c# 为什么这一行需要强制转换？

Question

// A single blog entry
public class BlogEntry
{
    public string ID;
    public string Title;
    public string Entry;
    public DateTime Date;
    public int UserID;

    // Load an entry based on ID
    public BlogEntry(int EntryID)
    {
        DataClassesDataContext db = new DataClassesDataContext();
        var q = (from Blog in db.tblBlogEntries where Blog.ID == EntryID select Blog).Single();

        // Fill data
        this.ID = EntryID;
        this.Title = q.title;
        this.Entry = q.entry;
        this.Date = (DateTime)q.date;
        this.UserID = (int)q.userID;
    }
}

this.ID = EntryID 抛出错误:

Cannot implicity turn type 'string' to 'int'

我很困惑，因为它们都被定义为整数，非常明确!

Answer 1

在您的类定义中，ID 被定义为字符串

 public string ID;

并且您正在尝试分配一个 int。这就是为什么。