Asp.net 方法问题
我还有一个问题。我的方法:Asp.net 方法问题,asp.net,c#-4.0,Asp.net,C# 4.0,我还有一个问题。我的方法: public StudentProfile GetFullStudentProfile(int userID) { SqlConnection conn = new SqlConnection(Config.DbConnectionString); SqlCommand cmd = new SqlCommand("GetFullUserProfile", conn); cmd.CommandType = CommandType.StoredPr
public StudentProfile GetFullStudentProfile(int userID)
{
SqlConnection conn = new SqlConnection(Config.DbConnectionString);
SqlCommand cmd = new SqlCommand("GetFullUserProfile", conn);
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.Add(new SqlParameter("@UserID", SqlDbType.Int));
cmd.Parameters["@UserID"].Value = userID;
StudentProfile sp = null;
try
{
conn.Open();
SqlDataReader reader = cmd.ExecuteReader(CommandBehavior.SingleRow);
if (reader.Read())
{
sp = new StudentProfile((int)reader["UserID"], (string)reader["UserName"], (string)reader["UserFamilyName"], (DateTime)reader["UserBirthDay"], (string)reader["UserTelephone"], (string)reader["UserEmail"], (DateTime)reader["UserRegDate"], (string)reader["UserComment"], (bool)reader["UserActive"]);
}
reader.Close();
}
catch (Exception ex)
{
//lbl.Text = ex.Message;
}
finally
{
conn.Close();
}
return sp;
}
WebUserControl中的代码:
protected void ddlStudents_SelectedIndexChanged(object sender, EventArgs e)
{
CatalogAccess ca=new CatalogAccess();
lblEmail.Visible = true;
lblName.Visible = true;
lblTelephone.Visible = true;
HiddenID.Value = ddlStudents.SelectedValue;
lblName.Text = HiddenID.Value;
lblEmail.Text = ca.GetFullStudentProfile(ddlStudents.SelectedIndex).UserEmail;
lblFamilyName.Visible = true;
lblBirth.Visible = true;
ddlStudents.Items.Clear();
PopulateStudentsDDL();
}
UserDetails ud = ca.GetUser(24);
//HiddenID.Value = String.Format(ud.UserID);
lblName.Text = ud.UserName;
lblEmail.Text = ud.UserEmail;
lblFamilyName.Text = ud.UserFamilyName;
lblBirth.Text=String.Format("{0:dd/MM/yyy}",ud.UserBirthDay);
lblTelephone.Text = ud.UserTelephone;
当我运行代码时,我遇到异常
我是否正确理解问题出在方法GetFullStudentProfile()中?如果是这样的话,怎么能修复呢
我认为问题在于:
StudentProfile sp = null;
所以它说变量sp在try块中没有填充数据。是吗
现在添加StudentProfile.cs类列表:
public class StudentProfile
{
公共学生档案(int userID、string userName、string userFamilyName、DateTime userbirth、string userphone、string userEmail、DateTime userRegDate、string userComment、bool userActive)
{
UserID=UserID;
用户名=用户名;
UserFamilyName=UserFamilyName;
用户生日=用户生日;
用户电话=用户电话;
UserEmail=UserEmail;
UserRegdate=UserRegdate;
UserComment=UserComment;
UserActive=UserActive;
}
}什么是空值?我打赌
GetFullStudentProfile
方法返回null。是的,事情就是这样。找不到与通过的ID匹配的学生。我将在您的客户端代码中执行以下操作:
StudentProfile sp=ca.GetFullStudentProfile(ddlStudents.SelectedIndex);
lblEmail.Text = sp != null ? sp.UserEmail : string.Empty;
此外,我还将GetFullStudentProfile
方法的读取器操作重写为如下内容:
conn.Open();
SqlDataReader reader = cmd.ExecuteReader(CommandBehavior.SingleRow);
if (reader.Read())
{
sp = new StudentProfile((int)reader["UserID"], (string)reader["UserName"], (string)reader["UserFamilyName"], (DateTime)reader["UserBirthDay"], (string)reader["UserTelephone"], (string)reader["UserEmail"], (DateTime)reader["UserRegDate"], (string)reader["UserComment"], (bool)reader["UserActive"]);
}
reader.Close();
这只是例行的整容手术,看起来更漂亮,而且:
HiddenID.Value = ddlStudents.SelectedValue;
lblName.Text = HiddenID.Value;
我注意到在你的汽车中,名称被设置为1。因此,我认为您实际上是想将其设置为:
lblName.Text = ddlStudents.SelectedValue;
我不相信将该值设置为等于它本身会对您有任何好处。检查数据库,UserEmail列是否允许空值
另外,在您的数据库中,我相信UserID从1开始递增,对吗?我相信SelectedIndex从0开始。您可能需要将selectedvalue项增加1
我刚才看了你的另一个问题(http://stackoverflow.com/questions/5745820/assign-list-member-to-label)我觉得这里有更多的信息
如果您的数据库不允许可空类型,我将更改:
CatalogAccess ca=new CatalogAccess();
lblEmail.Visible = true;
lblName.Visible = true;
lblTelephone.Visible = true;
HiddenID.Value = ddlStudents.SelectedValue;
lblName.Text = HiddenID.Value;
lblEmail.Text = ca.GetFullStudentProfile(ddlStudents.SelectedIndex).UserEmail;
lblFamilyName.Visible = true;
lblBirth.Visible = true;
ddlStudents.Items.Clear();
PopulateStudentsDDL();
致:
你也可以考虑把你的呼叫标签放在SP中!空条件,因此只有在显示有效人员时,才会实际显示这些标签。否则就把它们放在前面
否则我会像迪米特里那样说lblName.Text = student.UserName != null ? student.UserName : String.Empty;
lblEmail.Text = student.UserEmail != null ? student.UserEmail : String.Empty;
// etc.
如果可以为空,则实际上可以将student对象指定给,但属性可能不指定,这可能会在运行时导致应用程序出现问题。确定。我提出了一个新方法:
public UserDetails GetUser(int userID)
{
SqlConnection conn = new SqlConnection(Config.DbConnectionString);
SqlCommand cmd = new SqlCommand("GetFullUserProfile", conn);
cmd.CommandType = CommandType.StoredProcedure;
cmd.Parameters.Add(new SqlParameter("@UserID", SqlDbType.Int, 4));
cmd.Parameters["@UserID"].Value = userID;
try
{
conn.Open();
SqlDataReader reader = cmd.ExecuteReader(CommandBehavior.SingleRow);
// Check if the query returned a record.
if (!reader.HasRows) return null;
// Get the first row.
reader.Read();
UserDetails emp = new UserDetails((int)reader["UserID"], (string)reader["UserName"], (string)reader["UserFamilyName"], (DateTime)reader["UserBirthDate"], (string)reader["UserTelephone"], (string)reader["UserEmail"], (DateTime)reader["RegDate"], (string)reader["UserComment"], (int)reader["UserActive"]);
reader.Close();
return emp;
}
catch (SqlException err)
{
throw new ApplicationException("Data error.");
}
finally
{
conn.Close();
}
}
新类别:
using System;
public class UserDetails
{
public UserDetails(int userID, string userName, string userFamilyName, DateTime userBirthDate, string userTelephone, string userEmail, DateTime regDate, string userComment, int userActive)
{
UserID = userID;
UserName = userName;
UserFamilyName = userFamilyName;
UserBirthDay = userBirthDate;
UserTelephone = userTelephone;
UserEmail = userEmail;
RegDate = regDate;
UserComment = userComment;
userActive = UserActive;
}
public int UserID
{ get; set; }
public string UserName
{ get; set; }
public string UserFamilyName
{ get; set; }
public DateTime UserBirthDay
{ get; set; }
public string UserTelephone
{ get; set; }
public string UserEmail
{ get; set; }
public DateTime RegDate
{ get; set; }
public string UserComment
{ get; set; }
public int UserActive
{ get; set; }
}
之后,在我的WebUserControl后台代码中:
protected void ddlStudents_SelectedIndexChanged(object sender, EventArgs e)
{
CatalogAccess ca=new CatalogAccess();
lblEmail.Visible = true;
lblName.Visible = true;
lblTelephone.Visible = true;
HiddenID.Value = ddlStudents.SelectedValue;
lblName.Text = HiddenID.Value;
lblEmail.Text = ca.GetFullStudentProfile(ddlStudents.SelectedIndex).UserEmail;
lblFamilyName.Visible = true;
lblBirth.Visible = true;
ddlStudents.Items.Clear();
PopulateStudentsDDL();
}
UserDetails ud = ca.GetUser(24);
//HiddenID.Value = String.Format(ud.UserID);
lblName.Text = ud.UserName;
lblEmail.Text = ud.UserEmail;
lblFamilyName.Text = ud.UserFamilyName;
lblBirth.Text=String.Format("{0:dd/MM/yyy}",ud.UserBirthDay);
lblTelephone.Text = ud.UserTelephone;
并使该方法起作用。所以,这个阶段已经准备好了。谢谢所有帮助我的人。线程已关闭。在该行上设置断点,然后进入getfullstudentprofile方法。这会让你更好地了解失败的地方我做到了。如何进入getfullstudentprofile?我拍了一张IDE的截图,但忘了你不能在评论中放截图。如果你没有修改你的快捷方式,它将是F11。如果有,请单击调试->单步执行是否确实需要将所选索引指定为GetFullStudentProfile方法的参数?可能应该是某个学生id。无论如何,在使用UserEmail属性之前,您需要检查调用结果是否为null。HiddenID.Value=ddlstustudents.SelectedValue;lblName.Text=HiddenID.Value//我刚刚检查了dropdownlist是否有效。早上好!我做了个测试。显式放置userID:StudentProfile student=ca.GetFullStudentProfile(2);如果(student!=null){lblName.Text=student.UserName;lblEmail.Text=student.UserEmail;//其他标签在这里(我只看到名称和电子邮件)}或者{lblName.Text=“它是null”;}并且得到的名称标签上写着“它是null”。所以问题是该方法没有获取UserIDI,我认为问题出在GetFullStudentProfile()方法中。唉,我看不见了。在这一行,lblEmail.Text=ca.GetFullStudentProfile(ddlstusts.SelectedIndex);右键单击GetFullStudentProfile并转到定义。在返回sp行上设置断点。在调试中运行它。当它到达返回sp行时,将鼠标悬停在sp上。如果它为null,则在获取student profile对象时会出现问题。在这种情况下,我会在GetFullStudentProfile对象的前面设置一个断点,只需单步执行它,直到它进入catch(Exception ex)块。如果不为null并将自身列为学生档案对象,请单击弹出的工具提示中的+符号,查看要检索的所有属性(电子邮件、姓名等)的显示。从那里你会知道你的采集功能是如何为你工作的。另外,我相信我在另一篇文章中读到了您正在使用SQLServer2005或2008。ADO是要求还是偏好?因为如果不是的话,你可能会对LINQ感兴趣。在设置dbml之后,获取函数基本上就是创建一个db对象,创建一个sp对象设置为=(从db_object.GetFullStudentProfiles中的c开始,其中c.UserId==UserId选择c)@找到了Dimitri Id。问题是sp未被填充,结果返回null。@Nathan调试器显示用户ID值并不意味着数据库中有与该ID匹配的记录。请尝试以下操作:从UserStable中选择*,其中ID=2。如果有记录,那么您在StudentProfile类的构造函数中做了一些错误的事情。select*from dbo.Users,其中UserID=3返回了我的记录。此语句有效。您是否尝试将userID=3传递给上述方法?如果是这样,它会返回什么吗?如果没有,请向我们展示StudentProfile类及其构造函数和字段的定义/properties@Dimitri你好,我试过了:StudentProfile student=ca.GetFullStudentProfile(3);如果(student!=null){lblName.Text=student.UserName;lblEmail.Text=student.UserEmail;