thanks Xudong it works. I only needed to restart visual studio
Linq to sql class error: must add reference to assembly Syste.data.linq
I created .Net Framework web form app in VS 2019 community. I added linq tosql class (dmbl) using table from AdventureWorks CountryRegions table. The class was created successfully . However I get error in my Business class (Bal): Error says:
CS0012 The type 'Table<>' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.Data.Linq, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089'.
I can see System.Data.Linq added to the references.
And System.Linq in Nuget packages.
using Microsoft.Owin;
using Owin;
using System;
using System.Threading.Tasks;
//using System.Data.Common
using System.Linq;
using System.Collections.Generic;
//[assembly: OwinStartup(typeof(OBjectDSDemo.App_Code.Biz.Bal))]
namespace OBjectDSDemo.App_Code.Biz
{
public class Bal
{
public List<CountryRegion> GetCustomers()
{
var contxt = new DataClasses1DataContext();
//customers=from c in
return (from c in contxt.CountryRegions select c.Country).toList();
}
}
}
#pragma warning disable 1591
//------------------------------------------------------------------------------
// <auto-generated>
// This code was generated by a tool.
// Runtime Version:4.0.30319.42000
//
// Changes to this file may cause incorrect behavior and will be lost if
// the code is regenerated.
// </auto-generated>
//------------------------------------------------------------------------------
namespace OBjectDSDemo
{
using System.Data.Linq;
using System.Data.Linq.Mapping;
using System.Data;
using System.Collections.Generic;
using System.Reflection;
using System.Linq;
using System.Linq.Expressions;
using System.ComponentModel;
using System;
[global::System.Data.Linq.Mapping.DatabaseAttribute(Name="AdventureWorks")]
public partial class DataClasses1DataContext : System.Data.Linq.DataContext
{
private static System.Data.Linq.Mapping.MappingSource mappingSource = new AttributeMappingSource();
#region Extensibility Method Definitions
partial void OnCreated();
partial void InsertCountryRegion(CountryRegion instance);
partial void UpdateCountryRegion(CountryRegion instance);
partial void DeleteCountryRegion(CountryRegion instance);
#endregion
public DataClasses1DataContext() :
base(global::System.Configuration.ConfigurationManager.ConnectionStrings["AdventureWorksConnectionString"].ConnectionString, mappingSource)
{
OnCreated();
}
public DataClasses1DataContext(string connection) :
base(connection, mappingSource)
{
OnCreated();
}
public DataClasses1DataContext(System.Data.IDbConnection connection) :
base(connection, mappingSource)
{
OnCreated();
}
public DataClasses1DataContext(string connection, System.Data.Linq.Mapping.MappingSource mappingSource) :
base(connection, mappingSource)
{
OnCreated();
}
public DataClasses1DataContext(System.Data.IDbConnection connection, System.Data.Linq.Mapping.MappingSource mappingSource) :
base(connection, mappingSource)
{
OnCreated();
}
public System.Data.Linq.Table<CountryRegion> CountryRegions
{
get
{
return this.GetTable<CountryRegion>();
}
}
}
[global::System.Data.Linq.Mapping.TableAttribute(Name="Person.CountryRegion")]
public partial class CountryRegion : INotifyPropertyChanging, INotifyPropertyChanged
{
private static PropertyChangingEventArgs emptyChangingEventArgs = new PropertyChangingEventArgs(String.Empty);
private string _CountryRegionCode;
private string _Name;
private System.DateTime _ModifiedDate;
#region Extensibility Method Definitions
partial void OnLoaded();
partial void OnValidate(System.Data.Linq.ChangeAction action);
partial void OnCreated();
partial void OnCountryRegionCodeChanging(string value);
partial void OnCountryRegionCodeChanged();
partial void OnNameChanging(string value);
partial void OnNameChanged();
partial void OnModifiedDateChanging(System.DateTime value);
partial void OnModifiedDateChanged();
#endregion
public CountryRegion()
{
OnCreated();
}
[global::System.Data.Linq.Mapping.ColumnAttribute(Storage="_CountryRegionCode", DbType="NVarChar(3) NOT NULL", CanBeNull=false, IsPrimaryKey=true)]
public string CountryRegionCode
{
get
{
return this._CountryRegionCode;
}
set
{
if ((this._CountryRegionCode != value))
{
this.OnCountryRegionCodeChanging(value);
this.SendPropertyChanging();
this._CountryRegionCode = value;
this.SendPropertyChanged("CountryRegionCode");
this.OnCountryRegionCodeChanged();
}
}
}
[global::System.Data.Linq.Mapping.ColumnAttribute(Storage="_Name", DbType="NVarChar(50) NOT NULL", CanBeNull=false)]
public string Name
{
get
{
return this._Name;
}
set
{
if ((this._Name != value))
{
this.OnNameChanging(value);
this.SendPropertyChanging();
this._Name = value;
this.SendPropertyChanged("Name");
this.OnNameChanged();
}
}
}
[global::System.Data.Linq.Mapping.ColumnAttribute(Storage="_ModifiedDate", DbType="DateTime NOT NULL")]
public System.DateTime ModifiedDate
{
get
{
return this._ModifiedDate;
}
set
{
if ((this._ModifiedDate != value))
{
this.OnModifiedDateChanging(value);
this.SendPropertyChanging();
this._ModifiedDate = value;
this.SendPropertyChanged("ModifiedDate");
this.OnModifiedDateChanged();
}
}
}
public event PropertyChangingEventHandler PropertyChanging;
public event PropertyChangedEventHandler PropertyChanged;
protected virtual void SendPropertyChanging()
{
if ((this.PropertyChanging != null))
{
this.PropertyChanging(this, emptyChangingEventArgs);
}
}
protected virtual void SendPropertyChanged(String propertyName)
{
if ((this.PropertyChanged != null))
{
this.PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
}
}
}
#pragma warning restore 1591
2 additional answers
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-
XuDong Peng-MSFT 10,511 Reputation points Microsoft Vendor
2020-12-04T09:28:37.573+00:00 Hi @kobosh ,
According to your description, I did some related searches on this issue.
And here is a similar case, you could try:
- Navigate to the web project's References node
- Find the reference to System.Data.Linq
- Open the VS Properties Window
- In the properties window, change Copy Local: False to
True
Or you could try copy the System.Data.Linq dll reference to bin directory.
Best regards,
Xudong Peng
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kobosh 176 Reputation points
2020-12-04T16:36:57.323+00:00 thanks Xudong it works. I only needed to restart visual studio