我对C＃和实体框架还很陌生。
代码到达db.SaveChanges（）行时出现异常。
我试图用谷歌搜索，但没有帮助。
我提供了下面的代码。
任何帮助将不胜感激。
C＃代码：
这种方法是将数据插入数据库。
protected void scheduleAppointment(object sender, EventArgs e)
{
DentalClinicEntities1 db = new DentalClinicEntities1();
Appointment appointment = new Appointment();
Invoice invoice = new Invoice();
Patient patient = new Patient();
try
{
appointment.Patient_ID = Int32.Parse(txtPatientID.Text);
appointment.Appointment_Details = txtDetails.Text;
appointment.Appointment_Start_Date = DateTime.Parse(txtStartDate.Text);
appointment.Appointment_End_Date = DateTime.Parse(txtEndDate.Text);
appointment.First_Name = ddlDentist.Text;
appointment.Created_Date = DateTime.Now;
appointment.Created_By = Constants.Designation.Assistant_Admin.ToString();
appointment.Modified_Date = DateTime.Now;
appointment.Modified_By = Constants.Designation.Assistant_Admin.ToString();
db.Appointments.Add(appointment);
int result = db.SaveChanges();
if (result > 0)
{
MessageBox.Show("Appointment scheduled successfully !!");
txtPatientID.Text = string.Empty;
txtDetails.Text = string.Empty;
txtStartDate.Text = string.Empty;
txtEndDate.Text = string.Empty;
ddlDentist.SelectedIndex = 0;
}
}
catch (NullReferenceException ex)
{
Debug.WriteLine(ex.Message);
}
catch (DbEntityValidationException ex)
{
foreach (var eve in ex.EntityValidationErrors)
{
Console.WriteLine(eve.Entry.Entity.GetType().Name, eve.Entry.State);
foreach (var ve in eve.ValidationErrors)
{
Console.WriteLine(ve.PropertyName, ve.ErrorMessage);
}
}
}
}
Model Code:
public partial class Appointment
{
public Appointment()
{
this.Invoices = new HashSet<Invoice>();
}
public int Appointment_ID { get; set; }
public int Patient_ID { get; set; }
public string Appointment_Details { get; set; }
public System.DateTime Appointment_Start_Date { get; set; }
public System.DateTime Appointment_End_Date { get; set; }
public string First_Name { get; set; }
public System.DateTime Created_Date { get; set; }
public string Created_By { get; set; }
public System.DateTime Modified_Date { get; set; }
public string Modified_By { get; set; }
public virtual Patient Patient { get; set; }
public virtual ICollection<Invoice> Invoices { get; set; }
}
Stack Trace:
[NullReferenceException: Object reference not set to an instance of an object.]
System.Web.UI.ParseChildrenAttribute.GetHashCode() +26
System.Collections.Generic.ObjectEqualityComparer`1.GetHashCode(T obj) +23
System.Collections.Generic.HashSet`1.InternalGetHashCode(T item) +49
System.Collections.Generic.HashSet`1.AddIfNotPresent(T value) +34
System.Collections.Generic.HashSet`1.UnionWith(IEnumerable`1 other) +131
System.Collections.Generic.HashSet`1..ctor(IEnumerable`1 collection, IEqualityComparer`1 comparer) +125
System.Collections.Generic.HashSet`1..ctor(IEnumerable`1 collection) +49
System.Data.Entity.ModelConfiguration.Utilities.AttributeProvider.GetAttributes(Type type) +155
System.Data.Entity.ModelConfiguration.Utilities.AttributeProvider.GetAttributes(PropertyInfo propertyInfo) +236
System.Data.Entity.Internal.Validation.EntityValidatorBuilder.BuildPropertyValidator(PropertyInfo clrProperty) +71
System.Data.Entity.Internal.Validation.EntityValidatorBuilder.BuildValidatorsForProperties(IEnumerable`1 clrProperties, IEnumerable`1 edmProperties, IEnumerable`1 navigationProperties) +1235
System.Data.Entity.Internal.Validation.EntityValidatorBuilder.BuildTypeValidator(Type clrType, IEnumerable`1 edmProperties, IEnumerable`1 navigationProperties, Func`3 validatorFactoryFunc) +101
System.Data.Entity.Internal.Validation.EntityValidatorBuilder.BuildEntityValidator(InternalEntityEntry entityEntry) +249
System.Data.Entity.Internal.Validation.ValidationProvider.GetEntityValidator(InternalEntityEntry entityEntry) +135
System.Data.Entity.Internal.InternalEntityEntry.GetValidationResult(IDictionary`2 items) +100
System.Data.Entity.DbContext.ValidateEntity(DbEntityEntry entityEntry, IDictionary`2 items) +250
System.Data.Entity.DbContext.GetValidationErrors() +267
System.Data.Entity.Internal.InternalContext.SaveChanges() +107
System.Data.Entity.Internal.LazyInternalContext.SaveChanges() +53
System.Data.Entity.DbContext.SaveChanges() +52
Dental_Clinic.ScheduleAppointment.scheduleAppointment(Object sender, EventArgs e) in c:\Users\Karan\Documents\Visual Studio 2012\Projects\Dental Clinic\Dental Clinic\ScheduleAppointment.aspx.cs:40
System.Web.UI.WebControls.Button.OnClick(EventArgs e) +9628114
System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +103
System.Web.UI.WebControls.Button.System.Web.UI.IPostBackEventHandler.RaisePostBackEvent(String eventArgument) +10
System.Web.UI.Page.RaisePostBackEvent(IPostBackEventHandler sourceControl, String eventArgument) +13
System.Web.UI.Page.RaisePostBackEvent(NameValueCollection postData) +35
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1724
注册患者
我也使用相同的方法在注册病人的同时将数据插入表格。
protected void registerPatient(object sender, EventArgs e)
{
DentalClinicEntities1 db = new DentalClinicEntities1();
Patient patient = new Patient();
try
{
patient.First_Name = txtFirstName.Text;
patient.Last_Name = txtLastName.Text;
patient.Birth_Date = Convert.ToDateTime(txtBirthDate.Text);
patient.State = listState.Text;
patient.City = listCity.Text;
patient.Address = txtAddress.Text;
patient.Contact_Number = long.Parse(txtContact.Text);
patient.Pincode = Int32.Parse(txtPincode.Text);
patient.EmailID = txtEmail.Text;
patient.Gender = listGender.Text;
string issue = string.Empty;
for (int i = 0; i < lstBoxTest.Items.Count; i++)
{
if (lstBoxTest.Items[i].Selected)
issue += lstBoxTest.Items[i].Value + ",";
}
patient.Medical_Issue = issue;
patient.Type = listType.Text;
patient.Allergies = txtAllergies.Text;
patient.Is_Active = true;
patient.Created_Date = DateTime.Now;
patient.Created_By = Constants.Designation.Receptionist.ToString();
patient.Modified_Date = DateTime.Now;
patient.Modified_By = Constants.Designation.Receptionist.ToString();
db.Patients.Add(patient);
int result = db.SaveChanges();
if (result > 0)
{
MessageBox.Show("Record inserted successfully!!");
txtFirstName.Text = String.Empty;
txtLastName.Text = String.Empty;
txtBirthDate.Text = String.Empty;
listState.SelectedIndex = 0;
listCity.SelectedIndex = 0;
txtAddress.Text = String.Empty;
txtContact.Text = String.Empty;
txtPincode.Text = String.Empty;
txtEmail.Text = String.Empty;
listGender.SelectedIndex = 0;
lstBoxTest.ClearSelection();
listType.SelectedIndex = 0;
txtAllergies.Text = String.Empty;
}
else
{
MessageBox.Show("Record not inserted.");
}
}
catch (Exception exception)
{
Console.WriteLine(exception);
}
}