在LINQ查询中使用字符串

Question

I am currently developing a WPF project in c#. The project takes a string (newMemoryRFID) which is defined when the page is initialised and uses it in a query. Like so

var query = 
            from c in MemoryData.Memory
                    where c.RFID == newMemoryRFID
                    select c;
        this.DataContext = query;
        this.View = ((CollectionView)(CollectionViewSource.GetDefaultView(this.DataContext)));

This produces an empty DataContext

However when I use test data which is the same as what newMemoryRFID would be the query ie

var query = 
            from c in MemoryData.Memory
                    where c.RFID == "0F02D76B05"
                    select c;
        this.DataContext = query;
        this.View = ((CollectionView)(CollectionViewSource.GetDefaultView(this.DataContext)));

The query gets the correct record. As you may be able to tell I'm not the best programmer so the simpler your answer the better. And thanks very much in advance

Answer 1

This is the time to use your debugger. It sounds like newMemoryRFID isn't set to "0F02D76B05" at the time that query is created.

If you can't step into it, at least do

Debug.WriteLine(string.Format("newMemoryRFID = {0}", newMemoryRFID); 

before the line

var query = ...

Answer 2

尝试在开头和结尾处都修剪字符串，以获取可能导致空格匹配失败的空白。