LINQ到實體無法識別方法「的Int32解析（System.String）」的方法，而這種方法不能被翻譯成店表達

Question

我來到這裏這個錯誤是我的代碼

var query1 = (from cust1 in context2.Clients 
       where cust1.ID == int.Parse(textBox1.Text) 
       select cust1).FirstOrDefault();` 

即使我的ID是一個i​​nt不是字符串

Answer 1

呼叫Parse方法查詢外：

var id=int.Parse(textBox1.Text); 
var result=context2.Clients.FirstOrDefault(cust=> cust.ID ==id); 

Answer 2

我想最簡單的解決辦法是將轉換爲int BEF礦石查詢：

var id = int.Parse(textBox1.Text); 
var query1 = (from cust1 in context2.Clients 
       where cust1.ID == id 
       select cust1).FirstOrDefault(); 

或者，對於錯誤處理的緣故：

var id = 0; 
if (!int.TryParse(textBox1.Text, out id)) { 
    // raise an error condition 
} 
var query1 = (from cust1 in context2.Clients 
       where cust1.ID == id 
       select cust1).FirstOrDefault(); 

Answer 3

你必須先設置int.Parse給一個變量，就像這樣：

var intValue = int.Parse(textBox1.Text); 
var query1 = (from cust1 in context2.Clients 
          where cust1.ID == intValue 
          select cust1).FirstOrDefault();