null引用对象未设置为label.text属性上的对象引用

Question

我一直绞尽脑汁(不难做到)试图把这个异常搞清楚.我有一个显示用户信息的表单.当我设置断点并逐步执行代码时.方法调用返回对象(在即时窗口中检查),但是当我将标识的用户属性分配给它时.

这是我的代码:

public Form2()
        {
            UserInfo user = FileAccess.UserInfoFromXML();
            // All the members of user exist.
            label1.Text = "Screen Name: " + user.ScreenName; //This is throwing an Null Reference exception the UserInfo is not null
            label2.Text = "Full Name: "+ user.FirstName + " " + user.LastName;
            label3.Text = "Address: " + user.StreetAddress + " " + user.City + " " + user.State + " " + user.Zip;
            label4.Text = "Email Address: " + user.email;
            label5.Text = "Date Of Birth: " + user.DateOfBirth;
            label6.Text = "Start Date: " + user.StartDate;
            DateTime dt = DateTime.Parse( user.StartDate );
            dt.AddDays( 30 );
            label7.Text = "End Date: " + dt.ToShortDateString();

        }

有任何想法吗？谢谢

Answer 1

你必须让InitializeComponent()调用保持在构造函数之上.

此设计器生成的方法初始化您的组件,以便null在您访问它们时不再使用标签.