNo);
if (item != null)
{
item.Name = updatedStudent.Name;
item.RollNo = updatedStudent.RollNo;
item.Marks = updatedStudent.Marks;
item.Branch = updatedStudent.Branch;
item.Location = updatedStudent.Location;
}
}
英文:
FirstOrDefault returns the item from the list, not the index of the item!
you should check with item!=null like so :
public void UpdateStudent(int rollNo, Student updatedStudent)
{
var item = _list.FirstOrDefault(s => s.RollNo == rollNo);
if (item != null)
{
item.Name = updatedStudent.Name;
item.RollNo = updatedStudent.RollNo;
item.Marks = updatedStudent.Marks;
item.Branch = updatedStudent.Branch;
item.Location = updatedStudent.Location;
}
}
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