将空值放入对象列表答案

【问题标题】：Putting null values in object list将空值放入对象列表
【发布时间】：2016-07-21 01:37:40
【问题描述】：

我有一个用于从数据库中获取数据的类和一个用于在网格视图中显示它们的网络表单。这是我的课：

public class Personel
{
    dincerelektrnik_AracTakipEntities entity = new dincerelektrnik_AracTakipEntities();

    public Personel(int DriverId, string DriverName, string DriverSurname, string DriverPosition, 
        bool DriverGender, string DriverImage, string DriverEmail,string Password, 
        DateTime? DriverBirthDate)
    {
        this.DriverId = driverId;
        this.DriverName = driverName;
        this.DriverSurname = driverSurname;
        this.DriverPosition = driverPosition;
        this.Gender = gender;
        this.DriverImage = driverImage;
        this.DriverEmail = driverEmail;
        this.Password = password;
        this.BirthDate = birthDate;
    }

    private int driverId;
    public int DriverId
    {
        get { return driverId; }
        set { driverId = value; }
    }

    private string driverName;
    public string DriverName
    {
        get { return driverName; }
        set { driverName = value; }
    }

    private string driverSurname;
    public string DriverSurname
    {
        get { return driverSurname; }
        set { driverSurname = value; }
    }

    private string password;
    public string Password
    {
        get { return password; }
        set { password = value; }
    }

    private DateTime? birthDate;
    public DateTime? BirthDate
    {
        get {
            if (birthDate.HasValue)
                return birthDate;
            else
                return DateTime.Now.Date;
        }
        set { birthDate = value; }
    }

    private string driverPosition;
    public string DriverPosition
    {
        get { return driverPosition; }
        set { driverPosition = value; }
    }

    private bool gender;
    public bool Gender
    {
        get { return gender; }
        set { gender = value; }
    }

    private string driverImage;
    public string DriverImage
    {
        get { return driverImage; }
        set { driverImage = value; }
    }

    private string driverEmail;
    public string DriverEmail
    {
        get { return driverEmail; }
        set { driverEmail = value; }
    }

    public List<Personel> GetAllDrivers() 
    {
        List<Personel> personeller = new List<Personel>();

        var drivers = entity.prGetDrivers();
        foreach (var driver in drivers) 
        {
            personeller.Add(new Personel(driver.DriverId, driver.DriverName, driver.DriverSurname,
                driver.DriverPosition, driver.DriverGender, driver.DriverImage, driver.DriverEmail,
                driver.Password, driver.DriverBirthDate));
        }
        return personeller;
    }
}

还有我的网格视图：

<asp:GridView ID="GridViewPersoneller" runat="server" AutoGenerateColumns="false">
            <Columns>
                <asp:TemplateField HeaderText="Ad/Soyad">
                    <ItemTemplate>
                        <%#Eval("DriverName") %>&nbsp;<%#Eval("DriverSurname") %>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField>
                    <ItemTemplate>
                        <%#Eval("DriverEmail") %>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField>
                    <ItemTemplate>
                        <%#Eval("DriverBirthDate") %>
                    </ItemTemplate>
                </asp:TemplateField>

            </Columns>
        </asp:GridView>

还有 webform 的代码隐藏：

Personel personel = new Personel(1, "deneme", "deneme", "deneme", true, "deneme", "deneme", "deneme", DateTime.Now.Date);

    protected void Page_Load(object sender, EventArgs e)
    {
        FillPeronselGridView();
    }

    protected void FillPeronselGridView() 
    {
        List<Personel> personelList = personel.GetAllDrivers();
        GridViewPersoneller.DataSource = personelList;
    }

当我运行代码时，我什么也看不到。不是错误或网格视图。当我调试时，我看到我使用存储过程获取所有数据并将它们存储在“驱动程序”变量中没有问题，但是当将它们添加到对象列表中时，它会添加空值。为什么会发生这种情况，我该如何解决。感谢您的时间和支持。

【问题讨论】：

personeller in return personeller 在返回时包含值？
它包含 2 行（与我的数据库表相同的行号），但两行都只包含空值。我的意思是所有属性都包含空值。 @GuruprasadRao

标签： c# asp.net entity-framework oop gridview

【解决方案1】：

问题是，在构造函数中，您使用Titlecase 定义了变量，但在初始化属性时，您使用了类字段。

修改您的代码以使用传递的参数而不是类变量。

你的构造函数应该是。

    public Personel(int DriverId, string DriverName, string DriverSurname, string DriverPosition,
        bool DriverGender, string DriverImage, string DriverEmail, string Password,
        DateTime? DriverBirthDate)
    {
        this.DriverId = DriverId;
        this.DriverName = DriverName;
        this.DriverSurname = DriverSurname;
        this.DriverPosition = DriverPosition;
        this.Gender = DriverGender;
        this.DriverImage = DriverImage;
        this.DriverEmail = DriverEmail;
        this.Password = Password;
        this.BirthDate = DriverBirthDate;
    }

【讨论】：